biopsych exam #3

brain networks involved in attention

*BILATERAL FRONTOPARIETAL DORSAL ATTENTION NETWORK:* - the *dmPFC* and *frontal eye fields* and the *posterior parietal cortex* - responsible for top-down voluntary direction of attention *RIGHT-BIASED FRONTOPARIETAL VENTRAL ATTENTION NETWORK:* - the *ventrolateral PFC* and *temporoparietal junction* are activated during bottom-up involuntary direction of attention

bottom-up vs. top-down perceptual processing

*BOTTOM-UP PROCESSING:* building up a mental representation of the world based on information received by the senses and assembled through successive processing steps - predominates in children - very effortful, why kids need more sleep *TOP-DOWN PROCESSING:* our brain constructs representations of the world and then uses information from the senses to support or refute these constructs - predominates in adults - start to develop *predictions* - predictions don't always match - ex: coffee cup full of lemonade, escalator example

defining cogniton

* cognition:* the process of generating, perceiving, recognizing, understanding and organizing thoughts - thoughts are mental ideas or images, real or imagined cognition involves the ability to: - identify stimuli - focus on certain stimuli - plan meaningful responses to stimuli - ignore irrelevant stimuli cognition = thinking

cortical processing networks

*CENTRAL EXECUTIVE NETWORK:* - dlPFC and posterior parietal cortex - involved in conscious thought and rational decision-making in response to external cues *DEFAULT MODE NETWORK:* - medial prefrontal cortex, precuneus/medial parietal cortex, and temporal cortex - internally driven network involved in fantasizing, mind wandering, daydreaming, reminiscing, free associating, creativity, etc. *both the central executive and default mode network can be important for problem solving!!!* we can make both good and bad decisions based on emotions and logic impulse control = definitely related to genetics but can also be changed

convergent vs. divergent intelligence

*CONVERGENT INTELLIGENCE:* - the ability to apply memory or reasoning skills to come up with the correct answer - depends most on memory and language/math/logic ex: multiple choice test, trivia contests, math problems *DIVERGENT INTELLIGENCE:* - the ability to use unconventional knowledge or creative approaches to come up with novel solutions - depends on executive functions and generation of new ideas or plans - creativity ex: brainstorming, inventing, creating, innovating, composing, creative writing, art

psychophysiology

*ELECTROENCEPHALOGRAPHY (EEG):* the recording of electrical activity of the brain through scalp electrodes both the timing and amplitude of the waveforms provide information on cognitive functioning EEG can tell us about the TIMING AND MAGNITUDE of neural activity in the brain but NOT WHERE this activity is occurring

intelligence tests and general intelligence

*GENERAL INTELLIGENCE:* - the idea that while there may be different kinds of intelligence, there is a general intelligence underlying all of them - ttempts to quantify general intelligence have been extremely difficult because of cultural and other biases in the proposed tests Nevertheless, performance on general IQ tests is associated with several measures of brain size/function, including: - faster neuronal conduction velocity - lower brain energy utilization - greater brain volume/thickness in frontal, temporal, and parietal cortices (PET scans)

damage to the basal ganglia

*HYPERKINETIC SYMPTOMS AND THE DIRECT PATHWAY:* involuntary and/or excessively forceful movements caused by damage to the *indirect* pathway (Huntington's chorea, Tourette's Syndrome tics, obsessive behaviors in OCD, the mania of schizophrenia) *HYPOKINETIC SYMPTOMS AND THE INDIRECT PATHWAY:* rigidity & decreased movement production caused by damage to the *direct* pathway (Parkinson's Disease) - inhibitory *basal ganglia regulates the likelihood and forcefulness of movements by modulating the drive or motivation the frontal cortex receives* depending on what's happening, you may need to increase or decrease drive the lowest force movement is no movement at all basal ganglia is the amount of force - ex: bag empty vs bag with rocks

brain regions involved in attention

*LOCUS COERULEUS & BASAL FOREBRAIN:* - shifting from distributed to focused attention, receive input from ACC (anterior cingulate cortex) and PFC (prefrontal cortex) *PARIETAL & TEMPORAL ASSOCIATION CORTICES:* - exteroceptive visual and auditory attention *INSULAR CORTEX:* - interoception and internal attention *DORSOMEDIAL PREFRONTAL CORTEX (dmPFC) & FRONTAL EYE FIELDS:* - top-down attention - lower outside of brain

brain imaging

*MAGNETIC RESONANCE IMAGING (MRI):* measures SIZE or VOLUME of different brain regions *FUNCTIONAL MAGNETIC RESONANCE IMAGING (fMRI):* measures changes in BLOOD FLOW to brain regions to quantify the amount as well as the localization of brain activity *POSITRON EMISSION TOMOGRAPHY (PET):* measures GLUCOSE utilization to quantify the amount as well as the localization of brain activity both fMRI and PET can tell us WHERE and HOW MUCH brain activity is occurring but cannot tell us how fast the brain is responding more bloodflow - more activity

