Psych 101, Week 8

Selective attention

"Everyone knows what attention is.. it is the taking possession by the mind, in clear and vivid form, of one out of what seems several simultaneously possible objects or trains of thought.. it implies withdrawal from some things in order to deal effectively with others.." -Selective attention is the cognitive faculty that allows us to filter out irrelevant sensory information in favour of the relevant (to increase the signal:noise ratio)

Ian Waterman

-"At the tender age of only 19, Ian Waterman became sick with a viral diarrhea which slowly begun to diminish his co-ordination. The virus that caused him to lose all sense of touch and proprioception from the neck down. He could initiate a movement but did not have any control over it or where it happened. He could be lying on the bed and yet not feel his body at all. And if he did not look at them, he could not tell where his arms or legs or any other part of his body were at any given time. Through constant concentration and visual input, Ian Waterman slowly learned to move again. He was able to do so by planning and concentrating on every movement his body had made to make in order to produce the desired action." -Through very elaborate and time-consuming efforts, he was able to learn how to walk again by focusing on his visual imagery of where his body parts should be and also through his visual feedback of where his body parts currently were.

Tonotopic organization of the cochlea

-Hair cells closest to the oval window are maximally responsive to high frequency sounds -Organized by frequency of various stimuli -Hair cells closest to the end of the cochlea - apex of the cochlea - are maximally responsive to low frequency sounds -Travelling down length of cochlea, some hair cells are responsive to intermediate frequencies of sound

Activation of hair cells

-A mechanical process -Stimulation of the hair cell ultimately leads to activation of the cell -Hair cells become activated, and they generate neural impulses that travel along the auditory nerve to the brain -Auditory information is shuttled to the inferior colliculus, the medical geniculate nucleus of the thalamus, and then to the auditory cortex in the temporal lobe of the brain for processing - Like the visual system, there is also evidence suggesting that information about auditory recognition and localization is processed in parallel streams

Touch-related stimuli receptors

-A number of receptors are distributed throughout the skin to respond to various touch-related stimuli. -These receptors include Meissner's corpuscles, Pacinian corpuscles, Merkel's disks, and Ruffini corpuscles. -Meissner's corpuscles respond to pressure and lower frequency vibrations, and Pacinian corpuscles detect transient pressure and higher frequency vibrations. Merkel's disks respond to light pressure, while Ruffini corpuscles detect stretch -In addition to the receptors located in the skin, there are also a number of free nerve endings that serve sensory functions. -These nerve endings respond to a variety of different types of touch-related stimuli and serve as sensory receptors for both thermoception (temperature perception) and nociception (a signal indicating potential harm and maybe pain). -Sensory information collected from the receptors and free nerve endings travels up the spinal cord and is transmitted to regions of the medulla, thalamus, and ultimately to somatosensory cortex, which is located in the post-central gyrus of the parietal lobe.

Pattern perception

-According to Gestalt theorists, pattern perception, or our ability to discriminate among different figures and shapes, occurs by following the principles described above. -You probably feel fairly certain that your perception accurately matches the real world, but this is not always the case. -Our perceptions are based on perceptual hypotheses: educated guesses that we make while interpreting sensory information. -These hypotheses are informed by a number of factors, including our personalities, experiences, and expectations. We use these hypotheses to generate our perceptual set. For instance, research has demonstrated that those who are given verbal priming produce a biased interpretation of complex ambiguous figures

Proximity

-Another Gestalt principle for organizing sensory stimuli into meaningful perception is proximity. This principle asserts that things that are close to one another tend to be grouped together -How we read something provides another illustration of the proximity concept. For example, we read this sentence like this, notl iket hiso rt hat. We group the letters of a given word together because there are no spaces between the letters, and we perceive words because there are spaces between each word. Here are some more examples: Cany oum akes enseo ft hiss entence? What doth es e wor dsmea n?

