PSY280 Final Exam
M ganglion cells
"Large cells." Connect to the magnocellular pathway: involved in motion processing. Excellent temporal resolution, but poor spatial resolution
Oliver Selfridge's computational model of letter recognition
"Perception by committee" "Demons" loosely represent neurons; each level represents a different brain area
P ganglion cells
"Small cells." Connect to the parvocellular pathway; involved in fine visual acuity, color, and shape processing. They have poor temporal resolution but good spatial resolution
Presbyopia
"old sight" inability to accomodate nearby objects
Vagus nerve
(Cranial nerve X) - for the fixed part of the tongue furthest in the back of the mouth cavity
Fundamental frequency
(first harmonic): lowest frequency component of the sound Perception of timbre depends on context in which sound is heard
Anatomy of a neuron
- Dendrites : fibers that receive messages from other neurons - Cell body (with nucleus) integrates incoming signals from dendrites - Axons : fibers that carry outgoing signals to other neurons or organs. There are gaps between - Synapse: region where the neuron meets other neuron or target cell - Signals are sent via Neurotransmitters
Receptive field properties of IT neurons
- Very large—some cover half the visual field - Don't respond well to spots or lines - Do respond well to stimuli such as hands, faces, or objects, animals, and vehicles
OFF-center ganglion cell responds when
-offset of small bright light in center of receptive field -onset of annulus of light in surround of receptive field
ON-center ganglion cell responds when
-onset of small bright light in center of receptive field -offset of annulus of light in surround of receptive field
Where is the ILD nonexistent
0 degrees and 180 degrees
Cortical magnification
1 degree of visual angle at fovea is processed by at 15 times more neurons than 1 degree of visual angle just 10 degrees away from fovea
Absolute threshold for taste
1 teaspoon of sugar in 2 gallons of water
Viewpoint Invariance
1. A property of an object that does not change when observer viewpoint changes. 2. A class of theories of object recognition that proposes representations of objects that do not change when viewpoint changes.
summary of midlevel vision
1. Bring together what should be brought together. - GROUPING MECHANISMS 2. Split asunder what should be split asunder. - FIGURE GROUND SEGMENTATION 3. Use what you know. - Use heuristics for findings corners, etc... and divide objects into parts. 4. Avoid accidents. - Do not consider as likely accidental view point representations 5. Seek consensus and avoid ambiguity.
Three steps to color perception
1. Detection 2. Discrimination 3. Appearance
Four tactile receptors
1. Meissner corpuscles 2. Merkel cell neutrite complexes 3. Pacinian corpuscles 4. Ruffini endings
Vertical Pathway
1. Photoreceptor 2. Bipolar Cell 3. Ganglion
What are the steps to face perception
1. Recognition of face parts 2. Recognition of the spatial configuration of these parts
Three ways responses of a cell could be changed by attention
1. Response enhancement 2. Sharper tuning 3. Altered tuning
What are the stages of stereopsis
1. Selection of a depth plane (horopter) using vengeance eye movements and accommodation 2. Computation of binocular disparity, which provides depth information relative to the horopter
How do you build a motion detector
1. Start with two adjacent receptors 2. register change in position 3. Incorporate a delay to account for change in time
what are the four steps for subtractive color mixture?
1. Take white light that contains a broad mixture of wavelengths 2. Pass it through a filter that absorbs shorter wavelengths. The result will look yellowish 3. Pass that through a blush filter that absorbs all but a middle range of wavelengths 4. The wavelengths that make it through the filters will be a mix that looks greenish
Neural transduction of sound energy at the stereocilia
1. Tip link mechanically opens potassium channels 2. Potassium enters cell, leading to depolarization of the cell membrane 3. Depolarization opens calcium channels, causing vesicles to fuse with cell membrane and release neurotransmitters into the synaptic cleft 4. Postsynaptic button of the afferent auditory nerve gets activated by the neurotransmitter 5. Firing of auditory nerve fibers into patterns of neural activity finally completes process of translating sound waves into patterns of neural activity (sensation)
Two important features of the striate cortex
1. Topographical Mapping 2. Dramatic scaling of information from different parts of the visual field
What is the path of image processing from the eyeball to the brain?
1. eye (vertical path) photoreceptors bipolar cells retinal ganglion cells 2. lateral geniculate nucleus 3. striate cortex
Biochemical cascade caused by light
1. light hits rhodopsin in retina 2. causes the attached retinal to change form from cis to trans 3. G-protein activated (transducin) 4. transducin activates phosphdiesterase enzyme 5. The enzyme changes cGMP to GMP (cGMP is what binds/opens sodium channels to depolarize cells in the dark) 6. with less cGMP, less sodium channels open, cells becomes more negative, hyperpolarizes (potassiums equ. potential) (potassium channels always open)
Three mechanisms for cognitive habituation
1. olfactory receptors internalized into cell bodies during odor adaptation may be hindered after continuous exposure, take longer to recycle 2. Odorant molecules may be absorbed into bloodstream, causing adaptation to continue 3. Cognitive-emotional factors (healthful vs. harmful odor experiment)
Three attributes of touch receptors
1. type of stimulation the receptor responds to (pressure, temperature, pain) 2) size of the receptive field (portion of skin the receptor responds to) 3) rate of adaptation (how fast it will fatigue
Contrast Sensitivity Function peaks when?
2-4 Cycles/degree for photopic (daylight) vision, reduced for mesopic (twiglight) and scotopic (nighttime) vision
Human hearing uses a limited range of sound energy
20 to 20,000 Hz
What sound range can college aged people hear?
20-15,000Hz
What sound range can young people hear?
20-20,000Hz
What is the critical period for human vision?
3-8 years
Hypercolumn
A 1x1-mm block of striate cortex containing "all the machinery necessary to look after everything the striate cortex is responsible for, in a certain small part of the visual world" Many columns with preference for range of orientations Left and right eye Even color
Cribriform plate
A bony structure riddled with tiny holes, at the level of the eyebrows, that separates the nose from the brain Axons from OSNs pass through the tiny holes to enter the brain
Edge detector
A cell in the visual cortex that responds most to edges in the visual field.
cone-opponent cell
A cell type—found in the retina, lateral geniculate nucleus, and visual cortex—that, in effect, subtracts one type of cone input from another.
Vomeronasal organ
A chemical sensing organ at the base of the nasal cavity of many animals with a curved tubular shape evolved to detect chemicals that cannot be processed by the olfactory epithelium, such as large and/or aqueous molecules - the types of molecules that constitute pheromones
Neurotransmitter
A chemical substance used in neuronal communication at synapses
Color contrast
A color perception effect in which the color of one region induces the opponent color in a neighboring region
Color assimilation
A color perception effect in which two colors bleed into each other, each taking on some of the chromatic quality of the other
Relative size
A comparison of size between items without knowing the absolute size of either one
Illusory contour
A contour that is perceived even though nothing changes from one side of the contour to the other in the image
Object recognition should be seen as what?
A conversation among many parts of the brain rather than as a one way progression
Occlusion
A cue to relative depth order when , for example, one object obstructs the view of part of another object
Two groups of nociceptors
A delta fibers C fibers
Texture Gradient
A depth cue based on the geometric fact that items of the same size form smaller images when they are farther away Two items that are same size, the one farther away from you is perceived as smaller
Aerial Perspective
A depth cue based on the implicit understanding that light is scattered by the atmosphere more light is scattered when we look through more atmosphere more distant objects appear fainter, bluer, and less distinct
Relative metrical depth cue
A depth cue that could specify, for example, that object A is twice as far away as object B without providing information about the absolute distance to either A or B
Monocular depth cue
A depth cue that is available even when the world is viewed with one eye alone
Absolute metrical depth cue
A depth cue that provides quantifiable information about distance in the third dimension
Binocular depth cue
A depth cue that relies on information from both eyes
structural description
A description of an object in terms of the nature of its constituent parts and the relationships between those parts
Amblyopia
A developmental disorder characterized by reduced spatial vision in an otherwise healthy eye, even with proper correction for refractive error
Stereoscope
A device for presenting one image to one eye and another image to the other eye, creating a single, three-dimensional design
Absolute disparity
A difference in the actual retinal coordinates in the left and right eyes of the image of a feature in the visual scene (used for control of convergence)
Ames room
A distorted room to generate optical distance and size illusions
wave
A disturbance that transfers energy from place to place
retinitis pigmentosa
A family of hereditary diseases that involve the progressive death of photoreceptors and degeneration of the pigment epithelium
Uniqueness Constraint
A feature in the world will be represented exactly once in each retinal image
Dithering
A form of color quantization, resulting in a reduction of the number of colors needed
Efferent Copy
A form of sensory input from muscles
cupula
A gelatin-like structure containing a tuft of hairlike sensory receptor cells in the semicircular canals.
equal loudness curve
A graph plotting sound pressure level (dB SPL) against the frequency for which a listener perceives constant loudness.
Middle vision
A loosely-defined stage of visual processing that comes after basic features have been extracted from the image and before object recognition and scene understanding Involves the perception of edges and surfaces Determines which regions of an image should be grouped together into objects
Audibility threshold
A map of just barely audible tones of varying frequencies
Stereoacuity
A measure of the smallest binocular disparity that can generate a sensation of depth
Reaction time
A measure of the time from the onset of a stimulus to a response
Habituation procedure
A method for studying infant perception. After some exposure to a stimulus, an infant becomes habituated and stops paying attention to it. If the infant shows renewed interest when a new stimulus is presented, this reveals that the infant regards the new stimulus as different from the old one.
Inferior Colliculus
A midbrain nucleus in the auditory pathway
Strabismus
A misalignment of the two eyes such that a single object in space is imaged on the fovea of one eye, and on the nonfoveal area of the other (turned) eye
koniocellular cell
A neuron located between the Magnocellular and parvocellular layers of the lateral geniculate nucleus
Cone-opponent cell (or color-opponent cell)
A neuron whose output is based on a difference between sets of cones
Bandpass noise
A noise signal that contains a limited range of sound frequencies
Entorhinal cortex
A phylogenetically old cortical region that provides major sensory association input to the hippocampus. Also receives direct projections from olfactory regions
Visual field defect
A portion of the visual field with no vision or with abnormal vision, typically resulting from damage to the visual nervous system
Color-matching experiment
A procedure in which observers are asked to match the color in one field by mixing two or more lights in another field.
Belt Area
A region of cortex, directly adjacent to A1, with inputs from A1, where neurons respond to more complex characteristics of sounds
Parabelt Area
A region of cortex, lateral and adjacent to the belt area, where neurons respond to more complex characteristics of sounds, as well as to input from other senses
Lesion
A region of damaged brain To destroy a section of the brain
medial superior olive (MSO)
A relay station in the brain stem where inputs from both ears contribute to detection of the interaural time difference.
on center ganglion cell
A retinal ganglion cell that is activated when light is presented to the center, rather than the periphery, of the cell's receptive field. increases firing in response to an increase in light intensity in its receptive field center
Vertigo
A sensation of rotation or spinning
The Reichardt Motion Detector
A simple motion detection circuit proposed by Werner Reichardt Based on delay and compare fires only if signals from both detectors arrive at the comparator at the same time
Illusory conjunctions
A situation, demonstrated in experiments by Anne Treisman, in which features from different objects are inappropriately combined.
prism
A solid figure that has two congruent, parallel polygons as its bases. Its sides are parallelograms
Bayesian Approach
A statistical model based on Reverend Thomas Bayes' insight that prior knowledge could influence your estimates of the probability of a current event
random dot stereogram
A stereogram made of a large number of randomly placed dots RDSs contain no monocular cues to depth Stimuli visible stereoscopically in RDSs are cyclopean stimuli
Cue
A stimulus that might indicate where (or what) a subsequent stimulus will be: valid vs. invalid vs. neutral
Organ of Corti
A structure on the basilar membrane of the cochlea composed of hair cells and dendrites of auditory nerve fibers Movements of the cochlear partition translated into neural signals by structures in organ of corti
What advantage do sensory systems provide?
A survival advantage
Ideal observer
A theoretical observer with complete access to the best available information and the ability to combine different sources of information in the optimal manner it can be useful to compare human performance to that of an ideal observer
Absolute threshold vestibular
A tilt of less than half a minute on a clock face
Hertz
A unit of measure for frequency One hz equals one cycle per second
Decibel
A unit of measure for the physical intensity of sound Named after inventor of the telephone: Alexander Graham Bell Difference between two sounds as the ratio between two sound pressures p0 is typically based on faintest sound pressure we can hear Each 10:1 sound pressure ratio equals 20 dB, and a 100:1 ratio equals 40 dB Doubling in sound pressure corresponds to 6 dB Ratio between faintest and loudest sounds is more than 1:1,000,000
Column
A vertical arrangement of neurons. Neurons within a single column tend to have similar receptive fields and similar orientation preferences.
Afterimage
A visual image seen after the stimulus has been removed
Vestibulo-spinal responses
A whole family of reflexes that work together to keep us from falling over Without vestibulo-spinal responses, we would be unable to stand up in the dark Patients with vestibular loss actually over-compensate for body sway
Convergence
Ability of the two eyes to turn inward; reduces the disparity of the feature to zero, or near zero two eyes turning inward
Divergence
Ability of the two eyes to turn outward; reduces the disparity of the feature to zero, or near zero Two eyes turning outward
When is the fovea fully developed?
About four years old
Accidental viewpoints
Accidental co-terminations can lead to illusory depth perception due to erroneous assumptions of contiguity
otoacoustic emissions
Active amplification of sounds by the outer hair cells leads to production of sound by the ear
When do cones and rods develop and organize?
After Birth
How do you locate a sound?