*NOT ON EXAM* neurodiversity and the genetics of cognition

*NEURODIVERSITY:* - the approach to learning and disability which suggests that diverse neurological conditions appear as a result of normal variations in the human genome - a key tenet of neurodiversity is that most behavioral traits represent a continuum upon which we all fall - in addition, traits or behaviors which may seem maladaptive actually may have beneficial qualities now or did in the past *HUNTER-FARMER HYPOTHESIS OF ADHD:* - having a distributed attention style was adaptive for hunter-gatherers but may be less so for "farmers" *SHAMANISTIC HYPOTHESIS OF SCHIZOPHRENIA:* - seeing visions and hearing voices may have been beneficial for shamans in tribal societies

psychological tests of cognitive function

*PERCEPTION TESTS:* - how long it takes to recognize an object & how accurate *ATTENTION TESTS:* - how long can a subject focus on a task *MEMORY TESTS:* - how long, and how accurately can a subject remember numbers, symbols, words, etc. *EXECUTIVE FUNCTION TESTS:* - 1)problem solving tests—putting together puzzles, etc. - 2) creativity tests (ex: what can you do with this brick) - 3) impulse control tests—Erickson Flanker Task, Stroop Task (identify the color the word is printed in as quickly & accurately as you can)

4 main components of cognition

*PERCEPTION* - the ability to recognize & interpret sensory stimuli *ATTENTION:* - ability to sustain concentration on a particular object, action or thought *MEMORY:* - the ability to store & recall information *EXECUTIVE FUNCTIONS:* - abilities that enable goal-oriented behavior, such as the ability to plan and execute a goal, impulse control, problem solving, coming up with new ideas, etc. (this is what makes us different from other animals)

main structures involved in neural control of movement

*PREFRONTAL CORTEX:* initiates movement goals, plans, ideas (the CEO) *PREMOTOR CORTEX:* creates specific movement pattern or sequence (the manager) *MOTOR CORTEX & SPINAL CORD:* send movement information out to muscles & other brain regions *MUSCLES:* carry out movements *BASAL GANGLIA & CEREBELLUM:* detects and corrects errors in movement

the neurobiology of planning, decision-making and impulse control—the tale of two PFCs

*THE DORSAL/DORSOLATERAL PREFRONTAL CORTEX(dlPFC)* plays critical roles in: - planning and decision-making in response to *external cues* and that often reflect *delayed gratification and low risk* - the *rational side* - inhibiting impulsive decisions by modulating activity of the: *THE MEDIAL/VENTROMEDIAL PREFRONTAL CORTEX*plays a critical role in - decision-making in response to *internal cues* like hunger, taste, emotion, preference, etc. that often reflect *short-term gain and/or higher risk*—the *emotional* side

4 types of somatosensory receptors

*THERMORECEPTION:* - skin - 2 hot and 1 cold *NOCICEPTION:* - skin and organs - pain: temperature, chemical, mechanical *HAPSIS:* (touch) - skin - itch, light touch, deep pressure, vibration, stretch, texture *PROPRIOCEPTPION:* - muscles, tendons, and joints - body awareness, muscle stretch and joint angle

language areas of the brain

*WERNICKE'S AREA:* understanding literal spoken language *ANGULAR GYRUS:* understanding written language - *ALEXIA:* lose ability to read - damage to angular gyrus (must result to books on tape, sign language) *BROCA'S AREA:* responsible for speech production - motor area; opening mouth, moving tongue - *BROCA'S APHASIA*: hard to produce/understand complex sentences *RIGHT TEMPORAL POLE:* responsible for interpreting PROSODY (pitch/volume cues often important in detecting lies, sarcasm, innuendo, humor & other forms of *insincere communication*) - interpreting prosody is something we develop it was thought that every part of the brain can do anything - Wernicke and Broca first discovered specialization

the photoreceptors and color

- *3 different types of cones*: blue, green, and red, each specialized to be optimally stimulated by a particular wavelength - convergence of color information takes place in the ganglion cells and cortex similar to that of shape to allow us to add/mix input from different cones (purple is activation of red and blue cones)

error detection and problem solving

- *THE ANTERIOR CINGULATE CORTEX* is a set of neurons that is activated by sensory input that is novel, complex, conflicting, aversive, or unrewarding - the ACC thus functions as an error warning and detection system - the ACC sends output to the *prefrontal cortex, motor cortex, and autonomic nervous system* to develop a new plan the ACC becomes active when we're anticipating a problem only does hard tasks and fixing errors

somatosensory neurons

- *UNIPOLAR NEURONS* with one long dendrite that connects directly to the axon - connect to the spinal cord via spinal nerves - *DORSAL ROOT GANGLIAN* contains cell bodies of sensory neurons

multisensory integration - adding other sensory inputs to precisely identify "what"