Thermoreceptors

-Another receptor in our skin addition to mechanoreceptors -Thermoreceptors: Responds to changes in skin temperature -2 distinct populations = warmth fibers and cold fibers -Onet set will respond to increase in firing when exposed to warm temperatures and other set will respond to an increase in firing when there is exposure to cold temperatures

Nocireceptors

-Another receptor on skin -Responds to painful stimuli -Sensory receptors that transmit information about noxious stimulation that causes damage or potential damage to the skin

Gustatory system

-Approximately 34 receptor protein: 1 umami/savoury, 2 sweet, 30 bitter, 1(?) salty receptor proteins (note: no sour receptor proteins identified as yet) -Sourness seems to be mediated by the acidity of the substance consumed, and that acidity has effects on the taste receptors -4 basic groupings of tase = sweet, salty, sour bitter -5th = umami, yummy, associated with a taste for monosodium glutamate -6th = fatty content of a given food

Mechanoreceptors

-Are to the skin as the touch homunculus is to the parietal lobe

Olfactory system

-Around 300 receptor proteins: chemical stimuli bind to receptor proteins in dendrites of olfactory receptors

Selective attention is an essential mental mechanism as it allows us to

-Attend to particular elements of our environment at the expense of other elements.

Binaural cues

-Binaural cues provide information on the location of a sound along a horizontal axis by relying on differences in patterns of vibration of the eardrum between our two ears. -If a sound comes from an off-center location, it creates two types of binaural cues: interaural level differences and interaural timing differences. -Interaural level difference refers to the fact that a sound coming from the right side of your body is more intense at your right ear than at your left ear because of the attenuation of the sound wave as it passes through your head. -Interaural timing difference refers to the small difference in the time at which a given sound wave arrives at each ear. -Certain brain areas monitor these differences to construct where along a horizontal axis a sound originates

Exogenous attention

-Bottom up processes -e.g: loud noise (auditory signal directs attention to auditory stimulus) -Mediated by sensory receptors, external stimuli (sensory) -This type of attention is used when we are reactive to features of the environment as opposed to our internal goal

Bias, Prejudice, and Cultural factors - perception

-Built from sensations, but influenced by our own experiences, biases, prejudices, and cultures, perceptions can be very different from person to person. -Research suggests that implicit racial prejudice and stereotypes affect perception. -For instance, several studies have demonstrated that non-Black participants identify weapons faster and are more likely to identify non-weapons as weapons when the image of the weapon is paired with the image of a Black person. -Furthermore, White individuals' decisions to shoot an armed target in a video game is made more quickly when the target is Black. -This research is important, considering the number of very high-profile cases in the last few decades in which young Blacks were killed by people who claimed to believe that the unarmed individuals were armed and/or represented some threat to their personal safety.

Dendrites of receptor cells for the olfactory system

-Has receptors that bind particular odourant molecules -Binding of the odourant molecules constitutes the conversion or transduction of the odourant molecules into a neural signal

Loss of kinesthetic receptors

-Ian Waterman lost his ability to know where his body parts are in space, lost function of his kinesthetic receptors

Defective nocireceptors

-Can have a congenital insensitivity to pain -Miss C. felt no pain when parts of her body were subjected to strong electric shock, to hot water at temperatures that usually produce reports of burning pain, or to prolonged ice-bath. She could not remember ever sneezing or coughing. The gag reflex can only be elicited with great difficulty, and the corneal reflexes to protect the eyes were largely absent. Miss C had severe medical problems because of this she exhibited pathological changes in her knees hips and spine and underwent several orthopedic operations. Her surgeon attributed these changes to the lack of protection to joints usually given by pain sensations. She apparently failed to shift her weight when standing to turn over in her sleep or to avoid certain postures, which normally prevent inflammation of joints. Tragically, Miss C died at the age of 29 of massive infections that cannot be brought under control." In fact, these were internal infections of her hips. -During the last few weeks of Miss C's life, she actually started to experience pain for the first time in her life, and it was very excruciating pain originating from the sources of infection in her body. And we don't know why she started to experience pain at this point in time.