All auditory signals get summed in the ear canal (Owl example) Similar dilemma to determining how far an object is two ears: critical for determining auditory locations
Striate Cortex
Also known as the primary visual cortex or V1, major transformation of visual information takes place here Consists of about 200 million cells
Binocular summation
An advantage in detecting a stimulus that is afforded by having two eyes rather than just one Two retinal images of a 3D world are not the same
Negative after image
An afterimage whose polarity is the opposite of the original stimulus light stimulus produce dark negative afterimages
parahippocampal place area (PPA)
An area in the temporal lobe that contains neurons that are selectively activated by pictures of indoor and outdoor scenes. Prefers scenes over faces or objects
Tonotopic Organization
An arrangement in which neurons that respond to different frequencies are organized anatomically in order of frequency Maintained in primary auditory cortex Neurons from A1 project to belt area, then to parabelt area
Superior Olive
An early brain stem region in the auditory pathway where inputs from both ears converge
Boundary extension
An error of committing a scene to memory in which people confidently remember seeing a surrounding region of a scene that was not visible in the studied view
rapid serial visual presentation (RSVP)
An experimental procedure in which stimuli appear in a stream at one location (typically the point of fixation) at a rapid rate (typically about eight per second).
Ponzo illusion
An illusion of size in which two objects of equal size that are positioned between two converging lines appear to be different in size. Also called the railroad track illusion.
Horopter
An imaginary surface that passes through the point of fixation. Images caused by a visual stimulus on this surface fall on corresponding points on the two retinas. The empirical location of objects whose images lie on the corresponding points The surface of zero disparity - surface in 3d space Based on actual tests of disparity (i.e., theory doesn't match reality)
Achromatopsia
An inability to perceive colors that is due to damage to the central nervous system
Problem of univariance
An infinite set of different wavelength intensity combinations can elicit exactly the same response from a single type of photoreceptor this means color discriminations cannot be based on only one type of photoreceptor
Criterion
An internal threshold set by the observer. If the internal response is above ______, the observer gives one response (e.g., "yes, I hear that"). Below ______, the observer gives another response (e.g., "no, I hear nothing")
Microsaccade
An involuntary, small, jerk-like eye movement
Texture defined object
An object that is defined by changes in contrast or texture, but not by luminance apart of second order motion
How doe we process the components in an odor mixture?
Analyses Synthesis
Feature integration Theory
Anne Treisman's theory of visual attention, which holds that a limited set of basic features can be processed in parallel preattentively, but that other properties, including the correct binding of features to objects, require attention.
parvocellular layer
Any of the top four neuron-containing layers of the lateral geniculate nucleus, the cells of which are physically smaller than those in the bottom two layers Contains the midget system and is adapted for details in static objects
Frontal Eye Field (FEF)
Area in frontal cortex that represents targets of eye movements in retinotopic coordinates
Coding of direction in the otolith organs
Arises in part from the anatomical orientation of the organ s Utricular macula: horizontal plane Saccular macula: vertical plane
Rotation perception
At first, constant rotation (in the dark) is perceived accurately Soon, however, subjects feel as if they are slowing down After 30 seconds, they no longer feel as if they are rotating time course of habituation for perceived velocity slower than time course of habituation for velocity neurons "velocity storage" when rotation stops, subjects feel as if they are rotating in the opposite direction
Identification
Attaching a verbal label to a smell is not always easy Tip-of-the-nose phenomenon
Conjunction search
Attend to multiple feature dimension Steep search slope, serial search, non-efficient search: takes twice as long to decide target absence
Internal
Attending to one line of thought over another or selecting one response over another shows up in memory retrieval
External
Attending to stimuli in the world
Covert
Attending without giving an outward sign you are doing so
Spotlight model
Attention moves from one point to the next
What are canal afferent neurons sensitive to
Back and forth rotations of the head as well greatest sensitivity to rotations at 1 Hz or less Faster rotations than 1 Hz would be dangerous Firing rate goes up and down as the head rotates back and forth the overall normalized amplitude of the canal neuron response scales with head rotation frequency
Motion parallax
Based on head movement; geometric information obtained from two eyes in different positions in the head at the same time
Bottom-up attention
Based on low-level image properties Determined by salience Automatic Fast deployment
Why are young children not very sensitive to high spatial frequencies?
Because their visual system is still developing
Where is a large proportion of processing done in the auditory system?
Before A1
What we smell can affect what we see (Zhou et al., 2010)
Binocular rivalry stimulus of markers in one eye and rose in the other Subjects switch back and forth between seeing one or the other stimulus When the smell of markers or roses was presented to their nostrils, subjects saw the corresponding stimulus more often
olfactory bulb
Blueberry-sized extension of the brain just above the nose, where olfactory information is processed There are two olfactory bulbs, one in each brain hemisphere, corresponding to the left and right nostrils. Connections are ipsilateral (Same side of the body) Unlike vision, hearing or touch, which are contralateral
Genetic basis of olfactory receptors
Buck and Axel (1991): Genome contains about 1000 different olfactory receeptor genes; each codes for a single type of OR All mammals have pretty much the same set of 1000 genes. However, some genes are non-functional pseudogenes Dogs and mice: About 20% are pseudogenes Humans: Between 60-70% are pseudogenes Each person has a different number of pseudogenes, resulting in individual differences in sensitivity to smells There may be an evolutionary trade-off between vision and olfaction
How is strabismus treated?
By patching the dominant eye
How is attention deployed?
By things you know (your own decisions, biases, knowledge, etc) Things you see (which items are most salient, unique,e tc.
How does Escher fool us with his drawings?
Cannot sort out the perception of space in his drawings
texture segmentation
Carving an image into regions of common texture properties
simple cells
Cells in V1 that respond to line, or gradient, oriented in particular direction Phase sensitive
Complex Cells
Cells in V2 that give best response to moving lines of particular orientation Do not have clearly defined excitatory and inhibitory regions Phase insensitive Respond to bar, regardless of exact positioning within receptive field
Photoreceptors
Cells in the retina that initially transduce light energy into neural energy (100 million in each eye)
frequency selectivity
Clearest with very faint sounds
Sour
Comes from acidic substances At high concentrations, acids will damage both external and internal body tissues Hydrogen ions inside the receptor cell trigger sour perception many people like sour in low concentrations
Do we use optic flow information?
Computer-generated displays of moving dots and lines to stimulate optic flow information Humans can detect differences in heading of 1 degree of visual angle only with optic flow
How are the circular receptive fields in the LGN transformed into the elongated receptive fields in striate cortex?
Concentric LGN cells that feed into a cortical cell are all in a row
Saccule
Contains about 16,000 hair cells
Sustained
Continuously monitoring some stimulus
Nonselective pathway
Contributes information about the distribution of features across a scene as well as information about the "gist" of the scene. This pathway does not pass through the bottleneck of attention
What happens in the sensory homunculus
Correspondence between pattern of two-point thresholds across body and relative distortion of different body parts in sensory homunculus sufficient concentration of receptors at the skin, each with small enough receptive field, that two contact points will elicit different responses
Ian Waterman
Cutaneous nerves connecting Waterman's kinesthetic mechanoreceptors to brain destroyed by viral infection Waterman lacks kinesthetic senses, which initially prevented him from walking or making virtually any motion. He has learned to imagine his movements and use his vision to help position his limbs.
Common hearing loss
Damage to hair cells due to excessive exposure to noise
Analgesia
Decreasing pain sensation during conscious experience Soldiers in battle: experience pain-relieving effect because of endogenous opiates, chemicals released in body to block release or uptake of neurotransmitters transmitting pain sensations to brain Externally produced substances have similar effect: Morphine, heroin, codeine
HSB color space
Defined by hue, saturation, and brightness - used in graphics design
Macular degeneration
Degeneration of the "macula": central vision, sharp details Loss in central vision --> blindness 1:3500 Canadians Typically leads to legal blindness by age 40 Caused by the formation of new veins or thinning of tissue. Rods die off first, leading to decay of cones
McGurk Effect
Demonstrates the cross-modal combination of auditory and visual information for speech perception Perception of onset consonants is determined by a combination of visual and auditory cues errors in binding can lead to illusory perception of consonants
Top-Down attention
Dependent on prior knowledge or task Determined by behavioral relevance Volition controlled Slower deployment
Directional transfer function
Describes how pinnae, ear canal, head, and torso change intensity of sounds with different frequencies that arrive at each ear from different locations in space (azimuth and elevation)
Gate control theory
Description of the system that transmits pain that incorporates modulating signals from the brain Feedback circuit located in substantia gelatinosa of dorsal horn of spinal cord Gate neurons that block pain transmission can be activated by extreme pressure, cold, other noxious stimulation applied to another site distant from source of pain
How do senses form in the environment?
Determined by the type of energy present in the environment
Staircase method
Determining concentration required for detection stimulus is presented in increasing concentrations until detection is indicated concentration is decreased until detection ceases repeated and reversals are averaged to determine threshold detection level
Shape pattern theory
Different scents activate different arrays of olfactory receptors in the olfactory epithelium as a function of odorant-shape to OR-shape fit These various arrays produce specific firing patterns of neurons in the olfactory bulb, which then determine the particular scent we perceive
Attentional blink
Difficulty in perceiving and responding to second of two target stimuli amid a RSVP stream of distracting stimuli
Overt
Directing a sense organ toward a stimulus, like pointing your eyes or turning your head
Sense of smell and language:
Disconnected, possibly because: Olfactory information is not integrated in thalamus prior to processing in cortex. Majority of olfactory processing occurs in right side of brain while language processing occurs in left side of brain.
Arthur Fox (1931)
Discovered that phenylthiocarbamide (PTC) tastes dramatically different to different people Bitter taste to some but not to others 1960s: started using propylthioracil (PROP) instead of pTC because it is safer Gene for PTC/PROP receptors discovered in 2003 individuals with two recessive genes are nontasters of PTC/PROP Individuals with one or more of the genes are tasters of PTC/PROP
Uncrossed disparity
Disparity created by objects behind the plane of the horopter images behind the horopter are displaced to the right eye and to the left in the left eye
Crossed disparity
Disparity created by objects in front of the plane of the horopter images in front of the horopter are displaced to the left in the right eye and to the right in the left eye
First-Order Motion
Displacement can be several degrees ISI can be as large as 500 msec Presentations can be monotopic or dicoptic Displaced patterns can have different contrasts Does not produce aftereffects
Second-Order motion
Displacement must be less than 1/4 degree ISI must be less than 100 msec Presentations must be monoptic Displacement patterns must have the same contrast Produces aftereffects
Autostereoscopic (3D)
Does not require any head gear
Protanopia
Due to absence of L cones
Tritanopia
Due to absence of S cones
Deuteranopia
Due to the absence of M cones
Why considered different "modalities" ?
Each involve different receptors and/or different stimulation energy
Two examples of "Simple Cells"
Edge detector and Stripe Detector
Ruffini Endings (SA II)
Embedded deeply in the dermis Responds best to sustained downward pressure and lateral skin stretch Responds to finger position and grasp Slowly adapting (SA II) Large receptive field size When stimulated people experience no tactile sensation. More than one SA II fiber need to be stimulated in order to be detectable
Pacinian Corpuscles (FA II)
Embedded in subcutaneous tissue Respond best to high frequency vibrations of 50-700 Hz Active when object makes first contact with skin, e.g. mosquito landing on skin, hitting key on keyboard Fast adapting (FA II) Large receptive field size When electrically stimulated, people report "buzz"
reflected
Energy that is redirected when it strikes a surface, usually back to its point of origin
synthesis
Example from color mixtures. Mixing red and green lights results in yellow light but we cannot separately perceive the red and green in the yellow
How do we know that listeners hear a sound as continuous?
Experiments that use signal detection task (e.g. Kluender and Jenison) suggest that at some point restored missing sounds are encoded in brain as if they were actually present
Smooth pursuit
Eye move smoothly to follow moving object (as with the pencil and dot demo)
Bottom-up
Factors from the world e.g. Looking for red and white to find Waldo
Top-down
Factors from you e.g. looking for waldo you won't look at the trees because people do not climb trees
V4 cells are interested in what?
Fans, spirals, and pinwheels
Correspondence Problem
Figuring out which bit of the image in the left eye should be matched with which bit in the right eye
Good continuation
Filling in of missing parts of sounds
Inner Ear
Fine changes in sound pressure are translated into neural signals Function roughly analogous to that of retina
Primary auditory cortex (A1)
First area within the temporal lobes of the brain responsible for processing acoustic organization
Cochlear nucleus
First brain stem nucleus at which afferent auditory nerve fibers synapse
Sir Alan Hodgkin and Sir Andrew Huxley
First scientists to record squid neurons
How would we identify a dog using categorization
First: Identify the superordinate animal Then we would identify the basic level which would be dog Then we would identify the subordinate level which is golden retriever And finally we would attribute an identity to the subordinate level which would be mr. Snuffles
Electrical stimulation of MT neurons (Newsome et al.)
Found direction sensitive MT neurons Stimulated them electrically while dots moved in nonpreferred direction Results: monkeys saw motion in the neurons preferred direction even when it was opposite to the direction of moving dots Conclusion: MT cells are global-motion detection area
Hubel and wiesel
Found systematic and progressive change in preferred orientation All orientations were encountered in a distance of about 0.5mm Same orientation preference in columns perpendicular to the surface of cortex
Common fate
Group elements in the same direction together
Proximity
Group things together that are closer together
Similarity
Grouping by timbre or by similar pitch
Push pull symmetry
Hair cells in opposite ears respond in a complementary fashion to each other When hair cells in the left ear depolarize, those in the analogous structure in the right ear hyperpolarize
Stereocilia
Hairlike extensions on the tips of hair cells in the cochlea that initiate the release of neurotransmitters when they are flexed
Cilia
Hairlike protrusions on the dendrites of OSNs. Contain receptor sites for odorant molecules. These are the first structures involved in olfactory signal transduction
Rod monochromat
Have no cones of any type; truly color-blind and badly visually impaired in bright light
Cone monochromat
Have only one cone type; truly color blind
Color-anomalous
Have two types of cones (typically L- and M-cones) which are so similar that they can't make discriminations based on them
What is one of the natural consequences of aging?