- *combining of different sensory inputs to fully identify an object* - multisensory integration centers are distributed throughout the cortex - neurons in these areas receive *multimodal input* -they receive axons from neurons from more than one sensory modality (multimodal input: converging sound and visual) - may also be responsible for *SYNESTHESIA* or the ability to experience senses across sensory modalities (ex: sounds have colors, tastes - excessive connections)

human smell & behavior

- *nearly all reactions to smell are learned*—babies show no difference in reaction to good vs. bad smells, there are no universally recognized smells across cultures - mothers can identify blood offspring but not stepchildren, and siblings can identify blood siblings but not half- or step-siblings—may be responsible for the *WESTERMARCK EFFECT* - women tend to find the smell of men who are genetically different from them more pleasant, which may be a mechanism by which genetic variation is increased during mate selection

attention

- *selective allocation of awareness to part of the sensory environment* - attention can be FOCUSED or DISTRIBUTED - attention can be EXTEROCEPTIVE, or external, which can involve any of the senses, or INTEROCEPTIVE or internally directed on how we are feeling both physically and emotionally - attention can be top-down (directed consciously by us) or bottom-up (directed by information from our senses) attention is a constrained resource

the association cortex

- all regions of the cerebral cortex EXCEPT the primary motor and sensory cortex areas - includes the prefrontal and premotor cortex in the frontal lobe as well as regions in the parietal, temporal and occipital lobes - includes the inferior temporal cortex ("what" visual pathway) and parietal cortex ("where" visual pathway) human beings have a bigger association cortex than mice which is probably why we have more complex thoughts

spinal cord

- axons from *UPPER MOTOR NEURONS* from motor cortex continue to descend to the spinal cord - upper motor neurons synapse onto *LOWER MOTOR NEURONS* (spinal cord to muscle) - axons of lower motor neurons exit spinal cord via the peripheral nerve and synapse on muscle fibers - the spinal cord also contains *CENTRAL PATTERN GENERATORS* (circuits of interneurons that alternatingly activate lower motor neurons down the limbs on both sides of the body to produce rhythmic, cyclic movements like walking) - input from upper motor neurons can activate, inhibit, or modify activity of CPGs

location in the striate cortex

- axons from LGN (lateral geniculate nucleus) neurons extend to the striate cortex - information from the top of the visual field is sent to the bottom of the striate cortex and vice versa - information from the left visual field is sent to the right striate cortex and vice versa - information from the center of the visual field is sent into the center while information from the periphery (outside edge area) is sent more anteriorly (front area) - the fovea has a larger representation than peripheral retinal areas 1/3 of brain dedicated to visual information

sensory processing & the sensory cortex

- changes in action potential firing of sensory receptor neurons is ultimately relayed to specific cortical regions specialized for each sense - processing occurs in the *PRIMARY SENSORY CORTEX*, but continues in secondary and tertiary cortical centers - the *location* of the primary sensory cortex for each sense is hard-wired and the same for everyone - however, the *size/extent* of each region is determined by experience—amputees, blind, expertise - also, different primary sensory cortex regions can be adapted for use by another sense sensory processing - where we start, not where we end vision is processed in the back of brain in all vertebrae

color blindness (dichromacy)

- inability to sense *one* specific color - genetic lack of one type of cone results in inability to perceive color in that range - about 8% of men and about 0.5% of women have some form of color blindness trichromacy refers to regular 3-color human vision trichromate vision: regular vision (all 3 cones)

neurophysiology of the olfactory system

- chemical odorants enter the nasal cavity and dissolve in the olfactory mucosa - odorants bind to receptors on the surface of olfactory receptor cells - odorant binding causes opening of Ca2+ channels and depolarization, which produces action potentials on sensory neurons - there are about 400 different types of olfactory receptors found on different types of olfactory receptor neurons in the human nose that respond to different smells things don't taste as good when we're sick because our mucus layer is thicker so we can't smell the food as well; we can actually taste just fine

neurophysiology of gustation

- chemicals bind to receptors or enter a channel on taste bud receptor cells - binding to receptors or movement through channel opens Na+ channels or closes K+ channels - opening of Na+ channels or closing of K+ channels depolarizes receptor cells - depolarization results in release of neurotransmitter onto sensory neurons - NT release induces action potentials on sensory neurons

anatomy of gustation

- chemicals enter the mouth and are dissolved in saliva - chemicals dissolved in saliva access taste receptors located in taste buds found primarily on the tongue - the mouth also has receptors for touch and temperature - taste buds down esophagus and into stomach - taste primes our digestive system to it'll know what do do - mouth is part of somatosensory area

skeletal muscle

- consists of long, cylindrical cells called muscle fibers that produce movement by contracting or shortening and pulling against bones - each muscle fiber gets innervated by a single motor neuron - however a single motor neuron can innervate multiple muscle fibers—*MOTOR UNIT* - *AGONISTS* are muscles that contract to produce movement - *ANTAGONISTS* are muscles that oppose the contracting muscle by passively lengthening the more movement, the more action potential firing

the retina

- consists of sensory receptors (*photoreceptors*) and the sensory neurons that synapse with them BLIND SPOT: region containing no photoreceptors because the sensory neuron axons exit the eye here as the optic nerve but the other eye, and photoreceptors around each blind spot, "fill in" missing visual info FOVEA: region containing the largest density of photoreceptors; vision is actually sharpest here; makes up <1% of visual field but eye movements called *SACCADES* driven by neurons in the midbrain move your fovea around your visual field to give a bigger more detailed picture - opposite of blind spot - the only place where you're legally not blind Saccades are controlled by the FRONTAL EYE FIELDS (cortex) and the SUPERIOR COLLICULUS (midbrain) - saccades are color vision - both voluntary and involuntary (hearing a loud noise) dark room → iris expands light room → iris shrinks