Somatosensory receptors

-Comprises peripheral afferents and specialized receptors subserving interoceptive (internal to body) , proprioceptive (joint, muscle) and cutaneous (exteroreceptive, external to the body) sensitivity

Amplitude

-Corresponds to our perception of loudness -High amplitude sounds = loud sounds -Low amplitude sounds = soft sounds

Frequency

-Corresponds to our perception of pitch -Wavelength of a particular sound -Low frequency sounds = long wavelengths, low pitched sound -High frequency sounds = short wave lengths, high pitched sound

Complexity

-Corresponds to our perception of timber -Simple sound = pure tone -Complex sounds = mix of frequencies, and high in timbre

Deafness

-Deafness is the partial or complete inability to hear. -Some people are born deaf, which is known as congenital deafness. -Many others begin to suffer from conductive hearing loss because of age, genetic predisposition, or environmental effects, including exposure to extreme noise (noise-induced hearing loss), certain illnesses (such as measles or mumps), or damage due to toxins (such as those found in certain solvents and metals).

Endogenous attention (top-down processes)

-E.g: checking the time; look at the clock. -Internal decisions --> change direction of eyes to clock to see what time it is

Monoaural cues

-Each pinna interacts with incoming sound waves differently, depending on the sound' source relative to our bodies -.This interaction provides a monaural cue that is helpful in locating sounds that occur above or below and in front or behind us. -The sound waves received by your two ears from sounds that come from directly above, below, in front, or behind you would be identical; therefore, monaural cues are essential

Receptors

-Each sensory system has cells that transduce energy from the outside world into a neural response: Receptors -Within a single sensory system (e.g., somatosensory system), there are classes of receptors that are particularly sensitive to one stimulus (e.g., heat) but not to another (e.g., muscle stretch) in the somatosensory system

Presbycusis

-Fact that as we age, our ability to detect higher frequency sounds becomes poorer and poorer -18-24 year olds can detect a much wider range of frequencies of sounds than 50-59 year olds, and people less than 18 can detect even higher frequency sounds -Created a ring tone: only those individuals under the age of 18 can hear --> use phones in class and be able to hear when they got a text, and teachers who were older and were not able to hear the high frequency sound couldn't hear it

Inattentional blindness

-Famous gorilla video that Daniel Simons produced -When you're not attending to something, viewers asked to count number of passes between a ball in various passes in a video, they fail to notice a gorilla has wandered across the screen b/c they are busy paying attention to passes of the ball -We are unaware of things in our environment we are not directly paying attention to

Somatosensory homunculus

-First documented by Wilder Penfield through 1930s and 1950s -Mapping of the primary somatosensory cortex which lies just posterior to your central fissure -This is a somatotopic organization, just like the visual system had a retinotopic organization and the auditory system had a tonotopic organization -However, it's not a perfect representation of the surface of the body. -What you'll see is that there is a disproportionate representation of certain parts of the body. And those parts of the body that are disproportionately represented are those that receive more somatosensation. -So for example, your lips and mouth have a lot of cutaneous somatosensory receptors, and therefore, the somatosensory cortex has a disproportionate amount of area dedicated to it.

Cochlea

-Fluid, major component of the inner ear -Tightly wound structure, but if you were to unwind it it would be extended with 2 ends: one end would contain the oval window --> ossicles will bang on when the eardrum is activated by a sound and so a sound will enter the ear drum and cause the ossicles to vibrate, which will cause the oval window to cause pressure within the cochlea

Outer hair cells

-Form an elaborate feedback system that either helps to protect your hearing or helps to amplify sounds that are very weak in the environment -Does this by tightening the tectorial membrane, to reduce it's movement and protect your hearing -It can also loosen the tectorial membrane to increase movement and increase perception of weak sounds

Gestalt meaning

-Form or pattern, reflects the idea that the world is different from the sum of its parts

Conductive hearing loss

-Given the mechanical nature by which the sound wave stimulus is transmitted from the eardrum through the ossicles to the oval window of the cochlea, some degree of hearing loss is inevitable. -With conductive hearing loss, hearing problems are associated with a failure in the vibration of the eardrum and/or movement of the ossicles. These problems are often dealt with through devices like hearing aids that amplify incoming sound waves to make vibration of the eardrum and movement of the ossicles more likely to occur.

