Exam 2

Question 1

How does the perception of music differ from the perception of speech in terms of their hemispheric lateralization and brain areas involved? Is there any overlap between areas for perceiving (non vocal) music and areas for perceiving speech?

Answer 1

• Both speech and music appear fairly early in development, follow a relatively fixed sequence and take sounds from the immediate environment as their input
• mechanisms in the right cerebral hemisphere including pitch-specialized cortical areas are important for both perception and production of pitch, while the left auditory cortical system is specialized for speech sounds that don’t require the same accuracy in pitch tracking
• While both speech and music incorporate pitch variation, it has particular qualities in music that distinguish from speech - its organization as discrete scales in music while in speech, pitch changes tend to be continuous

Question 2

What are some differences between humans and non-human primates might account for our unique appreciation of music?

Answer 2

• In order to link discrete auditory events so encode and decode meaning, need a working memory system. Monkeys limited in their capacity to retain auditory events in their working memory, while humans can relate once sound to another that come seconds or minutes later
• Musical sounds in the animal kingdom are limited to biologically significant vocalizations and thought to be limited to an adaptive role toward territory defense and mate attraction rather than abstract enjoyment
• When given a choice, non-human primates generally prefer silence over listening to music
• monkeys can distinguish between consonance and dissonance but don’t seem to find consonant sounds more pleasurable
• Connectivity between mesolimbic reward system and frontal regions

Question 3

Both humans and other primates seem to keep track of pitch, why is pitch relevant?

Answer 3

Sensitive to the perceptual quality of pitch. Pitch results from periodicity and has biological significance because almost exclusively produced by vocal tracts of other animals in nature, compared to aperiodic natural sounds like wind or water
Tracking pitch would be useful for species to navigate an acoustic environment
Violations of pitch might activate right inferior frontal gyrus
Parabelt regions assemble pitch into melodies

Question 4

Why does music cause pleasure?

Answer 4

• Reward value for music can be coded by activity level in NAcc whose functional activity with auditory and frontal areas increases as a function of increasing musical reward
• Pleasure in music comes from interactions between cortical loops that enable predictions and expectancies to emerge from sound patterns and subcortical systems responsible for reward and valuation
• Widely believed that pleasure people experience in music is related to emotions induced by that music
• Each time a sequence of sounds is heard, templates are activated to fit the incoming auditory information, which will lead to a series of predictions that will be either confirmed or violated and will determine its reward level to the individual
• Cerebral cortex and the striatum work together to make predictions about potentially rewarding future events and assess the outcome of these predictions

Question 5

what experiments did authors conduct?

Answer 5

• Experiment: had participants select highly pleasurable music and continuously rate their experience of pleasure while listening to it. measured sympathetic nervous system activity (heart rate, respiration rate, skin conductance, body temp). Found a positive correlation between ratings of pleasure and increases in SNS activity occurring simultaneously - link between objectives objective indicators of arousal and subjective feelings of pleasure
• as measure of peak emotional arousal, had participants bring in music that gives them chills. Found that ventral striatum and brain regions associated with emotion were recruited as function of increasing intensity of the chills response, showing that mesolimbic reward system could be recruited by an abstract aesthetic
• Experiment: Compared dopamine release in response to pleasurable versus neutral music, and found that strong emotional responses to music lead to dopamine release in the mesolimbic striatum.
• scanned people with fMRI as they listened to new music. Assessed reward value of each piece of music by giving individuals chance to purchase it in an auction paradigm Found that activity in mesolimbic striatal areas, especially NAcc was most associated with reward value of musical stimuli.

Question 6

What brain areas were activated by chill-inducing music?

Answer 6

• Found that ventral striatum and brain regions associated with emotion were recruited as function of increasing intensity of the chills response, showing that mesolimbic reward system could be recruited by an abstract aesthetic
• Also activity in dorsal striatum during the period immediate preceding the chills - phase of anticipation

Question 7

What brain areas were activated by Highly rated novel music?

