The Visual System Flashcards

See what you can see

1
Q

light entering the retina moves at

A

300,000km/hr

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2
Q

we can see electromagnetic energy between

A

380 and 760 nanometers in length

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3
Q

wavelength relates to

A

role in colour perpception

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4
Q

intensity relates to

A

perception of brightness

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5
Q

our pupil dilation is a compromise btw

A

sensitivity and acuity

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6
Q

behind the pupil is the

A

lens

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7
Q

the lens does what?

A

focuses incoming light on the retina

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8
Q

tension on the lens is adjusted by

A

the ciliary muscles

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9
Q

accommodation is done by

A

the lens adjusting to focus

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10
Q

turning eyes slightly in

A

convergence

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11
Q

the diff in position of the same image on the two retinas

A

binocular disparity

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12
Q

Binocular disparity is greater when things are

A

closer

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13
Q

first 3 steps of light entering the eye

A

pupil
lens
retina

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14
Q

what does the retina do?

A

converts light to neural signals, conducts to the CNS, helps process signals

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15
Q

name the 6 types of retinal cells or I’ll burn your house down

IN ORDER!!!

A

Rods
Cones
Horizontal
Bipolar
Amacrine
Retinal Ganglion

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16
Q

axons that project outside the eyeball and end in bundle

A

Retinal ganglion

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17
Q

what is the center of the retina

A

the fovea

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18
Q

how does the visual system fill in the retinal gaps?

A

completion

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19
Q

Cones are good for

A

colour, good light, high acuity

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20
Q

Rods are good at

A

low light

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21
Q

rods are ___receptors,

A

scotopic

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22
Q

cones are ___ receptors

A

photopic

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23
Q

cones have hundreds of outputs that converge on a single RGC

T or F?

A

FALSE

Suuuuper false

so false

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24
Q

the fovea only has

A

cones

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25
Q

what happens at the edge of the fovea?

A

cones drop off, rods increase

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26
Q

cones can’t see colour, TF????

A

Falllseeee

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27
Q

in the Purkinge effect…

A

low light- blues seem brighter

high light red and yellow seem brighter

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28
Q

light to neural signal is

A

visual transduction

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29
Q

a red pigment that lose it’s ability to absorb in intense light

A

Rhodopsin

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30
Q

our sensitivity to various wavelengths is due to

A

Rhodopsin’s ability to absorb them

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31
Q

When Rhodopsin molecules are indarkness their ___are partially open

A

sodium channels

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32
Q

signals in the Retina-geniculate-striate system reach both sides of of the visual cortex

A

ipsilaterally and contralaterally

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33
Q

Retina-geniculate-striate is organized

A

retinotopically

34
Q

there are ___ pathways from the eyes to the cortex

A

4

35
Q

the nasal hemiretinas cross over at the

A

optic chiasm

36
Q

the temporal hemiretinas cross over at the ?

A

THEY DO NOT CROSS OVER!! Trick question

they are ipsalateral motherfucker!!

37
Q

Parvocellular layers are__ and are for

A

small cell body neurons and are for colour, fine pattern, slow, still objects

38
Q

Magnocelluar layers are __ and are for__

A

large cell body neurons, for movement

39
Q

cones go to which channel in the lateral gen?

A

Parvocellular!

40
Q

Rods go to which channel in the lateral gen?

A

Magnocelluar

41
Q

Bipolar cells get their edge info from

A

cones

42
Q

bipolar cells enhance

A

center vision

43
Q

Neural signals are carried from the retina to the lateral geniculate nuclei by

A

the axons of RGCs

44
Q

photopigment of rods is

A

rhodopsin

45
Q

non-existent stripes running at the edges, make edges easier to see

A

mach bands

46
Q

how did Hubel and Weiss map receptive fields?

A

microeletrode near single vis system neuron

eye moves blocked with paralytic

images on screen focused on retina

record repsonses of Neuron to various simple stims

47
Q

when an achromatic light was shone onto the receptive fields of the RGS pathway

A

on off firing depending on location in field

based on off center or on center

48
Q

on center cells in the retinal-geniculate-striate respond to

A

light in central vision field with ON firing and lightst in the peripheral with inhibition

49
Q

simple striate cells respond best to

A

straight line borders, bars of light,

50
Q

complex striate cells respond best to

A

stim to both eyes, retinal disparity,

51
Q

the primary vis cortex is organized into

A

vertical right angles to the cortical layers

52
Q

each vertical column of the PVC reps to

A

stim on the same retinal area, same eye

53
Q
  • the complexity of the preference of cortical cells progresses from the
A

retina, to thalamus to the lower IV levecl of the PVC

54
Q

PVC neurons resp to

A

texture
line orientation
line movement
periodic patterns
spatial gradients

55
Q

3 types of colour receps (cones), each with diff spectral sensitivity, colour is encoded by ratio of activity in the 3 types of cones

A

trichromatic

56
Q

two classes of cells in vis system

Brightness and colour

A

opponent process

57
Q

in opponent process red is green as blue is

A

yellow

58
Q

the colour vision in most primates is

A

trichromatic

59
Q

the fact that perceived colour of an object is not a simple function of the reflected wavelengths

A

colour constancy

60
Q

the colour of an object is determined by it’s reflectance- the ratios of light of diff wavelengths it reflects on it’s surface

A

Retinx theory

61
Q

the PVC gets most of it’s input from

A

the lateral geniculate nuclei (in the thalamus)

62
Q

the PVC is mostly hidden by the

A

longitudinal fissure

63
Q

the 2ndary PVC is mostly in the

A

prestriate cortex (band around the PVC)

64
Q

the biggest association cortex for vis is in the

A

posterior parietal cortex

65
Q

the order of the vis cortexes is

A

PVC- 2ndary, association

66
Q

area of blindness in corresponding contralateral visual field of both eyes

A

Scotoma

67
Q

the dorsal stream runs from the

A

PVC- Dorsal prestriate-posterior parietal cortex

68
Q

the dorsal stream resp strongly to

A

WHERE??? location and time

69
Q

the ventral stream runs from

A

PVC- ventral prestriate- inferotemporal cortex

70
Q

Ventral stream responds strongly to

A

WHAT???
colour and shape

71
Q

clusters of vis neurons with classes for objects, face, animals are in the

A

ventral stream

72
Q

dorsal mediates

A

interaction

73
Q

ventral stream directs

A

conscious perception

74
Q

visual agnosia for faces (dev or acquired)

A

Prosopagnosia

75
Q

failure to recognize faces is

A

Agnosia

76
Q

what causes issues with facial recognition?

A

damage to the fusiform gyrus

77
Q
  • can’t see moving objects smoothly
A

Akinetopsia

78
Q

Complexity
Hierarchy
Parallel Processing
Functional Segregation/specialization

are the

A

principles of visual system organization

79
Q

principles of visual system organization

A

Complexity
Hierarchy
Parallel Processing
Functional Segregation/specialization

80
Q

patching the good eye after corrective surgery is for treatment of

A

amblyopia

81
Q
A