Papillae

-Gustatory system made up of papillae which have substructures known as taste buds -Each taste bud is comprised of a large number of taste receptors and each taste receptors sends an afferent nerve fiber (an axon) into the CNS

Controlling movement and reflexes and vestibular system

-In addition to maintaining balance, the vestibular system collects information critical for controlling movement and the reflexes that move various parts of our bodies to compensate for changes in body position. -Therefore, both proprioception (perception of body position) and kinesthesia (perception of the body's movement through space) interact with information provided by the vestibular system. -These sensory systems also gather information from receptors that respond to stretch and tension in muscles, joints, skin, and tendons. -Proprioceptive and kinesthetic information travels to the brain via the spinal column. Several cortical regions in addition to the cerebellum receive information from and send information to the sensory organs of the proprioceptive and kinesthetic systems.

Auditory canal

-In outer ear

Pinna

-In outer ear -Visible part of the ear that protrudes from our heads

Neuropathic pain

-In some situations, pain results from damage to neurons of either the peripheral or central nervous system. -As a result, pain signals that are sent to the brain get exaggerated. This type of pain is known as neuropathic pain.

Deaf culture

-In the United States and other places around the world, deaf people have their own language, schools, and customs. -This is called deaf culture. In the United States, deaf individuals often communicate using American Sign Language (ASL); ASL has no verbal component and is based entirely on visual signs and gestures. -The primary mode of communication is signing. One of the values of deaf culture is to continue traditions like using sign language rather than teaching deaf children to try to speak, read lips, or have cochlear implant surgery. -When a child is diagnosed as deaf, parents have difficult decisions to make. Should the child be enrolled in mainstream schools and taught to verbalize and read lips? Or should the child be sent to a school for deaf children to learn ASL and have significant exposure to deaf culture?

Olfactory bulb

-In the olfactory system, there is an extention of the brain known as the olfactory bulb -From the olfactory bulb extend dendrites into the nasal cavity and on these dendrites the receptor proteins for the olfactory system exist

Somatosensory system

-Large number of receptor types; traduces a variety of mechanical stimuli (e.g., light touch, hair deformation, vibration, temperature, tissue destruction, muscle stretch) -More receptor types that auditory and visual system

Somatosensory cortex

-Located in the parietal lobe and the amount of space dedicated to a body part corresponds to the degree of sensitivity

Skin receptors

-Mechanoreceptors: respond to mechanical stimulation or pressure -Skin contain a wide variety of receptors

Inner hair cells

-Mediate what we most commonly think of as sound perception/our everyday experience of sound -Tranduces mechanical energy from fluid motion within cochlea into a neural signal which his carried through the cochlea nerve into the brain

Mitral cells

-Mitral cells receive their input from the glow glomeruli -Each glomerulus receives its input from each type of olfactory receptor of a particular type -Conglomerates information from the nasal cavity about a particular olfactory sensation and the mitral cells carry info from the glomeruli into the central nervous system -Olfactory receptors have their dendrites within the nasal cavity and send their axons to the glomeruli

How we taste

-Molecules from the food and beverages we consume dissolve in our saliva and interact with taste receptors on our tongue and in our mouth and throat. -Taste buds are formed by groupings of taste receptor cells with hair-like extensions that protrude into the central pore of the taste bud. -Taste buds have a life cycle of ten days to two weeks, so even destroying some by burning your tongue won't have any long-term effect; they just grow right back. -Taste molecules bind to receptors on this extension and cause chemical changes within the sensory cell that result in neural impulses being transmitted to the brain via different nerves, depending on where the receptor is located. -Taste information is transmitted to the medulla, thalamus, and limbic system, and to the gustatory cortex, which is tucked underneath the overlap between the frontal and temporal lobes

Both taste and smell are chemical senses because...

-Molecules need to physically bind to receptors to induce a change in neural activity

Ear drum

-Most important component of outer ear -Also known as tympanic membrane -Converts sounds in air into physical motion that deflects the bones that are in our middle ear

Treatments for pain relief

-Multiple treatment options for pain relief range from relaxation therapy to the use of analgesic medications to deep brain stimulation. - The most effective treatment option for a given individual will depend on a number of considerations, including the severity and persistence of the pain and any medical/psychological conditions.