Hearing loss
What kind of frequency is absorbed?
High frequencies
Are more distant objects higher or lower in the visual field?
Higher
Spectral composition of sounds
Higher frequencies decrease in energy more than lower frequencies as sound waves travel from source to one ear (low frequencies travel farther)
Restoration of complex sound (E.g. music, speech)
Higher order sources of information, not just auditory information ECoG study: novel vs. nozzle presented as novel
Recent Human evidence suggests
Human olfaction is actually pretty good Elephants have 2000 ORs vs. Humans 400 Humans can track smells use odor to navigate, even out smell a mouse Humans need more molecules to smell whereas dogs need less
What has research shown when it comes to determining differences in sounds between two things
Humans are good at detecting small differences in frequency (as little as 1Hz between 999 Hz and 1kHz)
Yaw rotation thresholds
Humans are so sensitive to yaw rotation that we can detect movements of less than 1 degree per second At this rate, it would take 6 minutes to turn completely around As yaw rotation frequency decreases, it takes faster movement to be detected
Odor imagery
Humans have little or no ability to conjure odor "images" We do not think in smell very well We do not imagine smells very well - dreams with olfactory sensations are very rare Other animals for whom smell plays a more central role, such as rats, may very well think an dream smells...
Absorption
If Pigments A and B mix, some of the light shining on the surface will be subtracted by A, and some by B. Only the remainder contributes to the perception of color What remains is what is reflected
Illusion involving tilt perception
If you roll tilt your head to the left or right while looking at a vertical streak of light, the light appears to tilt in the opposite direction
Passive 3D
Images for the left and right eye are shown at the same time with differently polarized light Cheap passive glasses with polarization filters separate the images for the left and right eye Used in some 3D TVs and 3D cinema
Active 3D
Images for the left and right eye are shown in alternation Active shutter glasses block the view of the right and left eye in sync with the display used in some 3D Tvs
Pop-out or Parallel search
Immediate perception of oddball target, independent of set size
Why do we need attention?
Impossible to handle all sensory inputs at once. nervous system has evolved mechanisms to restrict processing to a subset of things, places, ideas, or moments
Coding of amplitude in the semicircular canals
In the absence of any rotation, many afferent neurons from the semicircular canals have a resting firing rate of about 100 spikes/s. This firing rate is high relative to nerve fibers in other sensory systems. High firing rate allows canal neurons to code amplitude by decreasing their firing rate, as well as increasing it. Changes in firing rate are proportional to angular velocity of the head aligned with the canal the neuron is in.
Suppression
In vision, the inhibition of an unwanted image
Neglect
Inability to attend to or respond to stimuli in the contralesional visual field (i.e. side opposite of brain lesion). typically after right parietal damage, leading to the inability to attend to one's left visual field
Tactile agnosia
Inability to identify objects by touch Caused by lesion to the parietal lobe (S1 and s2) Patient documented by Reed and cASELLI (1994) Could recognize weight and roughness on either hand Same sensory thresholds on both hands (how firm, how much motion, how much heat, etc.) But lacked a connection between sensation and recognition systems on the impaired side: Unable to integrate perceived properties about objects
Inanimate agnosia
Inability to recognize inanimate objects
end stopping
Increased firing rate as bar length increases, but once longer than receptive field, firing rate decreases
How do we estimate the time to collision of an approaching object?
Information source: Tau; It relies on information from retinal image -- need to track visual angle subtended by approaching object as it approaches the eye Not clear if we actually make use of tau, but: Humans are best at paying attention to the focus of expansion
How is stereopsis implemented in the human brain?
Input from two eyes must converge onto the same cell Many binocular neurons respond best when the retinal images are on corresponding points in the two retinas: Neural basis for the horopter However, many other binocular neurons respond best when similar images occupy slightly different positions on the retinas of the two eyes (tuned to particular binocular disparity)
ISI
Interstimulus Interval
What are the disadvantages of using lesion studies to study motion?
Invasive Lesions may be incomplete or may influence other structures
Contrast Sensitivity
Inverse of contrast threshold, e.g.: 1000-990 photons 1/0.01 = 100
Recognition-by-components (RBC) model
Irving Biederman proposed that objects are recognized by the identities and relationships of their component parts, called geons
How does image inversion affect facial recognition?
It hurts facial recognition more than object recognition
What happens when the IT cortex is lesioned?
It leads to agnosias in spite of the ability to see
What does adaptation provide strong evidence for with regards to spatial frequency?
It provides strong evidence that orientation and spatial frequency are coded by neurons in the human visual system
Which direction does the pathway for object recognition run?
It runs in both directions
Self-terminating search
Items examined one after another until target is found (target present) or until all items are checked (target absent)
mantis shrimp
Known for its amazing color perception with over 16 different photoreceptors 12 of those dedicated to color vision They can also see UV and long red wavelengths
Total stimulation of M cone is equal to Total stimulation of what?
L cone
Coding of amplitude in the otolith organs
Larger accelerations (or larger gravitation shear forces) move the otoconia more This leads to greater deflection of the hair cell bundles Change in receptor potential is proportional to magnitude of linear acceleration or gravitational shear
Physiology of ILDs
Lateral superior olives are neurons that are sensitive to intensity differences between two ears Excitatory connections to LSO come from ipsilateral (same side) ear inhibitory connections to LSO come from contralateral (opposite side) ear ILD works best for high frequencies...why?
Blurring the image
Leaving only the low-spatial frequency information (Reduces the number of blobs to match)
Photopic
Light intensities bright enough to stimulate cone receptors and bright enough to "saturate" the rod receptors Sunlight and bright indoor lighting are both photopic lighting conditions
The special case of fat
Like protein, fat is an important nutrient. Fat molecules evoke tactile sensations like oily, viscous, creamy, etc. Rats have fatty acid receptors on their tongues and humans may, too. Digesting fat in the gut produces conditioned preferences for the sensory properties of the food containing fat. New research says humans also have fat receptors
Merkel Cell Neutrite complex (SA I)
Located at boundary between epidermis and dermis Responds best to steady downward pressure Small receptive field size Used to detect fine spatial detail Sensitive to very low frequency of vibrations (< 5Hz) Slowly Adapting (SA I) Important for texture and pattern perception, e.g. for Braille reading or to determine the orientation of a screw head without looking When nerve is electrically stimulated, people report feeling "pressure"
Meissner Corpuscles (FA I)
Located at boundary between epidermis and dermis Sensitive to low frequency vibrations between 5 Hz and 50 Hz Fast adapting (FA I) Small receptive field size Important to detect slip of objects across skin, e.g. to correct grip around object When stimulated electrically, people feel "wobble" or "flutter"
Visual search
Looking for a target in a display containing distracting elements Target: the goal of visual search distractor: any stimulus other than the target Set size: the number of items in a visual display
Processes in object recognition
Low-level vision (Determine features present in image) Middle vision (Group features into objects) High-level vision (Match perceived to encoded representations)
Red+Blue
Magenta
Rate Intensity function
Map plotting firing rate of auditory nerve fiber in response to a sound of constant frequency at increasing intensities
Threshold tuning curve
Map plotting thresholds of a neuron or fiber in response to sine waves with varying frequencies at lowest intensity that will give rise to a response
Yarbus experiment
Mapped where people looked at an image and found that the eyes spent the most time looking at the eyes and mouth
Locating the haptic egocenter
Match the location of the right hand on top of the surface with the left hand on the bottom Results: Consistently err to the right - egocenter close to right shoulder change hands: egocenter appears to be at left shoulder
Method of Adaptation
Measuring the diminishing response of a sense organ to a sustained stimulus (without poking the brain)
Physiology of ITD
Medial superior olives are the first place where input converges from two ears ITD detectors form connections from inputs coming from two ears during first few months of life
Pleasant Touch
Mediated by unmyleniated peripheral C fibers known as "C tactile afferents" CT afferents not related to pain or itch Respond best to slowly moving, lightly applied forces (e.g. petting) Processed in orbitofrontal cortex (pleasure, reward)
Absolute Threshold
Minimum amount of stimulation necessary for a person to detect a stimulus 50% of the time
Are receptive fields for extra striate area cells more sophisticated or less sophisticated than V1 cells?
More sophisticated than V1 cells
Subordinate-level category
More specific term for an object
sensorineural hearing loss
Most serious auditory impairment. Due to defects in cochlea or auditory nerve; when hair cells are injured ( e.g as result of ototoxic antibiotics or cancer drugs)
What do cortical cells respond well to?
Moving lines, bars, edges, gratings, and direction
Volley Principle
Multiple AN neurons can provide a temporal code for frequency if each neuron fires at a distinct point in the period of a sound wave but does not fire on every period
Fungiform papillae
Mushroom-shaped structures (maximum diameter 1 mm) that are distributed most densely on the edges of the tongue, especially the tip. An average of six taste buds per papilla are buried in the surface
Identity
Name for a specific object
Tipper and Behrmann's experiment on world vs. object based neglect:
Neglect can be object-based
Semicircular canal dynamics
Neural activity in semicircular canals is sensitive to changes in rotation velocity. Constant rotation leads to decreased responding from the canal neurons after a few seconds.
Topographical mapping
Neural basis for knowing where things are located in space (i.e., specific neural architecture for distinct locations in our visual field)
Why are we not bothered by variations in overall light levels?
Neural circuitry
Primary olfactory cortex
Neural region where olfactory information is first processed. Includes amygdala, parahippocampal gyrus, and entorhinal cortex
lateral superior olives
Neurons that are sensitive to intensity differences between two ears
Is speech an old or new structure
New structure in the cortex (Recent in evolution)
Do the vestibular organs respond to constant velocity?
No
is object recognition completely viewpoint invariant
No
Can each LGN cell respond to more than one eye?
No, it can only respond to one eye never both
Pain sensitization
Nociceptors provide signal when there is impending or ongoing damage to body's tissue "Nociceptive" pain Once damage has occured site can become more sensitive: Hyperalgesia Pain as result of damage to or dysfunction of nervous system: neuropathic No single pain medication will alleviate all types of pain
Dizziness
Nonspecific spatial disorientation
Is there a cortex for the vestibular system?
Not really areas of cortex respond to vestibular input as well as visual input
Pathway of nerves to cortex
Nucleus of the solitary tract in the brain stem, thalamus, cortex (insula, orbitofrontal)
Nonaccidental feature
Object feature not dependent on the exact (or accidental) viewing position of the observer. Provides clues to object structure (e.g. T junctions and occlusions)
Relative Height
Objects at different distances from the viewer on the ground plane will form images at different heights in the retinal image
The feel of scent
Odorants can stimulate somatosensory system through polymodal nociceptors (touch, pain, temperature receptors) These sensations are mediated by the trigeminal nerve (cranial nerve V) Often, it is impossible to distinguish between sensations travelling up cranial nerve I from olfactory receptors and those traveling up cranial nerve V from somatosensory receptors e.g.: peppermint - cool, ammonia, burning
Ternus effect
One circle appears to jump over a stationary circle in the center. Because the center circle remains perfectly stable it is not a possible candidate for apparent motion Identical to the previous one except a brief blank frame added between the two apparent motion frames. Display now perceived as two dots moving as a group
How do you measure visual acuity?
Optometrists use distance (e.g. 20/20; 6/6) Vision scientists use the smallest visual angle of a cycle of a grating
RGB
Outputs of long (red), medium (green), and short (blue) wavelength lights (monitors, projectors)
Alternating columns of pixels are projected into the two eyes using what?
Parallax barrier and lenticular arrays
Parallelism
Parallel contours are likely to belong to the same figure
Euclidian geometry
Parallel lines remain parallel as they are extended in space objects maintain the same size and shape as they move around in space internal angles of a triangle always add to 180 degrees
Decay (sound)
Part of a sound during which amplitude decreases (offset)
Matching
Participants are tilted and then orient a line with the direction of gravity. This is done in a dark room with only the line visible to avoid any visual cues to orientation
What happens when we cannot perceive taste but we can perceive smell?
Patient case: damaged taste, but normal olfaction -- could smell lasagna, but had no flavor similar effect created in lab: chorda tympani anesthetized with lidocaine
retronasal olfaction
Perceiving odors through your mouth while breathing and chewing. This occurs when we are smelling something that is inside our mouth and is what gives us the experience of flavor.
tilt aftereffect
Perceptual illusion of tilt, provided by adapting to a pattern of a given orientation suggests human visual system contains individual neurons selective for different orientations
Selective pathway
Permits the recognition of one or a very few objects at a time The pathway passes through the bottleneck of selective attention
Temporal code for sound frequency
Phase Locking: Neuron fires only at a distinct point in the period (Cycle) of sound wave at given frequency AN fibers fire with a temporal code
Cones
Photoreceptors that are specialized for daylight vision, fine visual acuity and color
Kinesthetic receptors
Play important role in sense of where limbs are, what kinds of movements are made spindles, receptors in tendons, and receptors in joints
Phase
Position of grating within a receptive field
What are two ways to study the vision of infants?
Preferential-looking paradigm Visual evoked potentials
Gestalt grouping rules
Principles for grouping the seemingly
Temporal integration
Process by which a sound at a constant level is perceived as being louder when it is out of greater duration
Reflectance Curve
Proportion of light at different wavelengths that is reflected from a pigment
The vestibular organs help us in many ways, for instance:
Provide a sense of spatial orientation Linear motion Angular motion Tilt Allow for the vestibulo-ocular reflex Stabilizes visual input by counter rotating the eyes to compensate for head movement
Nonmetrical
Provides information about the depth order (relative depth) but not depth magnitude (e.g. his nose is in front of his face)
Metrical
Provides quantitative information about distance in the third dimension (e.g. the tip of his nose is 3.2 cm from his cheek)
What physical property is color?