Answer 7

• For highly rated novel music - Found that activity in mesolimbic striatal areas, especially NAcc was most associated with reward value of musical stimuli. Also auditory cortices in superior temporal gyrus (STG) showed increased functional interactions with NAcc during processing of musical sequences with high reward value. Also increased connectivity of frontal cortex with NAcc during highly rewarding music processing

Question 8

What does the brain use for energy? How is this different from the rest of the body?

Answer 8

Brain uses glucose for energy, and only glucose. Body can use glucose, protein or triglycerides

Question 9

What is ghrelin?

Answer 9

Ghrelin is a peptide hormone released in the fasting phase and an endocrine signal for hunger. Produced and released by the empty stomach and increases before meals. Binds to receptors in the hypothalamus to help stimulate eating behavior

Question 10

What other types of signals facilitate feeding?

Answer 10

Other metabolic signals that arise in the fasting phase if it persists long enough:
•Lipoprivation
•Glucoprivation
Top-down influences change how brain pays attention to hunger - eg. hearing someone talk about food

Question 11

lipoprivation

Answer 11

depriving cells of lipids, low levels of triglycerides. Liver perceives low triglycerides and concentrations of fat. Liver has receptors that detect low availability of fatty acids and send this info to brain through vagus nerve.

Question 12

glucoprivation

Answer 12

hypoglycemia (fall in blood glucose level) is stimulus for hunger. Brain receives glucoprivic hunger signal from the liver through the vagus nerve. Brain also has signals in the medulla that monitor the availability of nutrient inside BBB

Question 13

what type of information signals mammals to stop eating?

Answer 13

• Short-term satiety signals tell brain you’ve had enough food
• Main signal to stop eating is distention of the stomach - will not feel full until stomach is distended

Question 14

What type of information is carried by the Vagus and splanchnic nerves?

Answer 14

• Splanchnic nerves convey info about nutrient contents of stomach
• Vagus nerve conveys info about the stretching of the stomach walls to the brain

Question 15

what role does duodenum play in stopping a meal?

Answer 15

Duodenum can release CCK hormone to tell brain to stop eating, and distension of duodenum can also produce feelings of satiety
Duodenum is part of the small intestine where initial absorption of significant amounts of nutrients occurs. Controls rate of stomach emptying by secreting peptide hormone CCK

Question 16

What is cholecystokinin?

Answer 16

• A peptide hormone that causes gallbladder to contract which injects bile into the duodenum. Secreted in response to presence of fats and causes pylorus to constrict and inhibit gastric concentrations, which keeps stomach from giving duodenum more food
• Signals from CCK receptors are transmitted to brain through vagus nerve telling brain that duodenum receiving food from the stomach

Question 17

what other chemicals help to terminate eating?

Answer 17

•Peptide YY (PYY) is produced by cells in gastrointestinal tract and released by small intestine in amounts proportional to amount of calories that were just ingested
There are receptors for types of nutrients that are consumed - small intestine can keep track of amount of calories consumed
•Insulin - absorptive phase of metabolism accompanied by increased level of insulin in blood. Insulin permits organs other than brain to metabolize glucose, and promotes entry of nutrients into fat cells. Brain doesn’t need insulin to metabolize glucose but has insulin receptors to detect presence of insulin in the blood, which tells brain body is probably in absorptive phase of metabolism

Question 18

what role does leptin play in feeding behavior?

Answer 18

• Leptin is a peptide hormone that is normally secreted by well-nourished fat cells. Increases metabolic rate and decreases food intake - acts as anti-obesity hormone
• Sent by body to regulate hunger and feeding behavior in long-term. Signals there’s enough energy stored so can stop eating - low levels of leptin will increase hunger

Question 19

What brain regions play roles in feeding behavior?

Answer 19

• Brain stem contains neural circuits that can detect hunger and satiety signals and control at least some aspects of food intake
• Lateral hypothalamus involved in initiating eating, and ventromedial hypothalamus involved in regulating satiety
• arcuate nucleus

Question 20

What types of feeding neurons are observed in the hypothalamic arcuate nucleus?

