Chapter 6 - Vision

Question 1

law of specific nerve energies

Answer 1

Muller’s idea that nerves specialized in one kind of energy (such as vision, audition, etc)

Question 2

light from the left side of the world strikes which half of the retina?

Answer 2

the right (and vice versa)

Question 3

what is the optic nerve made of?

Answer 3

ganglion cell axons

Question 4

what causes the blind spot?

Answer 4

the point where the optic nerve leaves the eye has no visual receptors

Question 5

what is the fovea specialized for?

Answer 5

acute, detailed vision

Question 6

why is the fovea so good at detail?

Answer 6

each receptor cell connects to only one bipolar cell, which connects to only one ganglion cell, which has direct contact to the brain

Question 7

Midget ganglion cells

Answer 7

the ganglion cells in the fovea. They are small and each responds to a single cone

Question 8

rods

Answer 8

abundant in the periphery, respond to faint light

Question 9

cones

Answer 9

abundant in and near the fovea, useful in bright light, essential for color vision

Question 10

trichromatic theory

Answer 10

theory that color is perceived through the relative rates of response by three kinds of cones, each maximally sensitive to a different set of wavelengths

Question 11

which cones are more abundant?

Answer 11

long and medium wavelength cones are far more abundant than short wavelength cones. this is why it’s harder to see blue

Question 12

opponent process theory

Answer 12

the idea that we perceive color in terms of opposites. (a continuum from red to green, blue to yellow, and white to black)

Question 13

color constancy

Answer 13

ability to recognize colors despite changes in lighting

Question 14

retinex theory

Answer 14

the cortex compares information from various parts of the retina to determine the brightness and color for each area that we see

Question 15

receptive field

Answer 15

area in visual space that excites or inhibits a cell in the visual system

Question 16

three kinds of primate ganglion cells

Answer 16

parvocellular
magnocellular
koniocellular

Question 17

parvocellular neurons

Answer 17

ganglion cells with small somas and small receptive fields, that are mostly in or around the fovea

Question 18

magnocellular neurons

Answer 18

larger cell bodies and larger receptive fields, distributed evenly throughout the retina

Question 19

koniocellular neurons

Answer 19

small somas and small receptive fields, distributed throughout the retina

Question 20

what are parvocellular neurons good for?

Answer 20

detecting details. they respond to color too.

Question 21

what are magnocellular neurons good for?

Answer 21

movement and large overall patterns

Question 22

in humans, where do half of the ganglion axons cross contralaterally?

Answer 22

the optic chiasm

Question 23

what is V1 (primary visual cortex, striate cortex) necessary for?

Answer 23

conscious visual perception

Question 24

simple cell

Answer 24

cell in visual cortex that has a receptor field with fixed excitatory and inhibitory zones

Question 25

complex cells

Answer 25

cells in the visual cortex that respond to a pattern or light in a particular orientation (ex: a vertical line). responds most strongly to moving stimulus

Question 26

hypercomplex (end-stopped) cells

Answer 26

same as complex, but with strong inhibitory zone at one end

Question 27

what do cells within a column of the visual cortex have in common?

Answer 27

they respond best to lines of the same orientation

Question 28

retinal disparity

Answer 28

the difference between what the left and right eyes see

Question 29

strabismus

Answer 29

lazy eye: a condition where the eyes don’t point in the same direction

Question 30

astigmatism

Answer 30

a blurring of lines in one direction caused by asymmetric curvature of the eyes

Question 31

ventral stream

Answer 31

area in the temporal cortex that is specialized for identifying and recognizing objects (the “what” pathway)

Question 32

dorsal stream

Answer 32

area in parietal cortex that helps the motor system locate objects (the “where” pathway)

Question 33

what do cells in the inferior temporal cortex respond to?

Answer 33

identifiable objects

Question 34

visual agnosia

Answer 34

inability to recognize objects

Question 35

propagnosia

Answer 35

inability to recognize faces

Question 36

which brain areas are responsible for recognizing faces?

Answer 36

fusiform gyrus
anterior temproal cortex
prefrontal cortex
occipital cortex

Question 37

which area responds more strongly to faces than anything else?

Answer 37

the fusiform gyrus

Question 38

what do cells in V4 respond to?

Answer 38

perceived color of an object

Question 39

Which two areas specialize in identifying motion?

Answer 39

V5 and area MST (medial superior temporal cortex)

Question 40

what do cells in MT (V5) respond to?

Answer 40

when something moves at a particular speed in a particular direction (also images that imply movement)

Question 41

what do cells in MST respond to?

Answer 41

complex stimuli such as expansion, contraction, and rotation of a visual scene

Question 42

what do MST neurons enable you to do?

Answer 42

distinguish between the result of eye movement and the result of object movement

Question 43

motion blindness

Answer 43

the ability to see objects, but impairment at seeing if they are moving

Question 44

saccades

Answer 44

voluntary eye movements