Psychophysical
Reaction time benefit of the cue
RT (invalid) - RT (valid)
The efficiency of visual search is the average increase in
RT for each item added to the display
Saccade
Rapid movement of eyes that change fixation from one object or location to another
Cyclopean
Referring to stimuli that are defined by binocular disparity alone
Contralateral
Referring to the opposite side of the body/brain
Dichoptic
Referring to the presentation of two stimuli one to each eye. Different from binocular presentation, which could involve both eyes looking at a single stimulus
Extra striate cortex
Region of cortex bordering the primary visual cortex and containing multiple areas involved in visual processing Respond to visual properties important for perceiving objects
Parallelism
Regions with parallel contours tend to be seen as figure
Simplest Cue
Relative intensity of sound
Categorical perception of consonants (onsets)
Researchers can manipulate sound stimuli to vary continuously from "bah" to "dah" to "gah" People perceive sharp categorical boundaries between the stimuli instead of perceiving sounds as continuously varying
Parahippocampal place area
Responds preferentially to places, such as pictures of houses or landscapes
Fusiform face area
Responds to faces more than other objects
Auditory Nerve
Responses of individual auditory nerve fibers to different frequencies related to position along cochlear partition
LMS
Responses of the three types of cones
S1 and S2
Responsible for sensory aspects of pain
What does interocular transfer tell us about the locus of the MAE in the visual system?
Result of activities of neurons in a part of the visual system where information collected from two eyes is combined Input from both eyes is combined in area V1 Recent studies: localized motion aftereffects to MT
Motion sickness
Results when there is a disagreement between the motion and orientation signals provided by the semicircular canals, otolith organs, and vision
How do we recognize objects?
Retinal ganglion cells and LGN = Spots Primary Visual Cortex = Bars
What does S1 connect to
S2
David Hubel and Torsten Wiesel
Sensation and perception; Discovered feature detectors, groups of neurons in the visual cortex that respond to different types of visual stimuli Their experiment was performed on a cat
Thermoreceptors
Sensory receptors that signal information about changes in skin temperature Two distinct populations of thermoreceptors: warmth fibers, cold fibers
Nociceptors
Sensory receptors that transmit information about noxious (painful) stimulation that causes damage or potential damage to the skin Two groups of nociceptors
Gunnar Svaetichin
Showed the existence of three different cone types with different sensitivity to wavelength in 1956
Inverse-square law
Sound intensity decreases with 1/d2 with increasing distance d in 3D space
Outer ear
Sounds are first collected from the environment by the pinnae sound waves are funnelled by the pinna into ear canal length and shape of ear canal enhance sound frequencies main purpose of canal is to protect the tympanic membrane (eardrum)
Summerfield experiment
Sounds with holes in the spectrum, presented right before a uniform spectrum. The uniform spectrum is heard as a vowel
What happens when vestibular system fails?
Spatial disorientation Imbalance Distorted vision unless head is held perfectly still Motion sickness Cognitive problems
Problems that can arise from the vestibular system
Spatial disorientation dizziness Vertigo Imbalance Blurred vision Illusory self-motion
Middle Temporal Area (MT)
Specialized for motion processing
Extrastriate Body Area (EBA)
Specifically involved in the perception of body parts
Glomeruli
Spherical conglomerates containing the incoming axons of the OSNs Each OSN converges on two glomeruli (one medial, one lateral)
Cochlea
Spiral structure of inner ear containing the organ of corti filled with water fluids in three parallel canals vestibular canal: oval window to helicotrema Tympanic canal: round window to helicotrema middle canal: contains the cochlear partition
Divided
Splitting attention between two different stimuli
SOA
Stimulus Onset Asynchrony
Exotropia
Strabismus in which one eye deviates outward
tip links
Structures at the tops of the cilia of auditory hair cells, which stretch or slacken as the cilia move, causing ion channels to open or close. open potassium channels leading to depolarization
Pigments
Substances that absorb light at some wavelengths and reflect light at others
Five relational violations according to Biederman et al. (1982)
Support Interposition Probability Position Size
Three types of cells
Supporting cells Basal cells olfactory sensory neurons
Mal de Debarquement Syndrome
Swaying, rocking, or tilting perceptions felt after spending time on a boat or in the ocean Aftereffect of adapting to the rocking motion of the ocean "Getting your sea legs" Usually goes away after a few hours, but some people experience it continuously, causing problems
Symmetry
Symmetrical regions are more likely to be seen as figure
DCML
Synapse in cuneate and gracile nuclei, then ventral posterior nucleus of thalamus then somatosensory area 1 (S1), somatosensory area 2 (S2) Wider axons fewer synapses faster information transmission used for planning and execution of fast movements
Symbolic (Endogenous) cue
Target location derived indirectly from shape or color of cue
Adam Magyar
Techno artist and photographer who uses a special scanning technique to combine thousands of pixel-wide slices into a single image He confouds time and space in his images Motion parallax clearly visible
Deep learning computer vision models
Template (view-based) theory Massive set of increasingly complex features Works amazing well Matches neural representations in visual brain areas
Closure
Tendency to see complete figures or forms even if a picture is incomplete, partially hidden by other objects
Apparent motion
The (illusory) impression of smooth motion resulting from the rapid alternation of objects appearing in different locations in rapid succession First demonstrated by Sigmund Exner in 1875 Motion detector circuit does not need real motion in order to fire The basis for flop books, movies, TV
Vanishing point
The apparent point at which parallel lines receding in depth converge
fundus
The back layer of the retina—what the eye doctor sees through an ophthalmoscope.
Receptor Adaptation
The biochemical phenomenon that occurs after continuous exposure to an odorant, whereby the receptors stop responding to the odorant and detection ceases
Hue
The chromatic (Color) aspect of light
Pupil
The dark circular opening at the center of the iris in the eye, where light enters the eye
interaural level difference (ILD)
The difference in level (intensity) between a sound arriving at one ear versus the other
Interaural time difference (ITD)
The difference in time between a sound arrive at one ear versus the other
Binocular disparity
The differences between two retinal images of the same scene Differences as small as .005mm can be detected
Empiricism
The idea that all knowledge comes through the senses
Level of response depends on what when talking about cones?
The level of response depends on lighting conditions
olfactory sensory neurons (OSNs)
The main cell type in the olfactory epithelium OSNs are small neurons located beneath a watery mucous layer in the epithelium We have approximately 5-10 million OSN. Only vision has more sensory neurons (photoreceptors)
Nativism
The mind produces ideas that are not derived from external sources, and that we have abilities that are innate and not learned
Two-point threshold
The minimum distance at which two stimuli (e.g. two simlutaneous touches) are just perceptible as separate
Angular VOR
The most well-studied VOR example when the head turns to the left, the eyeballs are rotated to the right to partially counteract this motion
Second order motion
The motion of an object that is defined by changes in contrast or texture, but not by luminance
Medial geniculate nucleus
The part of the thalamus that relays auditory signals to the temporal cortex and receives input from the auditory cortex
trichromacy
The perceived color of any light is defined in our visual system by the relationships between a set of three numbers, the outputs of three receptor types now known to be the three cones
Missing-fundamental effect
The pitch listeners hear corresponds to the fundamental frequency, even if it is missing
Correspondence problem (motion)
The problem faced by the motion detection system of knowing which feature in frame 2 corresponds to a particular feature in frame 1 There are a wide variety of Gestalt principles that can influence the brain's solution to the correspondence problem: 1. proximity 2. color 3. shape
Preattentive stage
The processing of a stimulus that occurs before selective attention is deployed to that stimulus (automatically)
Global superiority effect
The properties of the whole object take precedence over the properties of parts of the object (e.g. Navon letters)
Naive template theory
The proposal that the visual system recognizes object by matching the neural representation of the image with a stored representation of the same "shape" in the brain
blood oxygen level-dependent (BOLD) signal
The ratio of oxygenated to deoxygenated hemoglobin that permits the localization of brain neurons that are most involved in a task
Cross Adaptation
The reduction in detection of an odorant following exposure to another odorant presumed to occur because the two odors share one or more olfactory receptors for their transduction, but the order of odorants also plays a role
Receptive Field
The region in space in which stimuli will activate a neuron
Olfactory Receptor (OR)
The region on the cilia of OSNs where odorant molecules bind It takes seven or eight odor molecules binding to a receptor to initiate an action potential It takes about 40 such events to perceive an odor
Although the eyeball is mostly similar to how a camera functions, how isn't the eyeball similar?
The resemblance stops at the retina where transduction occurs. However, the regulation of the amount of light and the lens for adjusting focal length for viewing near and far objects are similar to that of a camera
Sensation
The result of physical interaction between the world and our bodies
Size
The smaller region is likely to be figure
Cristae
The specialized detectors of angular motion located in each semicircular canal in a swelling called the ampulla Each crista has about 7000 hair cells, associated supporting cells, and nerve fibers Cilia of hair cells project into jellylike cupula which forms an elastic dam extending to the opposite ampulla wall, with endolymph on both sides of the dam
Psychoacoustics
The study of the psychological correlates of the physical dimensions of acoustics; a branch of psychophysics
Surroundedness
The surrounding region is likely to be ground
Vieth-Muller circle
The theoretical location of objects whose images fall on geometrically corresponding points in the two retinas in the horizontal plane. Circle that intersects the objects and the lenses of both eyes. Based on geometry of location of eyes
Opponent color theory
The theory that perception of color is based on the output of three mechanisms, each of them based on opponency between two colors
Trichromacy
The theory that the color of any light is defined in our visual system by the relationships of three numbers, the outputs of three receptor types now known to be the three cones
Semicircular canals
The three toroidal tubes in the vestibular system that sense angular acceleration, a change in angular velocity each one is about 3/4 of a toroid (donut) shape, measuring 15mm long and 1.5mm in diameter Canals are filled with a fluid called perilymph A second smaller toroid is foiund inside the larger toroid, measuring 0.3mm in diamter Formed by a membrane filled with fluid called endolymph cross section of each canal swells substantially near where the canals join the vestibule: ampulla
cornea
The transparent "window" into the eyeball (No blood vessels, has nerves)
vitreous humor
The transparent fluid that fills the vitreous chamber in the posterior part of the eye 80% of the volume of the eye
Aqueous humor
The watery fluid in the anterior chamber
How are human senses limited?
They are limited to only certain kinds of energy in the environment
Why does an oriented grating appear to be gray if you are far enough away?
This striped pattern is a "sine wave grating"; the visual system "samples" the grating discretely
Coding of direction in the semicircular canals
Three semicircular canals in each ear Each canal is oriented in a different plane Each canal is maximally sensitive to rotations perpendicular to the canal plane
Three experimental paradigms are typically used to investigate spatial orientation perception
Threshold estimation, magnitude estimation, matching
Tadoma method of speech perception for deaf and blind people
Thumb on speaker's lips, fingers along the jawline, little finger feels vibrations of the throat Invented by American teacher Sophi Alcorn Named after the first two children who used the method: Winthrop "Tad" Chapman and Oma Simpson
Stimulus onset asynchrony (SOA)
Time between the onset of one stimulus and the onset of another
Cochlear implants
Tiny flexible coils with miniature electrode contacts Surgeons thread implants through round window toward cochlea apex Tiny microphone transmits radio signals to a receiver in the scalp Signals activate minature electrodes at appropriate positions along the cochlear implant Activated electrodes stimulate the auditory nerves
Anosmia
Total inability to smell, most often resulting from sinus illness or head trauma A hard blow to the front of the head can cause the cribriform plate to be jarred back or fractured, slicing off the fragile olfactory neurons Anosmia also causes a profound loss of taste can lead to depression, loss of libido Anosmia can be an early signal for the onset of Alzheimer's or Parkinson's Disease
Jack Loomis experiment
Touch acts like blurred vision when the fingertips explore a raised pattern 1. Visual stimuli blurred to match the acuity of fingertip skin 2. Visual stimuli and haptic stimuli showed same confusion errors
Thomas Young and Hermann von Helmholtz
Tri-chromatic theory/tri-color/component theory
Two caveats for theory that odor hedonics are mostly learned
Trigeminally irritating odors may elicit pain responses, and all humans have an innate drive to avoid pain There is potential variability in receptor genes and pseudogenes that are expressed across individuals
Opponent Reichardt Motion Detector
Two Reichardt detectors tuned to opposite directions of motion. Outputs are subtracted from one another.
Common region
Two features will group if they appear to be apart of the same larger region
Connectedness
Two items will tend to group if they are connected
How many steps does face perception proceed in?
Two steps
Binding
Tying multiple features of a stimulus to a unified object requires attention
Middle Ear
Tympanic membrane is border between outer ear (ear canal) and middle ear consists of three tiny bones, ossicles that amplify sounds Ossicles
Vergence eye movement
Type of eye movement in which two eyes move in opposite directions, done deliberately for spatial vision
How finely can we resolve temporal details?