Answer 20

Neurons sensitive to hunger signals: ghrelin, environmental cues
Neurons sensitive to satiety signals: taste pathways, insulin, CCK, leptin

Question 21

What role does NPY play in feeding?

Answer 21

• A neurotransmitter that is extremely potent stimulator of food intake
• Cell bodies of most neurons that secrete NPY are found in arcuate nucleus
• Glucoprivation and ghrelin activate the orexigenic NPY neurons
• NPY neurons in arcuate nucleus of hypothalamus receive input from glucose-sensitive neurons in the medulla, and they’re the primary target of ghrelin in the hypothalamus

Question 22

What is the difference between sensation and perception?

Answer 22

• Sensation - hierarchical, physiological processes involved with taking in information - Involves the cells of the nervous system that are specialized to detect stimuli from the environment
• Perception - psychological processes involved in organization and interpretation of sensation -Perception is a winner-take-all: once you perceive one thing, your brain inhibits perception of other contrasting things - The conscious experience and interpretation of information from the senses and involves neurons in the CNS

Question 23

What is meant by bottom-up versus top-down processing?

Answer 23

•Bottom-up: from stimulus to neural activity to identification (“physical”), aka “data-driven”
•Top-down: influence from expectations, knowledge and surrounding context on what we sense and perceive (“psychological”), aka “knowledge-driven”
-Taking info from schema, modified by conditions that are already there
•Expectations and attention influences what bottom-up signals are amplified or diminished. Starting point for top-down is perceptual awareness, and this can be directed in different places which influences how you process bottom-up signals

Question 24

Understand the levels of analysis associated with psychophysics, sensory physiology and cognitive neuroscience.

Answer 24

Psychophysics - studies quantitative relationship between stimuli and perception
Sensory physiology looks at the relationship between the stimulus and processing the stimuli
Cognitive neuroscience involves how the processing of stimuli leads to perception of the stimulus

Question 25

absolute versus difference threshold

Answer 25

Absolute threshold - smallest amount of stimulus energy necessary to detect a stimulus
Difference threshold - smallest difference between two stimuli that a person can detect

Question 26

common features of all sensory systems

Answer 26

1) receive a physical stimulus
2) Transduce the physical stimulus into an electrochemical signal
3) Movement of a signal along sensory pathways from periphery to brain
4) Form whole perceptions of objections out of many such signals

Question 27

transduction

Answer 27

stimuli are detected by sensory receptors that alter, through various processes, the membrane potentials of the cells - Being able to translate a sensory cue into electrochemical signal of the brain

Question 28

Understand the general organization of sensory systems.

Answer 28

Each sensory system has a distinct group of pathways and stations in the brain:
•Pathways: nerves (PNS); tracts (CNS)
•Stations: relay ganglia (PNS); relay nuclei (CNS)

Question 29

connections of thalamic nuclei (thalamic nucleus –> input –> output)

Answer 29

• ventral posterior lateral nucleus: input is body, output is primary somatosensory cortex
• ventral posterior medial nucleus: input is head (skin and tongue), output is primary somatosensory cortex
• lateral geniculate nucleus: input is retina, output is primary visual cortex
• medial geniculate nucleus: input is inner ear, output is primary auditory cortex

Question 30

What is meant by the term “accessory structure”? What are some examples?

Answer 30

Parts of the sensory systems that gather external stimulus energies and “create” the proximal stimulus which reaches the sensory receptor cells
Eg. hair, skin, ear, nose, tongue, eye, eyelids, etc.

Question 31

What are the four classes of sensory receptors cells, and what type of information can be carried in each class?

