Psych 454 Exam 2 (UW-Madison ; Saalman)

part of the retina that receives light from the center of the visual field

fovea

most sensitive part of the retina

fovea

part of the retina where axons from ganglion cells leave the retina here to form the optic nerve; no photoreceptors here

optic disk (blind spot)

only cell in the retina that fires action potentials

ganglion cells

parts of retina that release neurotransmitter proportional to their level of depolarization (a graded response)

photoreceptors and bipolar cells

2 types of photoreceptors

rods and cones

photoreceptor that enables vision in low-light conditions

rods

photoreceptor that enables high-acuity and color vision in good lighting conditions

cones

where is the highest density of cones?

fovea

where is the highest density of rods?

retinal periphery

in what conditions do sodium channels open?

dark

in what conditions do sodium channels close?

light

when are photoreceptors depolarized?

in dark

when do photoreceptors release glutamate?

in dark

when do photoreceptors hyperpolarize?

in light

when do photoreceptors inhibit glutamate release?

in light

enables contrast sensitivity and edge detection

center-surround receptive fields

cell that receives direct input from photoreceptors

bipolar cells

bipolar cells that respond well to light in the center of the receptive field (not in the surround)

ON-center

bipolar cells that respond well to light in the surround of the receptive field (not in the center)

OFF-center

cells that provide output from retina

ganglion cells

2 main types of receptive fields

ON-center and OFF-center

ganglion cell that responds with either a) the onset of small bright light in center of receptive field or b) the onset of annulus of light in surround of receptive field

ON-center

what are ganglion cells sensitive to?

contrast (adjacent light and dark areas)

3 types of cones

short (blue), medium (green), long (red)

what color corresponds to short wavelength cones?

blue

what color corresponds to medium wavelength cones?

green

what color corresponds to long wavelength cones?

red

theory that states there are 3 cone types at each point on the retina, white = all 3 cones active, colors from different combinations

trichromacy

theory that states that red and green are opponent colors and blue and yellow are opponent colors

color-opponency

what are the 3 channels that carry info from retina to V1?

2 chromatic channels and 1 luminance channel

3 types of ganglion cells

parasol, midget, small bistratified

which ganglion cell contributes to luminance channel?

parasol

which ganglion cell contributes to red-green channel?

midget

which ganglion cell contributes to blue-yellow channel?

small bistratified

in what layers of the LGN are magnocellular neurons in?

1-2

in what layers are parvocellular neurons in?

3-6

in what layers are koniocellular neurons in?

K1-K6

what color cells are in parvocellular layers?

red/green

what color cells are in koniocellular layers?

blue/yellow

what color cells are in magnocellular layers?

black/white

ganglion cell that processes form and color info

parvocellular

ganglion cell that processes color info

koniocellular

ganglion cell that processes motion and depth info

magnocellular

what layers in V1 do magnocellular neuron pathways project to?

sublayer 4Cα

what layers in V1 do parvocellular pathways project to?

sublayer 4Cβ

what layers do koniocellular pathways project to?

layers 1-3

cell that has distinct ON and OFF regions (yields orientation selectivity)

simple cell

cell that has no distinct ON and OFF regions

complex cell

high amounts of cytochrome oxidase that occur at regular intervals in V1; are thought to contribute to color processing

blobs

what are higher-order visual cortical cells selective for?

complex objects or motion direction

audible sound range

0-120 db

rapid pressure fluctuations in a medium

sound

measures the magnitude of pressure fluctuations

sound pressure level

human hearing range

20-20,000 Hz

sound travel speed

340 m/s

3 main cues to localize sound

interaural time difference, interaural level difference, head-related transfer function

difference in time taken for a sound to reach each ear, binaural cue

interaural time difference (ITD)

difference between the sound pressure level at each ear, binaural cue

interaural level difference (ILD)

pinna, head and torso influence the sound before it reaches the inner ear, spectral cue

head-related transfer function (HRTF)

when do we mainly use ITD?

low sound frequencies

when do we mainly use ILD?

high sound frequencies

what are ITD and ILD mainly useful as?

horizontal location cues

sound moves:

tympanic membrane

ossicles move with:

tympanic membrane

malleus, incus, stapes

ossicles

ossicles move:

oval window

how do ossicles act as an amplifier?

convert air movement into cochlear fluid movement

parts of inner ear

cochlear fluids, basilar membrane, inner hair cells, outer hair cells

low K+ cochlear fluid in scala tympani and scala vestibuli

perilymph

high K+ cochlear fluid in scala media

endolymph

what part of the inner ear moves up and down with sound?

basilar membrane

what part of the inner ear transmits info to the brain?

inner hair cells

what part of the inner ear amplifies movement of basilar membrane?

outer hair cells

where is the maximal movement of the cochlear membrane?

at the base for high-frequency sounds and at the apex for low-frequency sounds

when do hair cells depolarize?

when stereocilia deflect towards kinocilium

when do hair cells hyperpolarize?

when stereocilia deflect away from kinocilium

how does the cochlea send info?

via auditory nerve

neurons fire action potentials at a particular phase of the sound wave

phase-locking

when does phase-locking occur?

at low frequencies (<4 kHz)

how is the auditory nerve arranged?

tonotopically (carries info to cochlear nucleus)

what is the first site to receive input from both ears?

superior olive

relays info to olive, preserves response timing of auditory nerve

ventral cochlear nucleus

complex spectral analysis, projects directly to inferior colliculus

dorsal cochlear nucleus

integrates spatial and spectral analysis

inferior colliculus

earliest area sensitive to binaural cues

superior olive

where are ITDs encoded?

medial superior olive

where are ILDs encoded?

lateral superior olive

occupies dorsal and lateral superior temporal gyrus

auditory cortex

auditory cortex regions

core, belt, parabelt

region that includes primary auditory cortex

core

region that surrounds the core region, particularly anterolaterally

belt

region that is posterolateral superior temporal gyrus

parabelt

3 areas of auditory cortex core

primary auditory cortex, rostral field, rostrotemporal field

what sounds does the core respond to?

pure tones

what sounds does the belt respond to?

band-passed noise

what sounds does the parabelt respond to?

complex sounds

what does the auditory ventral "what" pathway process?

auditory objects

what does the auditory dorsal "where/how" pathway process?

sound location

what does the posterior superior temporal gyrus represent?

fast varying speech sounds