Typical resolution found 5ms Common psychophysical method: decide whether two events are simultaneous or sequential This is better than vision (25ms) but worse than audition (0.01ms)
Harmonic Spectra
Typically caused by simple vibrating source (e.g. string of guitarm or reed of saxophone) fundamental frequency
Anamorphosis (or anamorphoic projection)
Use of rules of linear perspective to create a two dimensional image so distorted that it looks correct only when viewed from a special angle or with a mirror that counters the distortion Opposite of the accidental viewpoint
Landolt Rings (or "Cs")
Used in most European countries, a way to determine visual acuity that does not involve the prior knowledge of letters
Azimuth
Used to describe locations on imaginary circle that extends around us, in a horizontal plane
Masking
Using a second sound, frequency noise, to make the detection of another sound more difficult; used to investigate frequency selectivity
How is stereoacuity often tested
Using dichoptic stimuli
What is S1 equivalent to
V1 in vision or A1 in hearing
Why don't people feel as if they are turning upside down
Vestibular system's sense of gravity stops the illusion Astronauts without gravity feel as if they are tumbling under these circumstances Thus vestibular information is combined with visual information to yield a "consensus" about our sense of spatial orientation
Ambiguous Figure
Visual stimulus that gives rise to two or more interpretations of its identity or structure
What experiments demonstrated the cone of confusion
Wallach (1940)
Detection
Wavelengths of light must be detected in the first place
Tilt Perception
We are very accurate when perceiving tilt for angles between 0 degrees (upright) and 90 degrees (lying down)
Discrimination
We must be able to tell the difference between one wavelength (or mixture of wavelengths) and another
Appearance
We want to assign perceived colors to lights and surfaces in the world and have those perceived colors be stable over time, regardless of different lighting conditions
What does 20/20 vision mean?
What a person with perfect vision can see at 20 feet, you can also see at 20 feet Distance at which patient can identify the letters/distance at which a person with "normal" vision can identify the letters
After extra striate cortex, object information processing is split into what two pathways?
What pathway Where pathway
Hyperopia
When light entering the eye is focused behind the retina; farsightedness
Translation perception
When people are passively translated in the dark, they are able to use a joystick to reproduce the distance they traveled quite accurately Interestingly, they also reproduce the velocity of the passive-motion trajectory The otolith organs register acceleration, and our brains mathematically integrate the acceleration and turn it into the perception of linear velocity
Grouping by onset
When sounds begin at the same time, or nearly the same time, they appear to be coming from the same sound source This helps group different harmonics into a single complex tone Consistent with Gestalt law of common fate
pupil dilation
When the pupils in the eyes expand to look large adjusting light intake
Cross-adaptation
When the taste of one food affects the taste of another Example: A sour beverage taste too sour after eating something sweet
When do people react faster
When there is a valid cue compared to an invalid cue
Can each striate cortex cell can respond to more than one eye?
Yes, it can respond to input from both eyes (with preference for one eye's input: ocular dominance)
Human embryos may have what
a VNO that may disappear shortly after birth
Typical light sources emit
a broad spectrum of wavelengths 400-700nm
off center ganglion cell
a cell that increases firing in response to a decrease in light intensity in its receptive field center
somatosensation
a collective term for sensory signals from the body (also includes vestibular system)
RGB space
a cube, with white and black as diagonally opposite corners
Pictorial depth cue
a cue to distance or depth used by artists to depict three-dimensional depth in two dimensional pictures
linear perspective
a depth cue based on the fact that lines that are parallel in the three-dimensional world will appear to converge in a two dimensional image
degrees of visual angle
a function of both objects actual size and distance from the observer
Pointilism
a genre of painting characterized by the application of paint in dots and small strokes Additive color mixtures are achieved by placing dots of different colors in close proximity to each other, rather than subtractive mixtures that are obtained when pigments are mixed together in the same location
attention
a large set of selective processes in the brain that can pick one out of many stimuli make us more (or less) sensitive to stimulation Select "slices" of time or space resolve perceptual ambiguity exist in every modality
sound waves
a longitudinal wave consisting of compressions and rarefactions, which travels through a medium
lateral geniculate nucleus
a place in the thalamus that receives impulses from the optic nerve
Orbitofrontal cortex
a region of the brain in which impulses involving excretion, sexuality, violence, and other primitive activities normally arise
Preferential-looking paradigm
a research technique to explore early infant sensory capacities and cognition, drawing on the principle that we are attracted to novelty and prefer to look at new things Infants prefer to look at more complex stimuli
iris
a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening
Anechoic chamber
a room designed to completely absorb reflections of sound waves
spatial orientation
a sense comprised of three interacting sensory modalities angular motion, linear motion, and tilt
Frame of reference
a system of objects that are not moving with respect to one another
tympanic membrane
a thin sheet of skin at end of outer ear canal. It vibrates in response to sound Common myth - puncturing your eardrum will leave you deaf in most cases it will heal itself it is possible to damage it beyond repair
tuning fork
a two-pronged, fork-like instrument that vibrates when struck; used to test hearing, especially bone conduction
Accidental Viewpoint
a viewing position that produces some regularity in the visual image that is not present in the world
stereopsis
a vivid perception of the three-dimensionality of the world that is not available with monocular vision
longitudinal waves
a wave in which the particles of the medium vibrate parallel to the direction of wave motion
Echo localization or echolocation
ability of some animals to detect the presence and location of object by the reflection of a self-produces sound
Bitter
about 25 different bitter receptors in humans quinine: prototypically bitter-tasting substance cannot distinguish between tastes of different bitter compounds many bitter substances are poisonous Ability to "turn off" bitter sensations--beneficial to liking certain vegetables Bitter sensitivity is affected by hormone levels in women, intensifies during pregnancy
what is a good way of finding out with alive humans what the visual system is sensitive to?
adaptation
Dithering makes use of what
additive color mixing, both in print and on displays
food industry
adds sugar to intensify sensation of fruit juice increase in sweetness (a pure taste sensation) increases perceived olfactory sensation of fruit
adjacent areas on skin are connected to what
adjacent areas in brain
Hering's opponent-process theory
after image in opposite colors (RG, YB)
Taste adaptation
all sensory systems show adaption effects constant application of certain stimulus temporarily weakens subsequent perception Example: adaptation to salt in saliva affects our ability to taste salt
intensity
amount of sound energy falling on a unit area
Ossicles have hinged joints that work like levers to what
amplify sounds
Physical qualities of sound waves include
amplitude, intensity, and frequency
cytochrome oxidase blobs
an area of primary visual cortex rich in the enzyme cytochrome oxidase that responds to color
patch clamp
an extraordinarily sensitive voltage clamp method that permits the measurement of ionic currents flowing through individual ion channels
Reflexive eye movement
an eye movement that is automatic and involuntary
vection
an illusory sense of self motion produced when you are not in fact, moving
Aperture
an opening that allows only a partial view of an object
What does an ILD generally correlate with
angle of sound source, but correlation is not quite as great as it is with ITDs
Spatial disorientation
any impairment of spatial orientation (i.e. our sense of linear motion, angular motion, or tilt)
opponent processes
any process which functions as the antagonist of another process
Odorant
any specific aromatic chemical chemical compounds but not every chemical is an odorant In order to be smelled, molecule must be: Volatile (able to float through air), small, hydrophobic (water repellant)
tastant
any stimulus that can be tasted
Nature or nurture for olfactory hedonics?
are hedonic responses to odors innate or learned evidence from infants: odor preferences often very different from adults cross-cultural data support associative learning an evolutionary argument: some animals exhibit an instinctive aversion to smells from predators Learned taste aversion: Avoidance of a novel flavor after it has been paired with gastric illness
Lateral intraparietal cortex
area in posterior parietal cortex involved in planning and executing eye movements
Anamorphic Art
art that stretches an object into a distorted form that can only be recognized by turning the canvas at a different angle.
How far do touch sensations travel
as far as 2 meters to get from skin and muscles of feet to brain Information must pass through spinal cord (first synapse) Axons of various tactile receptors combine into single nerve trunks Several nerve trunks from different areas of body
Where is the ILD the largest
at 90 degrees and -90 degrees
where are sounds more intense
at the ear closer to the sound source
feature search
attend to one feature dimension Flat search slope, parallel search, efficient search target presence or absence does not affect response time no need for binding
Feature-based attention
attention can enhance the processing of a specific feature which can lead to different perceptions
Zoom lens model
attention expands from fixation, grows to fill whole region, shrinks to include just cued location
object-based attention
attention that is directed to a specific object Attention spreads across objects
vestibulo-autonomic responses
autonomic nervous system Motion sickness
Primary Visual Cortex processes
bars
sine gratings
basic stimulus used in linear systems Visual system breaks down images into sine wave gratings with a particular spatial frequency ("Fourier analysis") Edges of objects produce a single stripe in the retinal image
Hyperpolarization
bending away from tallest stereocilia
Depolarization
bending toward tallest stereocilia
Where is a large proportion of processing done in the visual system?
beyond V1
Balint syndrome
bilateral lesion of parietal lobes 1. Reduced spatial localization abilities 2. Reduced movement of the eyes 3. Inability to perceive more than one object at a time (simultagnosia) 4. Inability to bind features correctly into objects
Brain imaging studies
brain processes odors differently depending on whether they come from nose or mouth
combinatorial code
brain uses the pattern of firing rates across fibers to determine frequency about 1400 fibers in each ear to describe each pattern
How does the motor system solve the problem of why an object in motion may appear stationary ?
by sending out two copies of each command to move eyes One copy goes to eye muscles to move the eye another called the efferent copy goes to an area of the visual system called the comparator
tilt
can be sensed when nodding head up and down as if to say "yes"
angular motion
can be sensed when rotating head from side to side as if to say "no"
Familiar size
can provide precise metrical information if your visual system knows the actual size of the object and the visual angle it takes up on the retina
conductive hearing loss
caused by problems with the bones of the middle ear
Cells with receptive fields that have
center-surround organization
Optic flow
changing angular position of points in perspective image that you experience as you move through the world
congential anosmia
children often pretend to be able to smell
Chili peppers
chilli pepper preference depends on social influences liking unique to humans individuals vary, depends on number of papillae Caapsaicin: chemical in chilis that produces burn. desensitizes pain receptors
What three nerves carry taste information
chorda tympani, glossopharyngeal nerve, vagus
Circumvallate papillae
circular structures that form an inverted V on the rear of the tongue (three to five on each side) Mound like structures surrounded by a trench. Much larger than fungiform papillae
Discriminative touch
classic touch sensations of tactile, thermal, pain, and itch experiences
Cataract
clouding of the lens
What does color provide in ambiguous apparent motion matches
color provides a slight bias to perceive horizontal motion, though it easily overridden with attention
white light
combination of all colors
What do you require when hearing complex sound
combinatorial code
Comparator
compensates for image changes caused by eye movement - inhibits rest of visual system interpreting changes as object motion
Binaral rivalry
competition between the two nostrils for odor perception When a different scent is presented to each nostril, we experience one scent at a time, not a combination of the two scents together
Where pathway
concerned more with locations and shapes of objects
What pathway
concerned more with names and functions of objects
Newsome and Pare study
conducted a study on motion perception in monkeys Trained monkeys to respond to correlated dot motion displays The MT area of the monkeys was lesioned result: monkeys needed about ten times as many dots to correctly identify direction of motion
White noise
consists of all audible frequencies in equal amounts; used in masking
utricle
contains about 30,000 hair cells
What does the brain contain regarding maps and subareas
contains several sensory maps of body, different subareas of S1, and secondary areas as well
what was the effect of the lesion in the newsome and Pare study
contralateral
Transduction
conversion of one form of energy into another
Inner hair cells
convey almost all information about sound waves to brain
outer hair cells
convey information from brain (use of efferent fibers) They are involved in elaborate feedback system when stiff can suppress noise when less stiff, can tune to a given frequency
spindles
convey the rate at which the muscle fibers are changing in length
Y junctions indicate
corners facing the observer
vestibulo-ocular reflexes (VORs)
counter-rotating the eyes to counteract head movements and maintain fixation on a target
Vestibulo-ocular reflexes (VORs)
counter-rotating the eyes to counteract head movements and maintain fixation on a target Angular VOR Torsional eye movements
glossopharyngeal nerve
cranial nerve IX for the middle part of the tongue
visual cliff experiment
created by E.J. Gibson, used to determine when infants can perceive depth If babies do not walk across the cliff then they understand depth cues if they do walk across the visual cliff they do not understand depth cues
How is sound created?
created when objects vibrate vibrations of an object cause molecules in the object's surrounding medium to vibrate as well, which causes pressure changes in the medium
Taste buds
creates neural signals conveyed to brain embedded in structures: papillae (bumps on tongue) each taste bud contains taste receptor cells information is sent to brain via cranial nerves
ampulla
cross section of each canal swells substantially near where the canals join the vestibule
Blue+Green
cyan
two tone suppression
decrease in AN fiber firing rate when two tones presented at similar frequencies at same time
Visual Crowding
deleterious effect of clutter on peripheral object detection Stimuli seen in isolation in peripheral vision are hard to discern when other stimuli are nearby Major bottleneck for visual processing When we can't see an object due to crowding, we have to move our eyes to look directly at it with our high acuity foveal receptive fields
James Clerk Maxwell
demonstrated that light consists of two transverse waves oscillating at right angles to each other
Sound waves travel at a particular speed
depends on medium example: speed of sound through air is about 340 meters/second, but speed of sound through water is 1500 meters/second Light travels a million times faster than sound
It takes time for the cue to be processed and for attention to be
deployed
Accommodation and convergence help perception of what?
depth
Familiar size
depth cue based on knowledge of the typical size of objects
Optic array
describes collection of light rays that interact with objects of the world in front of viewer
L cones
detect long wavelengths 565 nm Red Cones
M Cones
detect medium wavelengths 535 nm Green Cones
parvocellular cells
detect shape - have very high colour spatial resolution
S cones
detect short wavelengths 420nm Blue cones
Contrast
difference in illumination between a figure and its background
Olfactory receptor cells
different from all other sensory receptor cells: Not mediated by protective barrier, make direct contact with the brain Visual receptors protected by cornea, hearing receptors protected by eardrum, taste buds buried in papillae Many drugs can be inhaled OSN axons are thin and slow It takes longer to perceive odors compared to other sense, around 400 ms, compared to 45 ms for visual stimulus to reach the brain
Metamers
different mixtures of wavelengths that look identical More generally, any pair of stimuli that are perceived as identical in spite of physical differences
Temporal code
different parts of the cochlea respond to different frequencies, in which information about the particular frequency of an incoming sound wave is coded by the timing of the neural firing as it relates to the period of soudn -firing every 0.01 seconds (phase) => frequency of sound is 1/0.01 = 100 Hz But limited to soudns <1000Hz (AN fibers can only fire so frequently)
Scotopic
dim light levels at or below the level of bright moonlight rods are sensitive to scotopic light levels All rods contain same photopigment: rhodopsin All rods have same sensitivity to wavelength, making it impossible to discriminate light
Peripheral (exogenous) cue
directly indicates target location
Ernst Weber
discovered that the smallest change in a stimulus that can be detected is a constant proportion of the stimulus level known as Weber's Law
tricky problem (motion)
discriminating motion across the retina that is due to eye movements vs object movements Our visual perception is generally stable in spite of constantly moving eyes... how?