Answer 31

Mechanoreceptors: activated by mechanical energy, mediate touch (pressure energy), proprioception (muscle and joint displacement energy), hearing (sound wave energy), balance (gravity energy), pain
Proprioception - body’s understanding of where your body is in space, knowing how far you have to move your arm before it hits the table
Chemoreceptors: activated by chemical energy, mediate taste, smell and pain
Thermoreceptors: activated by thermal energy, mediate temperature and pain
photoreceptors : activated by electromagnetic energy, mediate vision

Question 32

what is a sensory receptor cell

Answer 32

a specialized neuron or specialized epithelial cell that converts physical energy into changes in membrane potential

Question 33

What sensory receptor cells are derived from neurons vs. epithelial cells?

Answer 33

• Sensory receptor cells for gustation and audition balance are derived from epithelial cells
• Sensory receptor cells for olfaction, vision, touch, pain, temperature, and proprioception are derived from neurons

Question 34

How are receptor potentials similar or different from typical post-synaptic potentials?

Answer 34

• Changes in receptor potentials are similar to a typical post-synaptic potentials in that both are graded and local
• Graded - a stronger signal will produce a larger response. Eg. hand on burner versus out in the sun
• Local - within post-synaptic potential, doesn’t change the voltages of other areas - just within the synapse or the receptor
• They’re different because in receptor potentials, changes are initiated by sensory stimulation rather than by another neuron

Question 35

What is a receptive field? How might receptive fields change as we move through sensory pathways? (i.e. through relay nuclei)

Answer 35

• Receptive field: stimulus region and features that cause maximal response of a cell in a sensory system
• For sensory receptor cells, region tends to be small and simple (just excitatory) - usually presence of sensation and not the absence
• Receptive fields get larger and more complex as you move through the sensory pathway

Question 36

How is stimulus intensity typically coded in sensory systems?

Answer 36

the stronger the sensory stimulus, the:
•Greater the size of the receptor potential in a sensory receptor cell
•Greater the number of activated sensory receptor cells (“population coding”)
•Greater the rate of action potentials in a sensory system

Question 37

What is the difference between slow- and fast-adapting receptors? What kind of information is coded by these different receptors?

Answer 37

Slow-adapting receptors: action potentials to a constant intensity stimulus
•Would keep on firing at elevated rate throughout duration of that stimulus
•Can help with timing and duration of stimulus but not good at detecting changes in the stimulus
Fast-adapting receptors: action potentials to a changing intensity stimulus
•Fire a bunch at beginning of stimulus and adapt by end of stimulus and fire at slower rate
• Good at signaling onset of a stimulus, can see location and change in that stimulus

Question 38

What is a labeled line code? What are examples?

Answer 38

• There is a different type of sensory receptor cell for each sub-modality (Eg. pain vs. light touch, sweet vs. bitter)
• Stimuli are coded by activation of a large number of broadly-tuned sensory receptor cells
• E.g. sound frequency
• Have a pressure sensitive receptor and temperature sensitive - these have sensory pathways into brain and they never cross. Info follows segregated pathway all the way into nervous system

Question 39

What is a patterned code? What is an example?

Answer 39

Stimuli of different sub-modalities activate the same sensory receptor cells but in differing amounts
Representation of stimulus = pattern of activations of different sensory receptor cells
If had receptors but there was convergence and divergence in path - eg. multiple projecting to one cell. Because everything crossing, way neurons fire isn’t determined by one activity, these neurons will fire best when receive certain pattern of stimulation so no one neuron is going to produce something that activates one and only one receptor
Activating any one of cells would produce some foreign weird smell, but at higher levels when info becomes integrated, then might have neuron that is lemon or orange smell specifically

Question 40

Know 6 qualities of taste and what kind of molecules are involved in producing the individual qualities

Answer 40

Umami - amino acids, detects presence of glutamate, ability to taste proteins
Fat - fatty acids, detected by odor and texture
Saltiness - Na+, K+, Li+ and a small anion
Sweetness - sugars, most sweet-tasting foods are safe to eat
Bitterness - plant alkaloids
Sourness - acidic (H+)

Question 41

What taste sub-modalities are transduced by ionotropic receptors? Metabotropic?