Olfactory receptor cells

-Olfactory receptor cells are located in a mucous membrane at the top of the nose. -Small hair-like extensions from these receptors serve as the sites for odor molecules dissolved in the mucus to interact with chemical receptors located on these extensions. -Once an odor molecule has bound a given receptor, chemical changes within the cell result in signals being sent to the olfactory bulb: a bulb-like structure at the tip of the frontal lobe where the olfactory nerves begin. From the olfactory bulb, information is sent to regions of the limbic system and to the primary olfactory cortex, which is located very near the gustatory cortex

Figure-ground relationship

-One Gestalt principle is the figure-ground relationship. -According to this principle, we tend to segment our visual world into figure and ground. -Figure is the object or person that is the focus of the visual field, while the ground is the background. -As the figure shows, our perception can vary tremendously, depending on what is perceived as figure and what is perceived as ground. -Presumably, our ability to interpret sensory information depends on what we label as figure and what we label as ground in any particular case, although this assumption has been called into question

Kinesthetic receptors

-Other types of mechanoreceptors within our muscles, tendons, and joints -Play an important role in the sense of where one's limbs are, and what kinds of movements are being made e.g: touch nose with fingertip --> mediated through a very complex set of feedback from your joints and muscles that is mediated through kinesthetic receptors Your kinesthetic receptors allow you to know where in space your limbs are at any given point in time. Allows you to touch your nose in the absense of visual input

Pain perception

-Pain is an unpleasant experience that involves both physical and psychological components. Feeling pain is quite adaptive because it makes us aware of an injury, and it motivates us to remove ourselves from the cause of that injury. In addition, pain also makes us less likely to suffer additional injury because we will be gentler with our injured body parts.

Inflammatory pain

-Pain that signals some type of tissue damage

Treatment for phantom limb pain

-Perhaps if we showed a person with their phantom limb pain their intact phantom limb in a desirable position or in a non-crushed state that the pain itself would actually be alleviated -Put person in front of mirror. See the phantom limb -In some cases this worked, if you created a situation where the person could see their intact limb where their phantom limb should be, it helped alleviate their phantom limb pain -Likewise, more recently people have developed techniques of visual imagery that are useful for the treatment of phantom limb pain. -That is, you have the person with the phantom limb imagine or visualize their phantom limb as being in a comfortable position and/or in an intact state. And this helps reduce their pain.

Tonotopic organization in the primary auditory cortex (A1)

-Primary auditory cortex is where sound information ultimately travels -Primary auditory cortex = between temporal lobes and frontal and parietal lobes -One of of the primary auditory cortex, the cells are maximally responsive to low frequency sounds and at the other end, the cells are maximally responsive to high frequency sounds

Receptor types

-Receptor types vary across sensory systems -Systems differ in how many receptor types they have Visual system: 2 broad classes of receptors (rods and cones); that collectively traduce light energy of different wavelengths Auditory system: 2 classes of receptors: inner and outer hair cells of the cochlea; traduce mechanical energy into neural signals

Transduction of Mechanical Energy

-Resting position, basillar membrane is flat -When you receive sound information travelling down leength of cochlea via fluid motion, the basiliar and tectorial membranes are displaced -Displacement causes a shearing force on the sterocilia that are on the hair cells, which is what is tranduced into a neural signal -Has an upward and a downward phase

Organ of Corti

-Runs the length of the cochlea -Contains the hair cells which are the transducers of mechanical energy into neural energy -2 types of hair cells: outer hair cells and inner hair cells -Both sets of hair cells lie on the basilar membrane and the outer hair cells are attached to the tectorial membrane -Inner hair cells lie just below the tectorial membrane

Phantom Limbs

-Sensation of having a limb that has been amputated -Fairly common amongst those that have had amputations of limbs either arms of legs -Phantom limb pain = sensation of having pain in one's phantom limb. Nature of this pain is such that it is either reminiscent of the injury that caused amputation, or reminiscent of what happens when one is lying on the couch for too long on one's arm. And when one does so, one usually ends up experiencing some mild pain that causes one to shifts one body. Reminiscent of being in a position too long. Contractions in muscles in their phantom limb that they cannot relax --> limb being curled up into awkward position that is going them severe pain