What do relative amounts of direct versus reverberant energy also help us evaluate?
distance
eccentricity
distance from the fixation
Deleting midsections but not vertices does what?
does not hurt identification
Ambiguous display
dots can appear to move vertically or horizontally
Contrast sensitivity varies
dramatically among different species
Gustav Fechner
early German psychologist credited with founding psychophysics and often coined the founder of experimental psychology
Some complex features like depth cues can lead to what
efficient, pop-out searches others require attention to bind together multiple features
magnocellular layer
either of the bottom two neuron-containing layers of the lateral geniculate nucleus, the cells of which are physically larger than those in the top four layers Contains the Parasol system and is adapted for fast, large moving objects
Visual evoked potentials
electrical signals from the brain that are evoked by visual stimuli
Touch receptors
embedded in outer layer (epidermis) and underlying layer (Dermis)
Secondary pain effect
emotional response associated with long term suffering (e.g. cancer patients undergoing chemotherapy)
refracted
energy that is altered as it passes into another medium (e.g. light entering water from the air)
transmitted
energy that is passed on through a surface (when it is neither reflected nor absorbed by the surface)
absorbed
energy that is taken up and not transmitted at all
selective adaptation
evidence that human visual system contains neurons selective for spatial frequency
sweet
evoked by sugars many different sugars that taste sweet glucose: principle source of energy for most animals fructose: even sweeter than glucose sucrose: common table sugar. Combination of glucose and fructose Single receptor responsible for all sweet perception different sweeteners stimulate different parts of the receptor artificial sweeteners stimulate this receptor
Odors appear to be the most potent stimulus for what
evoking memories of previous encounters with the odor other modalities such as vision and taste can also elicit memory memories triggered by odor cues are distinctive in their emotionality Emotion and evocativeness of odor-elicited memories lead to false impression that such memories are especially accurate
analyses
example from auditory mixtures. High note and low note can be played together but we can detect each individual note
Continuity constraint
except at the edges of objects, neighboring points in the world lie at similar distances from the viewer
action for perception
exploratory procedure: stereotyped hand movement pattern used to contact objects in order to perceive their properties Optimal for obtaining precise details about one or two specific properties
Saccades
eyes move at up to 1000 degrees/ second we make about 3 to 4 saccades per second That's 172,800 saccades every day Saccades go to places of "interest"
Change blindness
failure to notice change between two scenes; perception depends on meaning of change
Things really close will move what?
fast
A delta fibers
fast transmission to brain, respond to strong pressure (crushing) and heat initial and quick sharp burst of pain at injury time
Dorsal column medial lemniscal
faster tactile and proprioceptive information, fewer synapses = fast transmission
Wilhelm Wundt
father of experimental psychology, first person to call himself a "psychologist", Founded the first formal laboratory for Psychology in Leipzig, Germany
A symmetrical region tends to be seen as
figure
primary function of nose
filters, warms, humidifies air we breathe Contains small ridges, olfactory cleft, and olfactory epithelium
Olfactory nerves
first pair of cranial nerves. Axons of OSNs bundle together after passing through cribriform plate to form the olfactory nerve
inner ear consists of
fluid filled chamber. it takes more energy to move liquid than air
Foliate papillae
folds of tissue containing taste buds. Located on the rear of the tongue lateral to the circumvallate papillae, where the tongue attaches to the mouth
Why is their color vision in animals
for food and sex foraging for colored food is easier advertisements for bees to trade food for sex (pollination) colorful patterns on tropical fish and toucans provide sexual signals (better health, genes)
frequency
for sound, the number of times per second that a pattern of pressure repeats
chorda tympani
for the most anterior part of the tongue (branch of the facial nerve, cranial nerve VII)
doctrine of specific nerve energies
formulated by Johannes Muller, stating that the nature of a sensation depends on which sensory fibers are stimulated, not on how fibers are stimulated
How many colors did Hering use
four basic colors
cones are concentrated in the
fovea
Rods are concentrated in the
fovea centrails
Drift, tremor, and microsaccades keep the image
fresh
Tectorial membrane
gelatinous structure attached on one end, extends into the middle canal, floats above inner hair cells and touches outer hair cells vibrations cause displacement of the tectorial membrane, which bends stereocilia attached to hair cells and causes the release of neurotransmitters
geons
geometric ions
efferent copy
goes to an area of visual system called the comparator
Are subjects good or bad ant indicating how much they are tilted
good
ganglion cells respond differently to what?
gratings of different spatial frequencies
In order for a mixture of a red light and a green light to look perfectly yellow, you have to add just the right amount of red and just the right amount of what
green
synchrony
group elements changing at the same time
Preattentive features can do what?
guide attention to likely places where the target can be More efficient search lens processing of sensory information
What do hair cells in the vestibular system do
hair cells increasing firing to rotation in one direction and decrease firing to rotation int he opposite direction
What are material properties of objects most important for?
haptic recognition
timbre
harmonic structure of sounds sounds with the same intensity and fundamental frequency can still be perceived as different, this is related to differences in timbre
Cone photoreceptors
have a shorter, tapering outer segment with fewer membranous disks
Torsional eye movements
head is rolled about the x axis, the eyeballs can be rotated a few degrees in the opposite direction to compensate
Angular VOR
head is rotated, eyes maintain fixation
Amplification provided by the ossicles is essential to our ability to what?
hear faint sounds
What is an older sense
hearing
What frequency does an ILD work best for
high frequencies
Contrast sensitivty is reduced with aging, primarily for
high spatial frequencies
Blue (rate intensity function)
high spontaneous firing rate, sensitive to low intensities, saturate quickly compare to rods
S1
homunculus
horizontal pathway
horizontal and amacrine cells interact via lateral inhibition
utricular macula
horizontal plane Sensitive to horizontal linear acceleration and gravity
combinatorial neural code
how can we detect so many different scents if our genes only code for about 1000 olfactory receptors we can detect the pattern of activity across various receptor types intensity of odorant also changes which receptors will be activated specific time order of activation of OR receptors is important
Categorization
how me make sense of the world (how sensation is turned into meaning)
Dualism
idea that the mind has an existence separate from the material world of the body
Motion aftereffect (MAE)
illusion of motion of a stationary object that occurs after prolonged exposure to a moving object Existence of this effect implies an opponent-process system, like that of color vision
Body image
impression of our body in space it is possible to induce an out-of body experience
Does everyone see colors the same way
in general yes but as one ages the lens turns yellow However about 8% of the male population and 0.5% of the female population has some form of color vision deficiency aka color blindness
Umami
in most animals: triggered by many amino acids in humans: only monosodium glutamate (MSG) MSG is a neurotransmitter Pleasant "brothy" or "meaty" taste Added to some East-Asian foods Natural occurence: meat, fish, mushrooms, cheese, some vegetables, especially tomatoes Initial concerns about safety have been disproven
Pleasures of taste
in our evolutionary past, specific hungers for sugar and salt were adaptive Nowadays, these hungers lead many to unhealthy eating habits
Cultural relativism with respect to color perception
in sensation and perception, the idea that basic perceptual experiences may be determined in part by the cultural environment In general, some cultures have words (e.g. another word for varying shades of blue) for more specific colors and thus can easily identify the differences between specific colors more quickly
principle of good continuation
in spite of interruptions, one can still "hear" sound. The missing part is filled-in by the auditory system
Hair cell responses
in the absence of stimulation, hair cells release neurotransmitter at a constant rate When hair cell bundles bend, change in hair cell voltage is proportional to the amount of deflection
Critical period
in the study of development, a period of time when the organisms is particularly susceptible to developmental change
Prosopagnosia
inability to recognize faces
General agnosia
inability to recognize objects
Place agnosia
inability to recognize places
mirror agnosia
inability to understand mirrors
Focus of expansion (FOE)
indicates the heading direct i.e. the direction of subjective motion
Supertaster
individual who is a taster of PTC/PROP and has a high density of fungiform papillae
scene-based guidance
information in our understanding of scenes that helps us find specific objects in scenes
Herman Snellen
invented method for designating visual acuity in 1862
Limbic system
involved in many aspects of emotion and memory includes hippocampus, amygdala, anterior thalamic nucleus, septum, limbic cortex and fornix Olfaction is unique among the senses for its direct and intimate connection to the limbic system
How can hearing loss occur
it can be impaired by: obstructing the ear canal excessive buildup of ear wax in ear canal Conductive hearing loss ostosclerosis
why is refraction necessary?
it is necessary to focus light rays
What does shape provide in ambiguous apparent motion matches
it provides a slight bias to perceive horizontal motion, though it is easily overridden with attention
Additive color mixture
kind of mixing you get if you overlap spotlights in a dark room red, green, blue
Where system of touch
knowing where objects are in the environment when only using touch perception example: finding snooze button on alarm clock in the morning frame of reference: the coordinate system used to define locations in space Egocenter: the center of a reference frame used to represent locations relative to the body
Haptic perception
knowledge of the world that is derived from sensory receptors in skin, muscles, tendons, and joints, usually involving active exploration
Entry-level category/Basic
label that comes to mind most quickly when we identify the object (typically the basic level)
Low spatial frequency represents
large objects
Coding of amplitude and frequency in cochlea
larger amplitude = bigger shear of tectorial membrane
ganglion cells
last stage before information leaves through the eye and travels to and through the brain
The LGN processes right space on the
left side
20/200 (6/60)
legally blind
accomodation
lens can change its shape, and thus alter the refractive power
Accomodation
lens changes its focus
Where are global motion detectors in the brain
lesions in magnocellular layers of LGN impair perception of large, rapidly moving objects Middle temporal lobe (MT) plays an important role in motion perception. The vast majority of neurons in MT are selective for motion in a particular direction
visual pigments
light absorbing molecules created and used by photoreceptors
chromophore
light-catching part of pigment
Which wavelength diffracts more?
long
What can newborns detect?
looming motion
Cataracts
loss of transparency in lens (solved with silicone implants)
What frequency does an ITD work best for?
low frequencies
What type of frequency is diffracted?
low frequencies
Red (rate intensity function)
low spontaneous firing rate, sensitive to high intensities, selective over wide range, compare to cones
Inferotemporal (IT) cortex
lower portion of the temporal lobe, part of the "what" pathway
Harmonics
lowest frequency of harmonic spectrum (fundamental frequency) Auditory system is acutely sensitive to natural relationships between harmonics
What does each otolith organ contain
macula --> a specialized detector of linear acceleration and gravity
Ossicles
malleus, incus, stapes; smallest bones in body
Lateral geniculate nucleus has cells that are what
maximally stimulated by spots of light
A small disparity when talking about the horopter
means that the object is closer to the horopter
A big disparity when talking about the horopter
means that the object is further away from the horopter
How is efficiency measured
measured in terms of search slope, or ms/item tHe larger the search slope (more ms/item), the less efficient the search Some searches are efficient and have small slopes Some searches are inefficient and have small slopes Some searches are inefficient and have large slopes
tactile
mechanical displacement of skin
Otolith organs
mechanical structures in the vestibular system that sense both linear acceleration and gravity
retinal ganglion cells are still doing what
migrating and growing connections with the fovea
Contrast Threshold
minimum contrast (i.e., difference between light and dark bars) to detect pattern at specific spatial frequency (1000-990)/1000 = 0.01
two-point threshold
minimum distance necessary between two points of stimulation on the skin such that the points will be felt as two distinct stimuli
strabismus
misalignment of eyes such that single object in space is imaged on fovea of one eye and non-foveal area of the other (turned) eye
what does sensory integration typically lead to
more accurate information than can be obtained from individual senses alone
Superordinate-level category
more general term
When there is more fluid there is
more refraction
Otosclerosis
more serious type of conductive loss. Caused by abnormal growth of middle ear bones; can be remedied by surgery
motion-induced blindness
motion can make salient objects disappear
Linear motion
movements represented in terms of translation in the x-, y-, and z axes
Olfactory cleft
narrow space at back of nose into which air flows, where the main olfactory epithelium is located
myopia
nearsightedness: When the light entering the eye is focused in front of the retina and distant objects cannot be seen sharply; light converges in front of the retina
Phase locking
neuron fires only at distinct point in the period (cycle) of sound wave at given frequency
Moving from V1 to IT in the what pathway,
neurons respond to more and more complex stimuli
Is the tongue map true?
no
are geons always the best descriptions of objects?
no
emmetropia
no refractive error; normal vision
Geons are recognized by their what?
nonaccidental properties (helps solve problem of invariance)
Human olfactory apparatus
nose
inattentional blindness
not perceiving things that are in plain sight. Caused by absence of attention to the unseen object
Liking for saltiness is
not static early experiences can modify salt preference chloride-deficiency in childhood leads to increased preference for salty foods later Gestational experiences may affect liking for saltiness
Support
object does not appear to be resting on a surface
Gestalt law of common fate
objects moving in the same direction or moving in synchrony are perceived as a group or unit
Identification is difficult if geons are what?
obscured (vertices deleted)
What is optical flow used extensively in computer vision for?