prefrontal cortex

- creates goals from external (lateral PFC) or internal (medial PFC) signals - the PFC then creates a plan for achieving this goal and decides if this plan of action is appropriate (*impulse control*) - does not specify the precise pattern of movements to be made—that is left to the premotor cortex - neurons in the prefrontal cortex send their axons to the PREMOTOR CORTEX lesions to the prefrontal cortex leads to impulsive or inappropriate behaviors - Phineas Gage

neurotransmitter alterations in ADHD

- decreased DOPAMINE signaling, which results in decreases in reward pathways that may cause children to seek out new stimuli for greater reward and *increase impulsivity* - decreased ACETYLCHOLINE and NOREPINEPHRINE signaling, which may *decrease attention* - increased GLUTAMATE signaling, which may globally *increase arousal* throughout the brain - *different subtypes of ADHD may be associated with larger or smaller changes in one or more of these neurotransmitters*

retinal ganglion cell receptive field

- each retinal ganglion cell receives input from a number of nearby bipolar cells, which receive input from a number of nearby photoreceptors - thus each ganglion cell has a discrete *receptive field* of photoreceptors which will be activated if light hits them and will activate that ganglion cell - the retina therefore consists of thousands of receptive fields

the visual system processes 3 components:

- form/shape - color - motion/lack of motion

the auditory cortex

- found in the SUPERIOR TEMPORAL CORTEX - processes complex patterns of sound; damage to this area doesn't result in total deafness but in inability to perceive complex patterns of sound - also receives input from other sensory cortical areas, memory areas, and frontal cortex that help us identify sources of sounds - *LATERALIZATION OF SOUND:* SPEECH & LANGUAGE are processed in the LEFT temporal auditory cortex and MUSIC is processed in the RIGHT temporal auditory cortex auditory cortex: distinguish tones patterns of sound: spoken language

basal ganglia

- group of nuclei in the forebrain - basal ganglia neurons *receive* input from the *MOTOR CORTEX* and the *SUBSTANTIA NIGRA* on motor behavior and from the *SENSORY CORTEX* on the success of motor behaviors - basal ganglia neurons send axons back to the motor cortex via the *THALAMUS*

neurophysiology of hair cells

- hair cells normally release neurotransmitter and produce action potentials on sensory neurons they synapse on - bending of hair cells one way opens K+ channels on hair cells - *opening of K+ channels DEPOLARIZES hair cells (brings positive charge ion in) (in these cells, K+ is higher OUTSIDE the cell in cholera!!! so K+ flows INTO cells)* [*MECHANICALLY-GATED ION CHANNEL* - depends on hair movement] - depolarization opens voltage-gated Ca2+ channels - influx of Ca2+ causes more NT to be released - rate of action potentials increases - as vibration waves pass through the cochlea, hair cells bend first one way then the other - bending one way opens the K+ channels, bending the other way closes them - this increases then decreases the release of NT and thus the action potential firing rate of the sensory neuron - *it is thus the PATTERN of neuronal firing that tells the nervous system how loud and what pitch a noise is* quantity of sound is related to amplitude sound - vibration of air molecules hairs bend back and forth depending on amplitude K+ channel on hair itself movement to right = opens more K+ channels movement to left = closes more K+ channels

processing shape in the inferior temporal cortex

- input from many different "line" neurons in the striate cortex converges via the ventral stream onto inferior temporal cortical neurons that then process lines into shapes - LOCAL CODING: some single inferior temporal cortex cells recognize specific shapes (ex: squares) -POPULATION CODING: for more complex images (faces, makes of cars, etc.), networks of neurons are activated - people with expertise in one visual concept (birds, cars, etc.) have more neurons dedicated to this topic - LATERALIZATION: words are processed in the left ITC, faces and places in the right ITC. Generic objects are processed in the left ITC, specific objects in the right ITC striate cortex line neurons → inferior temporal cortex to form shapes - striate cortex neurons with different line detection send axons that converge on single temporal cortex neurons - if both striate neurons are firing at a high rate simultaneously, they will cause the temporal cortex neuron to fire highest only when both striate neurons are active at the same time - this will therefore be a "+" neuron - other neurons might fire highest when a * or a box or a circle is present and the corresponding striate neurons are firing

line detection in the visual cortex

- input from several ganglion "spot" cells is summed and activates a single neuron in the temporal cortex - in this way, ganglion input, which provides information about "spots", is translated into "lines" or "bars" in the striate cortex - different neurons in the striate cortex respond to slightly different line orientations - neurons responding to lines in different parts of the visual cortex are arranged into columns in the visual cortex striate cortex - receive input from multiple retinal ganglion cells (spots) - putting together light spots (retinal ganglion) = we have lines library of line neurons dorsal = lines, ventro = dots ganglian cells - spots ; striate cortex - lines

multiple intelligences/kinds of intelligences

- linguistic - musical - logical-mathematical - spatial - bodily-kinesthetic - intrapersonal (one person, in yourself) - interpersonal these different intelligences often involve different brain regions - linguistic with temporal cortex language centers, mathematical/spatial with posterior parietal cortex, kinesthetic with somatosensory processing