Change blindness

-Shown an image for four seconds interspersed with a gray screen, followed by another image for four seconds that is somehow different from the first image, again followed by a gray screen so that you basically have a flicker phenomenon. -That is, one image comes on briefly, then there is a flicker, then the second image comes on, then there's a flicker,than the first image comes on, and so forth. -Under those circumstances you will find it very, very difficult to actually register what is different between the two images. So this phenomenon is known as change blindness. -The fact that we struggle with change blindness is a testament to the notion that we are under the impression that we are aware of far more than we actually appear to be

Ossicles

-Small bones in our middle ear causes a change in the fluid within the cochlea -3 tiny bones -Named the malleus (or hammer), incus (or anvil), and the stapes (or stirrup) -Connects ear drums to cochlea

Stereocilia

-Small threadlike protusions on top of the hair cels -Responsible for converting mechanical energy into a neural signal

Congenital insensitivity to pain or analgesia

-Some individuals are born without the ability to feel pain. This very rare genetic disorder is known as congenital insensitivity to pain (or congenital analgesia). -While those with congenital analgesia can detect differences in temperature and pressure, they cannot experience pain. -As a result, they often suffer significant injuries. -Young children have serious mouth and tongue injuries because they have bitten themselves repeatedly. Not surprisingly, individuals suffering from this disorder have much shorter life expectancies due to their injuries and secondary infections of injured sites

How sound waves travel

-Sound waves travel along the auditory canal and strike the tympanic membrane, causing it to vibrate pinna;ear canal; tympanic membrane; ossicles; cochlea; auditory nerves -The vibration results in movement of the 3 ossicles -As the ossicles move, the stapes (ossicle) presses into a thin membrane of the cochlea known as the oval window, and the fluid inside the cochlea begins to move, which in turn stimulates hair cells, which are auditory receptor cells of the inner ear embedded in the basilar membrane which is a thin strip of tissue within the cochlea

Cutaneous senses

-Tactile (pressure, vibration, texture) -Thermal -Pain -Itch

Chemical Senses

-Taste (gustation) and smell (olfaction) are called chemical senses because both have sensory receptors that respond to molecules in the food we eat or in the air we breathe. There is a pronounced interaction between our chemical senses. For example, when we describe the flavor of a given food, we are really referring to both gustatory and olfactory properties of the food working in combination

Gestalt psychology

-The brain creates a perception that is more than simply the sum of available sensory inputs, and it does so in predictable ways -Gestalt psychologists translated these predictable ways into principles by which we organize sensory information -Very influential in the area of sensation and perception

Inner ear components

-The inner ear contains the semi-circular canals, which are involved in balance and movement (the vestibular sense), and the cochlea. The cochlea is a fluid-filled, snail-shaped structure that contains the sensory receptor cells (hair cells) of the auditory system

Place theory

-The place theory of pitch perception suggests that different portions of the basilar membrane are sensitive to sounds of different frequencies. -Suggests that auditory perception of a particular frequency is achieved by auditory neurons that are organized by pitch preference in the basilar membrane -More specifically, the base of the basilar membrane responds best to high frequencies and the tip of the basilar membrane responds best to low frequencies. -Therefore, hair cells that are in the base portion would be labeled as high-pitch receptors, while those in the tip of basilar membrane would be labeled as low-pitch receptors

Temporal Theory

-The temporal theory of pitch perception asserts that frequency is coded by the activity level of a sensory neuron. -This would mean that a given hair cell would fire action potentials related to the frequency of the sound wave. -While this is a very intuitive explanation, we detect such a broad range of frequencies (20-20,000 Hz) that the frequency of action potentials fired by hair cells cannot account for the entire range. -Because of properties related to sodium channels on the neuronal membrane that are involved in action potentials, there is a point at which a cell cannot fire any faster

Vestibular sense

-The vestibular sense contributes to our ability to maintain balance and body posture. -The major sensory organs (utricle, saccule, and the three semicircular canals) of this system are located next to the cochlea in the inner ear. -The vestibular organs are fluid-filled and have hair cells, similar to the ones found in the auditory system, which respond to movement of the head and gravitational forces. -When these hair cells are stimulated, they send signals to the brain via the vestibular nerve. Although we may not be consciously aware of our vestibular system's sensory information under normal circumstances, its importance is apparent when we experience motion sickness and/or dizziness related to infections of the inner ear