Answer 41

Ionotropic receptors: saltiness and sourness

Metabotropic (g-protein coupled): bitterness, sweetness, umami, fat

Question 42

what are taste receptor cells and what do they use as their neurotransmitter

Answer 42

taste receptor cells are epithelial cells that use ATP as their neurotransmitter

Question 43

What cranial nerves carry taste information to the brain and where do they synapse?

Answer 43

Axons convey information to brain through 7th, 9th and 10th cranial nerves (determined by location in tongue)
Taste receptor cells form synapses with dendrites of bipolar neurons (first order neurons)

Question 44

Where is the first relay for taste information? Where does it send its axons in the thalamus? Where within the cerebrum?

Answer 44

First relay for taste information is the nucleus of the solitary tract, locating in the medulla
The taste-sensitive neurons of the nucleus of the solitary tract send their axons to the ventral posteromedial thalamic nucleus
Thalamic taste-sensitive neurons send their axons to the primary gustatory cortex

Question 45

What kinds of molecules stimulate olfactory receptors? What type of receptors are they and where are they located?

Answer 45

Odorants are volatile substances that are lipid soluble and of organic origin
The olfactory receptor cells are bipolar neurons and they reside within 2 patches of mucuous membrane aka the olfactory epithelium (each about 1 square inch). Their cell bodies lie within the olfactory mucosa that lines the cribriform plate

Question 46

What is the role of the supporting cells next to olfactory receptor cells?

Answer 46

Secrete enzymes that destroy odorant molecules which prevents them from damaging the olfactory receptor cells - olfactory molecules have limited time to interact, so you don’t keep smelling gingerbread all the time
Produce the mucus that traps odorant molecules

Question 47

What is an olfactory glomerulus?

Answer 47

Olfactory glomerulus - a bundle of dendrites of mitral cells and the associated terminal buttons of the axons of olfactory receptors

Question 48

What do axons synapsing in any given olfactory glomerulus have in common?

Answer 48

Came from olfactory receptor neurons that have same type of sensory receptor - will send axons to same place and converge on glomerulus

Question 49

What are mitral cells?

Answer 49

Mitral cells are second-order neurons located in the olactory bulb that receive information from the olfactory receptor and whose axons bring information to the rest of the brain through the olfactory tracts

Question 50

What does it mean that odors are transmitted in a population code?

Answer 50

No odorant acts with just one receptor - each odorant can act on a number of receptor
Because a given glomerulus receives info from only one type of receptor, different odorants produce different patterns of activity in different glomeruli
Recognizing a particular odor is a matter of recognizing a particular pattern of activity in the glomeruli

Question 51

What’s the name for the primary olfactory cortex

Answer 51

piriform cortex

Question 52

what other regions in the cerebrum receive olfactory information?

Answer 52

Olfactory tract axons project directly to the amygdala, the piriform cortex and the entorhinal cortex
Amygdala sends information to the hypothalamus, the entorhinal cortex sends it to the hippocampus, and the piriform cortex sends it to the hypothalamus and the orbitofrontal cortex

Question 53

What area of the brain integrates information from smell, taste, and other senses to give us perception of flavor?

Answer 53

Orbitofrontal cortex

Question 54

What is the opponent process of color-representation?

Answer 54

Unlike cones, retinal ganglion cells use an opponent-color system - the neurons respond specifically to pairs of primary colors
The retina contains two kinds of color-sensitive ganglion cells: red-green and yellow-blue
The response characteristics of retinal ganglion cells to light of different wavelengths are determined by the particular circuits that connect the three types of cones with the two types of ganglion cells
An axon that signals red or green can either increase or decrease its rate of firing, and can’t do both at the same time - which explains why we can’t perceive a reddish green or a bluish yellow

Question 55

cones

Answer 55

Approx 6 million cones in the retina, most prevalent in central retina
Found in fovea
Sensitive to moderate to high levels of light - Responsible for daytime vision
Provide information about hue
Provide excellent acuity

Question 56

rods

Answer 56

Approx 120 million rods in the retina, most prevalent in the peripheral retina
Not found in fovea
Sensitive to low levels of light - responsible for vision in dimly-lit environments
Provide only monochromatic information
Provide poor acuity

Question 57

What are the three layers of the retina? What cells are found in each layer? How do they exchange information?