rod vs cone convergence

- more rods converge on each bipolar neuron, and more rod bipolar neurons converge on each rod ganglion cell - RODS are important for sensing dim light, so MORE CONVERGENCE makes sense since it means rod retinal ganglion neurons will be activated if ANY of the rods get activated by light so there's HIGHER SENSITIVITY - CONES are important for fine detail discrimination, so LESS CONVERGENCE makes sense if we want a fine map of an object because it means HIGHER ACUITY low convergence → high acuity high convergence → high sensitivity the more sensors, the more likely to send a signal

hierarchal control of movement

- movement starts with a *goal* - this goal is operationalized into a pattern of movements for achieving the goal - this *pattern* of coordinated movements is converted into *activation* of the relevant muscles - sensory information provides *feedback* about the movement - errors have to be *detected* and *corrected* top-down directed process contralateral (moving right hand is signaled by left side of brain)

motion perception in the visual cortex

- moving objects activate different retinal ganglion receptive fields sequentially - convergence of retinal ganglion information allows neurons in the striate cortex to identify patterns of movement similar to how it detects lines motion perception - vector neurons

pathways to gustatory cortex

- neurons from taste buds send axons to neurons in the BRAINSTEM, which send axons to the THALAMUS which then project to the primary gustatory (taste) cortex, *the insular cortex* - information about "mouth feel", temperature, spiciness, etc., is sent to the *primary somatosensory cortex* - brainstem neurons also send axons directly to the AMYGDALA AND HYPOTHALAMUS that provide direct emotional and eating behavior input

pathways to the olfactory cortex

- olfactory receptor cells send axons to the *OLFACTORY BULB* and synapse on *MITRAL CELLS* - mitral cells send axons directly to the primary olfactory center, the *PIRIFORM CORTEX* - ***smell is the only sense that bypasses the thalamus*** - olfactory information is also sent to several areas of the brain, including the amygdala, hippocampus, and hypothalamus, involved in emotional behaviors, memory, and eating - *like taste, smell has strong and rapid effects on memory and emotion*

sensing light with photopigments

- photoreceptors contain a special pigment molecule called *RHODOPSIN* (rho = vitamin A) - when light strikes rhodopsin, it activates a G-protein - the activated G protein CLOSES a Na+ channel - closing the Na+ channel means less (+) charge flowing into the cell, hyperpolarizing it - hyperpolarization means decreased release of glutamate by the photoreceptor onto bipolar cells - *the more light hits the photoreceptor, the more Na+ channels will close, the more hyperpolarized the cell will be, the less glutamate will be released* in pitch darkness, photoreceptors are firing as much action potential as possible more light = fewer acton potential

premotor cortex

- produces complex movement patterns or sequences necessary to accomplish the task - the premotor cortex also contains *MIRROR NEURONS*, which are activated when a person does an activity and when they SEE the same action being done—may allow imitation and empathy - neurons in the premotor cortex send their axons to the MOTOR CORTEX lesions to the premotor cortex affects the ability to put together complex movements

the posterior parietal cortex

- receives visual input from the striate cortex via the dorsal "where" stream - also receives input from the motor, auditory, and somatosensory cortex that allow us to locate ourselves in space - sends output to motor cortex to facilitate movements, visual tracking 1/3 of brain dedicated to visual information where - relative to me and relative to other things

brain changes with ADHD

- reduced size and activity of the DORSOLATERAL PREFRONTAL CORTEX, which may reflect difficulties in decision making and impulse control - decreased size or activity of the ANTERIOR CINGULATE CORTEX, which may be associated with defects in error detection - decreased size or activity of the DORSOMEDIAL PREFRONTAL CORTEX and LOCUS COERULEUS, which may be associated with defects in attention - decreased size or activity of the BASAL GANGLIA, which is involved in motivation as well as inhibition of impulsive motor behavior (hyperactivity) - decreased AMYGDALA size and activity, which could contribute to problems with emotion regulation

flow of visual information into the brain

- retinal ganglion neurons send their axons to neurons of the LATERAL GENICULATE NUCLEUS of the thalamus - the lateral geniculate nucleus neurons sends their axons to neurons of the STRIATE CORTEX light into eye - photoreceptors - horizontal cells - bipolar cells - retinal ganglian cells - LGN (lateral geniculate nucleus in thalamus) - striate cortex (occipital cortex)

sensory reflexes

- sensory information entering the spinal cord synapses on lower motor neurons - activation of the stretch receptor causes activation of motor neurons, resulting in a twitch - reflexes allow us to respond much more rapidly than when we process sensory information in the brain What does testing our reflexes tell us? - tells us about how well our sensory and motor neurons are working but tells us nothing about the brain - sensory information entering the spinal cord synapses on lower motor neurons - activation of the stretch receptor causes activation of motor neurons, resulting in a twitch - reflexes allow us to respond much more rapidly than when we process sensory information in the brain - *testing of reflexes tells us about how well our sensory and motor neurons are working but tell us nothing about the brain*

somatosensory cortex

- sensory information enters spinal cord and travels to the BRAINSTEM and THALAMUS - thalamus sends information to the SOMATOSENSORY CORTEX - the somatosensory cortex is arranged topographically in a homunculus similar to the motor cortex - amputees often have phantom feelings in their missing limb because other parts of the somatosensory cortex take over the neurons representing the missing limb (renervate - new ones are still there, they're just repurposed)