obstacle detection and avoidance lane following automatic landing systems flight stabilization motion detection (e.g. alarm systems)
Parallax barrier
occluders positioned to selectively block pixels for one or the other eye
T junctions indicate
occlusion
orthonasal olfaction
olfaction through the nostrils
What is the retina of the nose?
olfactory epithelium
odors
olfactory sensations
common fate
onset and offset at the same time with a very short delay, e.g. in harmonics
Lenticular arrays
optics redirects light selectively into a particular eye
Neuroanatomical and evolutionary connections between odor and emotion
orbitofrontal cortex olfaction is processed here also the cortical area for assigning affective value (i.e., hedonic judgement) Helps explain increased emotionality of smells
Cognitive aspects of pain
pain: generally subjective experience, two components: sensation of painful source, emotion that accompanies it Areas S1 and S2 are responsible for sensory aspects of pain Researchers have recently identified areas of brain that correspond to more cognitive aspects of painful experiences
Attack (sound)
part of a sound during which amplitude increases
autonomic nervous system
part of the nervous system innervating glands, heart, digestive system, etc., and responsible for regulation of many involuntary acitons blood pressure is regulated by vestibulo-autonomic responses
triangle test
participant given three odors to smell, two of which are the same and one that is different participant must identify the odd odor the order of the three odors is varied and tested several times to increase accuracy difference between same and odd odors varied to determine discrimination threshold
Magnitude estimation
participants report how much (e.g. how many degrees) they think they tilted, rotated, or translated
Biological motion
pattern of movement of living things (i.e., humans, animals)
loudness
perceived intensity or magnitude
Phantom limb
perceived sensation from a physically amputated limb of the body parts of brain listening to missing limbs not fully aware of altered connections, attribute activity in these areas to stimulation from missing limb real pain might be felt if they perceive their phantom limbs to be in uncomfortable positions
proprioception
perception mediated by kinesthetic and vestibular receptors
pitch
perception of different frequencies
Timber aftereffect known as timbre contrast or timbre after effect
perception of timbre depends on context in which sound is heard
Gestalt perception assumes what?
perception relies on laws of physics, assumes viewpoints are not accidental
Are axes defined relative to person or gravity
person
Each macula is roughly what
planar and sensitive primarily to shear forces Hair cells are encased in a gelatinous structure that contains calcium carbonate crystals called otoconia
Basilar membrane
plate of fibers that forms the base of the cochlear partition and separates the middle and tympanic canals in the cochlea Any remaining pressure from intense sounds: transmitted from helicotrema back through tympanic canal, where absorbed by round window
inhibition
plays an important role in processing taste information in the brain functions to protect our whole mouth perception of taste when there are injuries to taste system. descending inhibition from taste cortex blocks pain perception has survival value: we need to eat even if we have a mouth injury
x axis (vestibular system)
points forward, direction the person is facing
y-axis (vestibular system)
points laterally, out of the person's left ear
corresponding retinal points
points on the retina of each eye where monocular retinal images of a single object appear are same distance from the fovea in each eye
z-axis
points vertically out of the top of the head
What do the red arrows in the aperture problem show?
possible velocity vectors that would all produce the same pattern of motion within the aperture
Do we learn to like or dislike smells separately for retronasal versus orthonasal olfaction?
possibly however, if an aversion is acquired retronasally, it usually shows up orthonasally as well
basal cells
precursor cells to olfactory sensory neurons
What are some features of the PPA
prefers scenes over faces or objects contains a neural representation of categories of natural scenes Category representation robust to the way the scenes are presented, e.g. line drawings vs. color photographs
insular cortex
primary cortical processing area for taste, first receives taste information
Selective
processing restricted to a subset of possible stimuli
supporting cells
provide metabolic and physical support for the olfactory sensory neurons
Receptors in tendons
provide signals about tension in muscles attached to tendons
scene context
provides an important cue for object detection
What does proximity provide in the ambiguous apparent motion matches
proximity provides a bias to perceive horizontal motion its also provides a bias to perceive vertical motion
How can the filtering property of the auditory system be measure
psychophysically This is achieved by measuring the ability of listeners to detect tones in the presence of bandpass noise
what are the two mechanisms for dark and light variation?
pupils regulates the amount of light entering the eye ganglion cells ignore variation in overall light level
Contrast sensitivity at birth is what?
quite poor but improves gradually with development
How do sound waves propagate in open air?
radially
critical bandwidth
range of frequencies that are conveyed within channel in auditory system
akinetopsia
rare neurophysiological disorder in which the affective individual has no perception of motion caused by disruptions to cortical area MT
Receptors in joints
react when joint is bent to an extreme angle
20/10 (6/3)
really good eye vision
Midget bipolar cells
receive input from a single cone
diffuse bipolar cell
receive input from multiple rods (up to fifty)
Faster reaction times for object-based attention when red dot is valid or near cued in the same area
red indicator flashes prior
What colors are complementary
red produces green (and vice versa) Yellow produces blue (and vice-versa)
Saccadic suppression
reduction of visual sensitivity that occurs when one makes a saccadic eye movement; eliminates smear from retinal image motion during an eye movement
Ipsilateral
referring to the same side of the body/brain
Most of the light we see is
reflected
Cone of confusion
regions of positions in space where all sounds produce the same time and level (intensity) differences (ITDs and ILDs)
What do the vestibular organs respond to?
respond to changes in velocity or acceleration
Stripe Detector
responds best to a line of light that has a particular width, surrounded on both sides by darkness
Anterior Cingulate cortex
responds differentially to hypnotic suggestions of pain
Midget bipolar cell off
responds to decreases in light
Midget bipolar cell on
responds to increases in light
What does stimulating taste receptor cells result in?
responses in taste nerves
4 kinds of pigment
rhodopsin (rods), long, medium, short (cones)
The LGN processes left space on the
right side
what are the three directions for the sense of rotation
roll, pitch, yaw
roll
rotation around x-axis
Pitch
rotation around y-axis
yaw
rotation around z-axis
interest when referring to saccades
scene based or knowledge based (bottom-up or top-down attention)
Adenosine triphosphate (ATP; a neurotransmitter)
secreted by cells without synapses
Olfactory epithelium
secretory mucosa functions to detect odorants in the inspired air
subtle differences between sensation and perception
sensation occurs when scent is neurally registered Perception occurs when becoming aware of scent sensations
two components of pain
sensation of painful source, emotion that accompanies it
olfaction
sense of smell
Adaptation
sense of smell is essentially a change detector examples: walking into a bakery and can only smell fresh bread for a few minutes. Someone who wears perfume every day cannot smell it might put a lot on
Gustation
sense of taste
linear motion
sensed when accelerating or decelerating in a car
Benefit of pain perception
sensing dangerous objects (hot pots in the kitchen) case of "Miss C" Born with insensitivity to pain Could not protect herself (did not sneeze or cough) Died at age 29 from untreated injection This is a huge problem for diabetic patients, who often lose sensation of their feet and become invalids because of untreated minor injuries
skin
sensory organ for touch largest sensory organ About 1.8 square meters (19 square feet) About 4 kg (9 pounds)
Mechanoreceptors
sensory receptors that are responsive to mechanical stimulation (pressure, vibration, movement) Head motion causes hair cell stereocilia to deflect, causing a change in hair cell voltage and altering neurotransmitter release
What does a prism do?
separates visible light into several colors
d prime
serves as a measure of signal separability (sensitivity of measurement). It tells us by how many standard deviations the two signals are separated. Defined as d' = Z(hit rate) - Z(false alarm rate) Z stands for the cumulative Gaussian distribution
Light from an object is composed of about how many wavelengths
several
spinothalamic pathway
several synapses in spinal cord slower information transmission provides mechanisms for pain inhibition
pheromones
signals for chemical communication between members of the same species that do not need to have any smell
What are VORs accomplished by
six oculomotor muscles that rotate the eyeball
Texture cue can give rise to an illusion in what?
size
Microvilli
slender projections on the tips of some taste buds that extend into the taste pore contain the sites that bind to taste substances not tiny hairs (as the name implies): we now know they are extensions of the cell membrane
C fibers
slower response sustained stimulation throbbing sensation that evolves after initial surge of pain
spinothalamic
slower, evolutionary older heat and pain, multiple synapses
Things really far will move what?
slowly
Two central categories about tastants
small charged particles that taste salty or sour (small ion channels in microvilli membranes allow some charged particles to enter but not others) Molecules perceived by G protein-coupled receptors (GPCRs) similar to those in the olfactory system. These molecules taste sweet or bitter
A high spatial frequency represents:
small objects
Filiform papillae
small structures on the tongue that provide most of the bumpy appearance. Have no taste function
ciliary muscle
smooth muscle portion of the ciliary body, which contracts to assist in near vision Assists in eye focus
Where are the neurons that are sensitive to tickling located
somatosensory cortex
How are touch sensations represented in the brain?
somatotopically analogous to retinotopy found in vision
All sounds can be described as
some combination of sine waves
relative size and relative height both provide what
some metrical information
stapes transmits vibrations of
sound waves to oval window, another membrane which represents border between middle and inner ear
Outer ear
sounds are first collected from environment by the pinnae sound waves are funnelled by the pinna into ear canal length and shape fo ear canal enhance sound frequencies main purpose of canal is to protect the tympanic membrane (eardrum)
What are some strategies to segregate sound sources
spatial separation, separation on basis of sounds' spectral or temporal qualities Auditory stream segregation: Perceptual organization of a complex acoustic signal into separate auditory events for which each stream is heard as a separate event
Retinal ganglion cells and LGN process
spots
What is the ability to perceive salt like?
static low sodium diets will increase intensity of salty foods over time
Evoked OAE
stimulated by pure tone frequency computed as difference between stimulation and sound measured at the ear used as a non-invasive hearing test
The reaction time depends on what
stimulus onset asynchrony between cue and stimulus
estropia
strabismus in which on eye deviates inward
boundary between the ambient air and the cornea does what?
strongest refraction
superior colliculus
structure in midbrain that plays important role in initiating and guiding eye movements when the superior colliculus is stimulated with electrical signals, eye movements can be observed
single unit recordings
study firing of individual neurons
Psychoacousticians
study how listeners perceive pitch
Multi unit recordings
study small ensembles of neurons
miss
subject did not respond when a signal was present
Polar angle
subset of visual field
Mixing of pigments is
subtractive color mixing
When a pattern of non-overlapping blue and yellow pigment is blurred the resultant mixture is additive (Gray) as opposed to what
subtractive green
Ménière's disease
sudden experience of dizziness, imbalance, and spatial disorientation can cause sudden falling down, can cause repeated vomiting from severe motion sickness caused by accumulation and sudden release of endolymph in the inner ear Often accompanies by tinnitus (ringing in the ear) Attacks are unpredictable Prognosis: often ends up in "burnt-out" stage, inner ear function lost, including hearing possible treatments: medications, implanted devices, or sometimes removal of the vestibular apparatus itself
ganglion cells can still report activity as they what?
sum up what going on at the photoreceptor level
lateral view of eye muscles
superior oblique superior rectus lateral rectus inferior rectus inferior oblique
what are the six muscles that are attached to each eye
superior oblique superior rectus lateral rectus inferior rectus inferior oblique medial rectus
Top view of eye muscles
superior rectus lateral rectus superior oblique medial rectus
levels of categorization
superordinate, basic, subordinate
Hair cells
support the stereocilia that transduce mechanical movement in the vestibular labyrinth into neural activity sent to the brain stem Hair cells act as the mechanoreceptors in each of the five vestibular organs
Binocular suppression
suppression of one of the two eye images
what taste preferences do infants show?
sweet evokes a "smilelike" expression followed by sucking sour produced pursing and protrusion of lips Bitter produced gaping, movements of spitting, and sometimes vomiting movements
What do type III cells have
synapses
Survival value of taste
system for detecting nutrients and antinutrients bitter: might signal poisons sour: configured to detect acidic solutions that might harm the body sweet and salty: our bodies need sodium and sugar to survive umami: seeking protein-rich food
four components of touch
tactile, temperature, pain, body sensations
The farther an object is rotated away from a learned view the longer it
takes to recognize
ATP can act on what
taste nerve fibers and adjacent cells
Orientation Tuning
tendency of neurons in striate cortex to respond optimally to certain orientations and less to others
What are the two muscles that comprise the middle ear
tensor tympani and stapedius purpose: to tense when sounds are very loud, muffling pressure changes Acoustic reflex takes ~200ms, So cannot protect against abrupt sounds (e.g. gun shot)
Vestibular information reaches the cortex via
thalamo-cortical pathways
ascending vestibular pathways pass from the vestibular nuclei to
thalamus on their way to the temporo-parieto-insular cortex
motion entrainment
the addition of flanker dots causes the center dot to appear in motion behind a square occluder
Perceptual phase space
the appearance of a display can have qualitatively different states depending on the iSI and displacement
Ensemble statistics
the average and distribution of properties, such as orientation or color, over a set of objects or a region in a scene
interposition
the background to pass through the object
chorda tympani
the branch of cranial nerve VII (the facial nerve) that carries taste information from the anterior, mobile tongue (the part of the tongue you can stick out)
Egocenter
the center of a reference frame used to represent locations relative to the body
Saturation
the chromatic strength of a hue
flavor
the combination of true taste (sweet, salty, sour, bitter, umami, and fat)
Flavor
the combination of true taste (sweet, salty, sour, bitter, umami, and fat) and retronasal olfaction
Binocular rivalry
the competition between the two eyes for control of visual perception, which is evident when completely different stimuli are presented to the two eyes
aromatherapy
the contention that odors can influence, improve, and alter mood, performance, and well-being, as well as the physiological correlates of emotion such as heart rate, blood pressure, and sleep No evidence for pharmacological effect of odors in humans effects explained by the emotional memory association with the scent odors can make you feel energized and have downstream effects on physiology and performance (E.g. peppermint smell can make you run faster, IF based on previously acquired association)
where does the eye focus images?