Answer 57

Photoreceptors - rods and cones, don’t produce AP - release of glutamate is regulated by membrane potential
Bipolar cell layer - neurons whose two arms connect the shallowest and deepest layers of the retina, don’t produce AP - release of glutamate is regulated by membrane potential
Ganglion cell layer - neurons whose axons travel through the optic nerves and carry visual information to the rest of the brain, project to structures within the brainstem

Question 58

what nerve do the axons of the retinal ganglion cells make up?

Answer 58

Axons of retinal ganglion cells make up optic nerve

Question 59

What terminology is used to describe various eye movements?

Answer 59

Vergence movements - cooperative movements that keep eyes fixed on the same target (keep image on corresponding parts of the two retinas)
Saccadic movements - shifting gaze from one point to another, how you move your eyes when you have no single target (can’t control speed of movement between stops). Used when scanning scene
Pursuit movement - requires focus on one object, used to maintain image of a moving object on the fovea
Extraocular muscle movements - for maintaining a focused image on both retina

Question 60

Know a few other areas that receive visual information from the retina, besides the LGN

Answer 60

Primary visual cortex aka V1 aka striate cortex

Visual association cortex aka V2 aka extrastriate cortex

Question 61

What kind of information travels to the magnocellular, parvocellular and koniocellular regions of the LGN?

Answer 61

Magnocellular - inner two layers
Output goes to sublayer 4Cα in striate cortex
Perception of form, movement, depth and small differences in brightness
Parvocellular - outer four layers containing smaller cell bodies
Receive information about wavelength from red and green cones, provide info concerning color
Perception of color and fine details to the primary visual cortex
Output goes to sublayer 4Cβ in striate cortex
Koniocellular sublayers - found below other layers
Receive information about wavelength from blue cones, provide info concerning color
Transmits information from blue cones to primary visual cortex
Output goes to sublayers 2 and 3 in striate cortex

Question 62

What is meant by high-frequency vs. low frequency visual information?

Answer 62

Spatial frequency is variation in brightness measures in cycles per degrees of visual angle, density of the information
High-frequency: small objects, details within a large object, large objects with sharp edges, can be erased by distance (lincoln pictures)
Low-frequency: large areas of light and dark

Question 63

Why is V1 called striate cortex? Where is it located?

Answer 63

It contains a dark-staining layer (striation) of cells

Located in the occipital lobe

Question 64

What type of visual features are represented by cells in V1?

Answer 64

Orientation sensitivity and movement - cell will only respond to edge or line when it’s in a particular position/orientation
Spatial frequency
Retinal disparity - perception of depth
Color

Question 65

What types of features are represented in blobs? Non-blob regions in V1?

Answer 65

Neurons in CO blobs project to thin stripes - color

Neurons outside the blobs project to pale stripes - orientation and spatial frequency

Question 66

What are thin, thick, and pale stripes in V2 and how do they connect to V1 and the what and where/how pathways?

Answer 66

•Visual processing in V2 divides into the dorsal stream and the ventral stream
-Ventral stream begins with neurons in the pale and thin stripes in V2 and projects to subareas of inferior temporal cortex
-Dorsal stream begins with neurons in thick stripes of V2 and ascends into regions of posterior parietal cortex
•Ventral stream recognizes what - what an object is, what colors it has, provides visual info about size, shape, color and texture of objects and other people
•Dorsal stream recognizes where/how - where the object is located and if it’s moving, the speed and direction of movement. Provides visual info that guides navigation and skilled movements directed towards objects, involved in visual control of movements

Question 67

What areas are involved in the “What pathway”

Answer 67

Ventral stream: V2 → V4 → inferior temporal cortex

Question 68

What is achromatopsia? What areas are involved?