neural relays

- sensory information is conveyed into the CNS via 3-4 neuron relays - each neuron changes the firing of the next neuron in the relay, which then gets sent to the next neuron - most sensory information is relayed through the *brainstem*, where some basic processing begins, and the *thalamus*, which acts as a relay station but also processes and filters information and modulates arousal (Grand Central)—damage to the thalamus usually results in *coma* thalamus also regulates motor movement

neural relay for hearing

- sensory neurons in the cochlea send axons to neurons in the BRAINSTEM - the brainstem is where differences in intensity and latency are sensed to determine where a sound is coming from - brainstem neurons send axons to neurons in the MIDBRAIN, which send axons to neurons in the THALAMUS, which send axons to the auditory cortex in the *SUPERIOR TEMPORAL CORTEX* - in all brain regions, sounds of different tone or pitch are arranged in an organized map simple things are processed lower

the inferior temporal cortex and "what"

- shape, color, and motion information converges on other neurons in the inferior temporal cortex and integrated— "It's brown with two white stripes, it's oval, and it's spinning and flying through the air, it must be a football" . It has two dots and a curve, it's a face - communication occurs between medial temporal lobe neurons and hippocampal memory neurons which allows us to RECOGNIZE objects - communication also occurs with the speech and language centers in the temporal lobe that allow us to NAME objects

the 5 senses

- sight/vision*: light signals are converted into action potentials - taste/gustation*: chemical signals are converted into action potentials - smell/olfaction*: chemical signals are converted into action potentials - hearing/audition*: mechanical/physical signals (air pressure waves) are converted into action potentials - touch/somatosensation**: physical signals (touch, temperature, pain) are converted into action potentials *exteroceptive ** both exteroceptive and interoceptive we have temperature and touch receptors in both places sensory receptors are cells, not proteins

brain changes with schizophrenia

- smaller brain size and/or larger ventricles - specifically, the prefrontal cortex, cingulate, hippocampus, and medial temporal cortex are smaller, regions associated with cognition, memory, and emotion regulation

anatomy of the ear

- sound waves travel into the EAR and into the EAR CANAL - sound causes the EARDRUM to vibrate - this causes the 3 bones of the middle ear to vibrate also - the bones cause vibrations to be conveyed into the COCHLEA - within the cochlea, vibration causes HAIR CELLS to bend

the cerebellum and movement correction

- the cortex sends movement information down spinal cord to muscles - the cerebellum also receives a copy of this motor program from the cortex via the inferior olive - cerebellum compares the motor program with sensory feedback about the movement - cerebellum then sends corrective feedback to the premotor cortical neurons so that the next time the motor program is sent down it is adjusted based on this sensory feedback and experience What do you think happens to the dart throwing ability of people with cerebellar damage? - people with cerebral damage tend not to improve their throwing accuracy with practice like people without cerebral damage cerebellum = pattern success, accuracy

perception depends on:

- the nature of the sensation - context in which sensory events take place - our emotional state - past experiences and memories - perception requires attention - *perception is almost always more critical to understanding behavior than sensation/reality* dress: what differed was how their brain processed the sensory information perception is not the same as sensation

motor cortex

- the neurons of the motor cortex are arranged in groups that produce movement of key body parts - *MOTOR HOMUNCULUS:* a representation of the motor cortex map, greater size of hands, lips & tongue reflect greater motor innervation of these parts due to their finer movement abilities - the size and complexity of different regions is determined by experience—musicians, athletes have larger representations for body parts involved with their talent - motor cortex neurons send their axons down through the BRAINSTEM as well as to the BASAL GANGLIA AND CEREBELLUM lesions to the motor cortex causes *PARALYSIS* (inability to carry out specific movements) - paralysis can be in only 1 part of the brain or body or more than 1

convergence

- there is some convergence of information in the relay—neurons at each level receive input from more than one sensory receptor - convergence *decreases ACUITY* (how precisely we can identify where a signal arose from) - but convergence *increases SENSITIVITY* (how likely we are to detect a signal) - convergence also *increases COMPLEXITY* (it allows downstream neurons to combine information from multiple upstream neurons) convergence = spatial summation acuity vision = eye chart at the doctor's gain sensitivity with convergence, but decreases activity

the striate occipital cortex is the primary visual cortex

- visual information is roughly processed in the STRIATE OCCIPITAL CORTEX to start to identify color, form, and movement - lesions to the occipital cortex cause CORTICAL BLINDNESS (the eyes can sense visual data fine but it cannot be processed and perceived; this is a problem with striate cortex but not in other places of the brain) the info is sent to the striate cortex and other parts in the brain

3 main types of sensory receptors

1. PHOTORECEPTORS: convert *light* signals into action potentials - vision 2. CHEMORECEPTORS: convert *chemical* signals into action potentials - smell (long range) and taste (short range sense) 3. MECHANORECEPTORS: convert *mechanical* or physical signals into action potentials - touch and hearing

what is affected by posterior parietal lesions?