Sound waves

-There is not a one-to-one relationship between the sounds in our environment and our perception of sounds -Terms used to define sound are different that terms used to define our PERCEPTION of sound

Variation in sensitivity of olfactory system of different species

-There is tremendous variation in the sensitivity of the olfactory systems of different species. -We often think of dogs as having far superior olfactory systems than our own, and indeed, dogs can do some remarkable things with their noses. -There is some evidence to suggest that dogs can "smell" dangerous drops in blood glucose levels as well as cancerous tumours. -Dogs' extraordinary olfactory abilities may be due to the increased number of functional genes for olfactory receptors (between 800 and 1200), compared to the fewer than 400 observed in humans and other primates. -Many species respond to chemical messages, known as pheromones, sent by another individual. -Pheromonal communication often involves providing information about the reproductive status of a potential mate. -So, for example, when a female rat is ready to mate, she secretes pheromonal signals that draw attention from nearby male rats. -Pheromonal activation is actually an important component in eliciting sexual behavior in the male rat. -There has also been a good deal of research (and controversy) about pheromones in humans -Pheromones = chemical sense, detected via olfaction

Glomeruli assist in

-Transmitting olfactory information to the brain

Law of continuity or good continuation and closure

-Two additional Gestalt principles are the law of continuity (or good continuation) and closure. -The law of continuity suggests that we are more likely to perceive continuous, smooth flowing lines rather than jagged, broken lines (Fig. 4). The principle of closure states that we organize our perceptions into complete objects rather than as a series of part

Sound localization

-We can localize sound and space around us, which is done by the brain's ability to calculate interaural time difference -Localizing sound is similar to the way we perceive depth in our visual fields. -Like the monocular and binocular cues that provide info about depth, the auditory system uses both monoaural (one-eared) and binaural (two-eared) cues to localize sound -Interaural time difference is the time difference that exists between a sound reaching one ear and the sound reaching your other ear -If sound in environment originates in left hand side, that sound reaches your left ear before the right ear and your brain computes with the help of the inferior colliculus, which is part of the tectum, the location of a a particular sound based on that interaural time different -Tectum is part of the mesencephalon, the midbrain

Principle of similarity

-We might also use the principle of similarity to group things in our visual fields. -According to this principle, things that are alike tend to be grouped together. -For example, when watching a football game, we tend to group individuals based on the colors of their uniforms. When watching an offensive drive, we can get a sense of the two teams simply by grouping along this dimension.

Sensorineural hearing loss

-When the hearing problem is associated with a failure to transmit neural signals from the cochlea to the brain, it is called sensorineural hearing loss. -One disease that results in sensorineural hearing loss is Ménière's disease. -Ménière's disease results in a degeneration of inner ear structures that can lead to hearing loss, tinnitus (constant ringing or buzzing), vertigo (a sense of spinning), and an increase in pressure within the inner ear -This kind of loss cannot be treated with hearing aids, but some individuals might be candidates for a cochlear implant as a treatment option. -Cochlear implants are electronic devices that consist of a microphone, a speech processor, and an electrode array. The device receives incoming sound information and directly stimulates the auditory nerve to transmit information to the brain.

Pitch perception theories

1) Temporal theory 2) Place theory

Pitch perception theories

1) Temporal theory 2) Place theory Both theories explain different aspects of pitch perception. At frequencies up to about 4000 Hz, it is clear that both the rate of action potentials and place contribute to our perception of pitch. However, much higher frequency sounds can only be encoded using place cues

2 types of endogenous attention

1) Volitional --> decisions, look at clock to figure out what time it is 2) Mandatory --> phenomenon of attention that are determined not by volition (will to figure out some piece of information) but by the way your neural machinery works. Not something you are willing but determined by the nature of your visual system

Anatomy of the Human Ear

3 major components: 1) Outer ear 2) Middle ear 3) Inner ear