the cornea and the lens
LGN functions as a gateway to what?
the cortex
Relative disparity
the difference in absolute disparities of two elements in the visual scene (Relative depth of objects)
brightness
the distance from black in color space
aperture problem
the fact that when a moving object is viewed through an aperture (or a receptive field), the direction of motion of a local feature or part of the object may be ambiguous
What is an example of vection
the feeling of flying while watching an IMAX movie, being stopped in your car at a light next to a bus. The bus begins to roll forward and you press on the brake because you feel as if you are rolling backwards
perilymph
the fluid that fills ear canals
color opponent theory
the idea that color vision is based on a system of paired opposites of color
Specific hungers theory
the idea that deficiency of a given nutrient produces craving (a specific hunger) for that nutrient cravings for salty or for sweet are associated with deficiencies in those substances However, the theory has not been supported for other nutrients, such as vitamins Theory only holds for sweet and salty foods
tip-of-the-nose phenomenon
the inability to name an odorant, even though it is familiar one has no lexical access to the name of the odorant, such as first letter, rhyme, number of syllables, etc. One example of how language and olfactory perception are deeply disconnected Anthropologists have found that there are fewer words for experiences of smells compared to other sensations
agnosia
the inability to recognize familiar objects.
specific anosmia
the inability to smell one specific compound amid otherwise normal smell perception 50% of population has specific anomsia to androstenone found in armpit sweat and pork 50% perceive as "sweet musky-floral" and 50% perceive it as an unpleasant "urinous" podor sensitivity to androstenone can be trained (but why?) Shape-pattern theory can explain these findings
What happens to the endolymph when the head rotates
the inertia of the endolymph causes it to lag behind, leading to tiny deflections of the hair cells
subtractive color mixture
the kind of mixing you get if you illuminate colored filters with white light from behind cyan, magenta, and yellow
illuminant
the light that illuminates a surface
Odor hedonics
the liking dimension of odor perception, typically measured with scales pertaining to an odorant's perceived pleasantness, familiarity, and intensity
Direction (vestibular system)
the line along which one faces or moves, with reference to the point or region toward which one is facing or moving
amplitude
the magnitude of displacement of a sound pressure wave
Mitral cells
the main projective output neurons in olfactory bulbs
stapes has a smaller surface than
the malleus, so sound energy is concentrated
graded potential
the more photons, the less neurotransmitter
First order motion
the motion of an object that is defined by changes in luminance
Ensemble statistics are computed in what pathway?
the nonselective pathway
spatial frequency
the number of cycles of a grating per unit of visual angle (usually specified in degrees)
size
the object appears too large or too small relative to other objects in the scene
position
the object is likely to occur in that scene but is unlikely to be in that particular position
probability
the object is unlikely to appear in the scene
figure-ground
the organization of the visual field into objects (the figures) that stand out from their surroundings (the ground).
orbitofrontal cortex (OFC)
the part of the frontal lobe of the cortex that lies above the bone (orbit) containing the eyes receives projections from insular cortex involved in processing of temperature, touch, smell, and taste, suggesting it may be an integration area
categorical perception
the perception of speech sounds as belonging to discrete categories
Reverberation
the persistence of sound in a particular space after the original sound is produced due to reflections of the original sound
Mixing wavelengths does not change
the physical wavelengths
Rate Saturation
the point at which a nerve fiber is firing as rapidly as possible and further stimulation is incapable of increasing the firing rate Rate saturation means we cannot use a direct decoding rule
Sensory integration
the process of combining different sensory signals
Figure-ground assignment
the process of determining that some regions of an image belong to a foreground object (figure) and other regions are apart of the background (ground)
Cognitive Habituation
the psychological process by which, after long-term exposure to an odorant, one is no longer able to detect that odorant or has very diminished detection ability
retronasal olfactory sensation
the sensation of an odor that is perceived when chewing and swallowing force an odorant in the mouth up behind the palate into the nose such odor sensations are perceived as originating from the mouth, even though the actual contact of odorant and receptor occurs at the olfactory mucosa
vestibular organs
the set of five organs located in each inner ear that sense head motion and head orientation with respect to gravity three semicircular canals two otolith organs also called the vestibular labyrinth or vestibular system an often overlooked sense: evolutionarily very old
Displacement
the shift of the depicted pattern from frame 1 to frame 2
What is the tip of each stereocilium connected to and what is the thing that connects it called?
the side of its neighbor by a tiny filament called a tip link
amplitude (vestibular)
the size (increase or decrease) of a head movement (e.g. angular velocity, linear acceleration, tilt)
acuity
the smallest spatial detail that can be resolved
what does the cation trigger
the taste receptors via epithelium sodium channels (ENaC) All salts taste at least a little salty, but NaCl is the saltiest
Free fusion
the technique of converging or diverging the eyes in order to view a stereogram without a stereoscope
RSVP is used to study what
the temporal dynamics of visual attention
Color constancy
the tendency of a surface to appear the same color under a fairly wide range of illuminants must discount the illuminant and determine what the true color of a surface is regardless of how it appears
Similarity
the tendency to perceive things that look similar to each other as being part of the same group Group things together that are more similar
color space
the three-dimensional space, established because color perception is based on the outputs of three cone types, that describes the set of all colors
Anisometropia
the two eyes have different refractive errors (e.g. one is hyperopic and the other is not)
Areas of cortex that receive projections from the vestibular system also project where
the vestibular nuclei
Labeled lines coding
theory of taste coding in which each taste fiber carries a particular taste quality (major source of controversy in literature) Other possibilities: patterns of activity across taste neurons temporal coding of taste neurons Examples of types of coding in other senses: color vision and olfaction use patter coding Hearing uses labeled-line approach olfaction uses temporal coding
Pre-attentive features are free floating until what?
they are bound together by spatial attention
How do cones respond?
they are fast, wide range, but only after a minimum of light (10 photons per second)
How do rods respond?
they are sensitive but slow and can respond to one photon
Reissner's membrane
thin sheath of tissue separating the vestibular and middle canals in the cochlea
Knowledge and expectations can influence perception of what
tilt and motion
otoconia
tiny calcium carbonate stones in the ear that provide inertial mass for the otolith organs, enabling them to sense gravity and linear acceleration
what is the goal of color perception
to perceive changes in illumination (color of light) To perceive changes in reflectance (color of object)
Grouping by timbre
tones that have increasing and decreasing frequencies, or tones that deviate from rising/falling pattern "pop out" of sequence
what is a possible solution to lesions?
transcranial magnetic stimulation coil introduces strong magnetic field that is sent to a specific region
Interocular transfer
transfer of an effect (e.g. adaptation) from one eye to the other
light waves
transverse oscillations in electric and magnetic fields
Pain
triggered by nociceptors responses to noxious stimuli can be moderated by anticipation, religious belief, prior experience, watching others respond, excitement
What are some characteristics of reichardt motion detectors?
tuned to particular speeds If a moving object is too slow or too fast, then signals will arrive at the comparators at different times= no signal Tuned to specific directions of motion if an object moves in the wrong direction, then signals will arrive at the comparators at different times = no signal Simple operation, but can lead to problems: may respond to stationary patterns or flicker
place code
tuning of different parts of cochlea to different frequencies (mostly due to shape of basilar membrane)
What is salt made up of
two charged particles cation Na+ Anion Cl-
HSB space
two cones, connected at their base, with white at the top tip and black at the bottom tip
good continuation
two elements will tend to group together if they lie on the same contour
How many stages are involved in stereopsis
two stages
What type of picture is recognized easily but poorly haptically
two-dimensional pictures
Two otolith organs in each ear
utricle and saccule
Health consequences of taste sensation
variations in sensory properties of foods and beverages affects food preferences and diet some vegetables are too bitter for supertasters among men getitng routine colonoscopies, those tasting PROP as the most bitter had the most colon polyps Fats also taste bitter to supertasters, if they avoid it could lower their risk for heart disease
Visual-vestibular integration
vection: an illusory sense of self motion produced when you are not, in fact, moving
saccular macula
vertical plane Sensitive to vertical linear acceleration and gravity
What comprises the three-neuron arc
vestibular afferent neurons (blue) Connecting neurons (green) Efferent oculomotor neurons (red)
RBC predicts what
viewpoint invariance
What are geometric properties of objects most important for?
visual recognition
If adaptation to a stimulus occurs, then it must be that a group of neurons was what?
was coding that stimulus and got fatigued
sine wave (Sound)
waveform for which variation as a function of time is a sine function
diffracted
waves can be bent around obstacles.
To calculate or perceive motion what do we not require?
we do not require discrete objects just as we do not require objects to perceive depth (RDS)
In the electromagnetic spectrum
we perceive light of a wavelength of 700nm as red
Familiarity and intensity
we tend to like odors we've smelled many times before Intensity has a more complicated relationship with odor liking Inverted U shape function Linearly decreasing function
threshold estimation
what is the minimum motion needed to correctly perceive motion direction?
optokinetic nystagmus (OKN)
when following a moving object, the eyes return to the object's original position when the object disappears from the field of view
rotation vection
when observers are looking at a rotating display they report a sense of tilt but of not feel as if they have been turned upside down
Torsional eye movements
when the head is rolled about the x-axis, the eyeballs can be rotated a few degrees in oppsite direction to compensate
Absolute threshold for touch
wing of fly on cheek dropped from 3 inches
Olfactory detection thresholds
women generally have lower thresholds than men especially during ovulatory period of menstrual cycles, but sensitivity not heightened during pregnancy Professional perfumers and wine tasters can distinguish up to 100,000 odors By 85, 50% of population is effectively anosmic
When both M and L cones are activated what color do you perceive?
yellow
Is olfaction mostly synthesis
yes and analytical abilities can be trained
Retina
A light sensitive membrane in the back of the eye that contains rods and cones, which receive an image from the lens and send it to the brain through the optic nerve Decreases amount of light by 50%
Absolute threshold for smell
One drop of perfume diffused throughout a three-room apartment
Synapse
The junction between neurons that permits information transfer
functional magnetic resonance imaging (fMRI)
an imaging technique used to examine changes in the activity of the working human brain by measuring changes in the blood's oxygen levels
neurophysiology
brain areas involved in perception
Absolute threshold for vision
candle flame 30 miles away
just noticeable difference
the minimal change in a stimulus that can just barely be detected
accommodation
the process by which the eye's lens changes shape and thus alters the refractive power
Psychophysics
the science of defining quantitative relationships between physical and psychological (subjective) events (What can we measure and how can we measure it?)
Psychophysics
the science of defining quantitative relationships between physical and psychological events
electrophysiology
the study of the electrical activity of cells
What are the five things one can do with light?
1. Absorbed 2. Diffracted 3. Reflected 4. Transmitted 5. Refracted
What is the order for perception of something?
1. Capturing physical energy 2. Physical Stimulation 3. Transduction into neural signal: sensation 4. Transmission of neural signal to the brain 5. Cortical processing: Perception 6. Active feedback
Signal detection theory
A psychophysical theory that quantifies the response of an observer to the presentation of a signal in the presence of noise
Astigmatism
A visual defect caused by the unequal curving of one or more of the refractive surfaces of the eye, usually the cornea
transverse waves
A wave in which the particles of the medium move perpendicularly to the direction the wave is traveling
light
A wave; a stream of photons, tiny particles that each consist of one quantum of energy
Electroencephalogram (EEG)
An amplified recording of the waves of electrical activity that sweep across the brain's surface. These waves are measured by electrodes placed on the scalp.
Weber's Law
As stimulus level increases or decreases, the magnitude of change must increase proportionately to remain noticeable
Hermann von Helmholtz
First person to measure the speed of neural impulses, invented the ophthalmoscope, Wrote on the sensation of tone, one of the first studies of auditory perception
Santiago Ramon y Cajal
Hispanic doctor awarded the Nobel Prize in 1906 for his work on the structure of the nervous system
James J. Gibson
Instead of viewing perception as passive, he postulated an active "information pick-up" of perceptual units from environment. Gibson coined the term "affordance" to describe the opportunities for action provided by a particular object or environment - very influential in design and ergonomics
Rods
Photoreceptors that are specialized for night vision
Materialism
The idea that only thing that exists is matter, and that all things, including mind and consciousness, are the results of interactions between bits of matter
Panpsychism
The idea that the mind exists as a property of all matter--that is, that all matter has consciousness
Tapetum
The iridescent portion of the choroid tissue that is located behind the retina. Found in animals that have good night vision, it reflects light back through the retina.
Crystalline lens
The lens inside the eye, which enables changing focus.
Perception
The processing and interpretation of neural energy from sensations
Plato and "The Allegory of the Cave"
Used by Plato to describe moving across the Divided Line (realm of becoming to the realm of being) and the Simile of the Sun. People are chained like prisoners forced to stare at the wall of a cave. What they perceive to be real are actually artificial reflections cast by fire and puppets. The philosopher is the prisoner who broke free to ascend outside the cave into the sunlight.
6 senses
Vision Audition Smell (olfaction) Taste (gustation) Touch Balance
Positron Emission Tomography (PET)
a method of brain imaging that assesses metabolic activity by using a radioactive substance injected into the bloodstream
Magnetoencephalography (MEG)
technique that measures brain activity by detecting tiny magnetic fields generated by the brain
When we want to identify perceptual processes, we can measure
the behavioral response of organisms to stimulation and the specific neural energies in response to stimulation
sensitivity
the ease with which an observer can tell the difference between two stimuli (or the presence and absence of a stimulus)
correct rejection
the subject did not respond when no signal was present
false alarm
the subject perceived a signal when none was present
hit
the subject responded affirmative when a signal was present
Absolute threshold for hearing
the tick of a watch 20 feet away in a quiet room