APRAXIA: difficulty executing purposeful coordinated movements HEMISPATIAL NEGLECT: neglecting 1 side of body or visual field - effects how they behave (ie, combing only one side of hair on head) DEFECTS IN SPATIAL MEMORY DEFECTS IN VISUAL TRACKING AND ATTENTION ataxia?

brain regions involved in convergent and divergent thinking

CONVERGENT INTELLIGENCE: - activity of the central executive network regions such as the *dlPFC* and *posterior parietal cortex* is increased - damage to these regions greatly decreases convergent intelligence DIVERGENT INTELLIGENCE: - seems to involve switching off (at least temporarily) *the central executive network (and the dlPFC in particular*) and *activating the default mode network* - activity of these regions is increased during improvisation, brainstorming, and flow

neurotransmitter changes in schizophrenia

DECREASED GLUTAMATE: - glutamate antagonists like PCP and ketamine cause both positive and negative symptoms similar to schizophrenia and worsen the symptoms of schizophrenics - glutamate inhibits dopamine release in the striatum and thus a decrease in glutamate would increase dopamine signaling and may explain the positive symptoms of schizophrenia - glutamate in the cortex increases neuronal activation so decreases may explain the negative symptoms of schizophrenia INCREASED DOPAMINE: - dopamine receptor antagonists are effective therapeutic agents for positive symptoms of schizophrenia, while amphetamines, which promote the release of dopamine, can exacerbate positive schizophrenic symptoms - dopamine is involved in motivation and reward and excessive dopamine signaling may facilitate many otherwise undesirable behaviors associated with psychosis and positive symptoms of schizophrenia

behavioral aspects of olfaction

EATING BEHAVIORS - good or bad smelling food may encourage or discourage us from eating - 80% of *flavor* comes from the nose DANGER - fire or predator scent SEX & SOCIAL BEHAVIORS - scent of receptive females, self, kin, strangers of our own species

what are some factors influencing taste?

EMOTIONAL STATE - when we're sad or anxious, food tastes less good - comfort foods - input from AMYGDALA PAST EXPERIENCES - food that have sickened us taste less good - new/strange foods taste less good than familiar ones - input from HIPPOCAMPUS HUNGER - when we are hungry things taste better - input from LATERAL HYPOTHALAMUS OTHER SENSORY INPUTS - *flavor* is the multi -ensory integration of taste, smell, "mouth feel," color, sound, and other sensory inputs - is processed in the *ORBITOFRONTAL CORTEX* (just below eye area of prefrontal cortex) which also integrates flavor with reward pathways - mouth feel, putting everything together flavor is different from taste

factors contributing to ADHD

GENETICS: - up to 75% of ADHD variability may be inherited PRE/PERINATAL FACTORS: - maternal stress during pregnancy or prenatal exposure to tobacco, alcohol and other drugs/environmental toxins, or pregnancy/birth complications--low birth weight/prematurity, neonatal anoxia and seizures, brain injury CHEMICALS IN FOOD/ENVIRONMENT: - lead, polychlorinated biphenyls, food dyes or other additives PSYCHOSOCIAL FACTORS: - high family adversity, high levels of family conflict, inconsistent parenting *for most individuals, it is a combination of genetic susceptibility and environmental factors that probably leads to ADHD*

symptoms of ADHD

INAPPROPRIATE ATTENTIONAL STYLE: - *distributed* attentional style or *hyperfocused* attentional style POOR DECISION MAKING AND IMPULSE CONTROL: - procrastination, disorganized work habits, forgetfulness in daily activities, more risk taking HYPERACTIVITY: - fidgeting, squirming, getting up frequently to walk or run around around, running or climbing excessively, having difficulty playing quietly or engaging in quiet leisure activities EMOTION REGULATION: - greater emotional swings, more tantrums, etc

retinal neurons vs visual transduction

PHOTOREEPTORS: rods and cones BIPOLAR CELLS: link photoreceptors to retinal ganglion cells RETINAL GANGLION CELLS: receive inputs from bipolar and amacrine cells and send information on into the brain HORIZONTAL CELLS also collect information from several photoreceptors and sends it to bipolar cells - receiving convergence from multiple cells AMACRINE CELLS collect information from bipolar cells and send them to several retinal ganglion cells things blur together, pixels on a computer

symptoms of schizophrenia

POSITIVE SYMPTOMS *(PSYCHOSIS):* (added to the behavior) - hallucinations - delusion - paranoia - disorganized thought and speech NEGATIVE SYMPTOMS *(HYPOFRONTALITY):* - blunted emotional responsiveness - social withdrawal - catatonia (complete shutdown) - negative symptoms associated with glutamate negative symptoms refer to symptoms that schizophrenics don't have that non-schizophrenics have or have more of *positive symptoms are more treatable while negative symptoms are not and often have a greater negative impact on quality of life*

rods vs cones

Rods: - larger & cylindrical - more numerous outside fovea - more sensitive, respond to DIM light - responsible for NIGHT VISION and MOTION - only one type of light absorbing pigment Cones: - smaller and tapered at end - less numerous except in fovea - less sensitive, respond to bright light (daylight) - responsible for COLOR, SHAPE, FNE DETAIL - 3 different types of light absorbing pigment rods don't distinguish color some people have a 4th cone can also lack cones

"where" functions of the posterior parietal cortex

SPATIAL NAVIGATION: localization of objects or the body in space PRODUCING PLANNED MOVEMENTS SPATIAL MEMORY: remembering where objects are (repetition, I know what the classroom looks like) VISUAL ATTENTION: being able to follow or track an moving object visually (voluntary saccades)

sensory coding and representation

STIMULUS QUANTITY: the *amount* of a given signal--greater intensity like a brighter light or louder noise is encoded by (1) a greater *discharge rate* or number of action potentials fired by the sensory receptor per unit time, (2) greater number of sensory receptors firing action potentials - how much of it is there STIMULUS QUALITY: the *type* of signal--red vs. green light for example can be coded for by (1) activation of different types of sensory receptors; (2) different *patterns* of action potentials (for sound) - qualitative difference - salty or sweet, cookie smell or monkey poop smell?