Answer 68

Life becomes black and white, colors can’t even be imagined

Damage in V8

Question 69

What is the FFA? What does it recognize? What does damage here cause, and what is the name for this condition? What evidence is there that the FFA might need to incorporate the word “flexible” into its name?

Answer 69

Prospoagnosia - inability to recognize faces
Evidence from experiment involving “greebles” - learned to recognize “gender” and “family” or greebles even though they don’t really have a face

Question 70

What is the EBA?

Answer 70

EBA - extrastriate body area specifically activated by photographs, silhouettes, or stick drawings of human bodies or body parts, but not by control stimuli such as photographs or drawings of tools, scrambles silhouettes or stick drawings
Recognizes body parts, headless bodies, but not objects or faces

Question 71

PPA

Answer 71

parahippocampal place area - located in region of limbic cortex, borders hippocampus, and activated by sight of scenes and backgrounds

Question 72

Why is the “Where” pathway also referred to as the “How pathway?” What areas are involved?

Answer 72

If you suffer injury that damages dorsal stream - main deficit would be how you interact with things in your environment (grasping, etc.)
The visual cortex of the posterior parietal lobe is extensively connected to regions of the frontal lobe involved in controlling eye movements, reaching movements of the limbs, and grasping movements of the hands and finger

Question 73

How does area MT or V5 involved contribute to perception?

Answer 73

V5 or area medial temporal has neurons that respond to complex patterns of movement
Important function of area MT and medial superior temporal is analysis of optic flow - the relative movement of the visual elements of your environment

Question 74

What is akinetopsia

Answer 74

Bilateral damage to brain that includes V5 produces inability to perceive movement - akinotopsia
Individuals experience a series of still images that appear to refresh periodically

Question 75

Know what physical qualities of sound are represented in the perceptions of pitch, loudness and timbre

Answer 75

Frequency - number of compressed or rarified patches of air that pass through our ear (hertz)
Amplitude - difference in pressure between compressed and rarified patches (decibels)
Complexity - sounds are a mixture of frequencies and amplitudes

Question 76

Know about the structure of the Organ of Corti

Answer 76

The receptive organ that consists of the basilar membrane, the hair cells and the tectorial membrane

Question 77

What is accomplished by inner and outer hair cells

Answer 77

Inner hair cells responsible for auditory perception

Outer hair cells responsible for amplifying and tuning the organ of corti

Question 78

know about how cilia and ion channels transduce sound waves into glutamate release and the importance of potassium concentrations.

Answer 78

Bending of bundle of cilia causes receptor potentials by influx of K+
When bundle moves toward the tallest cilium, the increased tension on tip links opens all the ion channels and the flow of cations into the cilia increases, and the membrane depolarizes

Question 79

What features are used to determine the localization of sound horizontally? Vertically?

Answer 79

Horizontally - binaural cues based on comparison of sound reaching left and right ears
Vertically - monaural cues based on sound to one ear which is first reflected from head and also back and forth within various fold of pinnae

Question 80

how sound is localized at the level of the medial and lateral superior olive

Answer 80

Neurons that detect binaural differences in phase or arrival time are located in medial superior olivary complex -interaural time difference - difference between times that sound reaches ears
Neurons that detect binaural differences in loudness are located in the lateral superior olivary complex - interaural level difference - difference in sound pressure level of sound reaching left and right ears

Question 81

Know the location of the primary auditory cortex and the different streams of information processing that originate there

Answer 81

Primary auditory cortex lies hidden on upper bank of lateral fissure
Two streams:
Anterior stream is involved with analysis of complex sounds
Posterior stream involved with sound localization

Question 82

What are some cues that lead to the perceptions of complex sounds in the environment as individual auditory streams?

Answer 82

Location 
Similarity of timbre and pitch 
Proximity in time 
Good continuation 
Experience