5 different tastes

SWEET - surface receptors bind to *glucose* and similar sugars and open a Na+ channel - we like this, it is necessary to survive SALTY - ion channel lets Na+ enter cell - sodium chloride - we like this, it is necessary to survive SOUR - ion channels let H+ ions into cell, which closes a K+ channel - acids - we need some acids - we're not a fan; it is necessary to survive BITTER - binds to a wide range of *aromatic compounds *(has carbon compound), which opens a Na+ channel - we really dislike - bitter is often bad - bitter compounds are often toxic UMAMI - "savory" - binds to the amino acid *glutamate,* which opens a Na+ channel - ex: meaty stuff, i.e. steak FAT?? - maybe 6th taste - may bind to fatty acids we lose taste receptors - neurons can be replaced MSG - saltiness + umami spiciness is a mouth sensation - Capsaicin tricks temperature receptors into thinking it is hot

examples of top-down perceptual processing

Walking up a stopped escalator feels weird and is harder than walking up stairs—why? - because you have a mental construct for escalators and it differs from your mental construct for stairs and since your sensory information does not match your expected model, you have difficulty

the different functions of the ventral and dorsal streams

VENTRAL STREAM & TEMPORAL CORTEX: the "what" path, *object identification* DORSAL STREAM & PARIETAL CORTEX: the "where" path, *spatial location* regions - reflexive circuit

inferior temporal cortex lesions

VISUAL FORM AGNOSIA: inability to recognize objects from their shape - can be specialized like PROSOPAGNOSIA or the inability to identify faces ACHROMATOPSIA: inability to detect ANY colors AKINETOPSIA: inability to perceive movement or moving objects - very rare, only like 6 people have it

hearing volume and pitch

Volume: - a greater number of action potentials in each hair cell burst - a greater number of hair cells producing action potentials Pitch: - a more rapid cycle of action potential bursts per hair cell - *TEMPORAL CODING* - the location of the hair cells activated - *PLACE CODING* higher pitched sounds are sensed by hair cells near the BASE, lower pitched sounds are sensed by hair cells near the APEX how dense and how sparse the bursts are determine how loud the sound is

key point:

each cell in the visual striate cortex receives input from several retinal ganglion cells

key point:

each retinal ganglion cell therefore senses a single *"spot"* of light within the center of its receptive field

key point:

even though axes may be flipped, topographical organization of the visual field is maintained in the neuronal organization of the nervous system

anosmia

loss of sense of smell - humans aren't as reliant on smell like other animals are causes: genetics, some medications, infections, nasal trauma, neurodegenerative diseases (Parkinson's & Alzheimer's), nasal polyps (little tumors), strokes, tumors, TBI, infections affecting the cortical smell centers outcomes: - weight loss (decreased appetite & eating) - danger from gas or smoke or other threatening smells - depression - loss of libido

aguesia

loss of sense of taste - can be temporary or permanent causes: genetics, some medications, vitamin deficiencies (B3, zinc), endocrine disease, neurodegenerative diseases, damage to lingual nerve (oral surgery) or taste buds (smoking, chemotherapy), strokes, tumors, TBI, infections, toxins that affect the cortical taste center outcomes: - weight loss (decreased appetite/eating) - increased risk of consuming something toxic - depression

key point:

once the sensory signal has been converted into action potentials by receptor cells, it must be sent to the central nervous system

key point:

signals can be either *EXTEROCEPTIVE* (originating outside the body; ex: 5 senses), or *INTEROCEPTIVE* (originating inside the body; ex: hunger, satiety, heart rate, breathing) signals made to induce change

similarities and differences between taste and smell

similarities: - both are chemical senses - both use chemoreceptors to convert chemical signals into changes in action potential firing - both are important to flavor - both influence hunger - both communicate directly with key brain receptors such as the hypothalamus and the amygdala to generate emotional responses - both allow us to sense danger - smell from danger and predators and fire, taste from toxic substances differences: - taste is a short range, smell is long range - we have only a small number of taste receptors but over 400 smell receptors - smell is important for sex/reproduction, taste is not - we are born with substrate for taste, liking sweet and disliking bitter, but smell is entirely learned

supertasters vs nontasters

supertasters hate bitter things (ie coffee, red wine, dark leafy greens) - they like food less and are less likely to be overweight nontasters like bitter things

sensory transduction

the conversion of external and internal signals or stimuli into patterns of action potential firing by specialized neurons called sensory receptors turning a smell/sight/etc into an action potential

sensation

the registration of physical stimuli from the environment by sensory receptors - passive act

perception

the subjective experience of sensation

bipolar cells

their firing of action potentials is INCREASED when glutamate levels DECREASE - glutamate: inhibitory, IPSPs