Chapter 3

Question 1

more technical definition of acuity

Answer 1

smallest spatial detail that can be resolved

Question 2

three ways to test acuity

Answer 2

minimum visible (absolute threshold)
minimum resolvable (stripes)
minimum recognizable (snellen test)
minimum discriminable (JND)

Question 3

Snellen Eye Chart

Answer 3

eye doctor chart, show letters (or orientations of letters for universal use)

operationalized visual acuity based on distance relative to “average” people

20/20 - average
20/15 - above average (you can read from 20 ft away what others read at 15 ft)
20/30 - below average

Question 4

acuity tests the size of _____ ______ at which you can identify a _____ in a striped grating

Answer 4

visual angle; cycle

Question 5

cycle of acuity

Answer 5

one full rotation from black to white

Question 6

sine wave grating

Answer 6

gradation between colors

Question 7

smallest angle you can see shift in light = _____

Answer 7

acuity

Question 8

why does an oriented grating appear to be gray if you are far enough away?

Answer 8

your cones are picking up both light and dark luminance, combining them to make gray due to a smaller cycle/frequency

this is because our photoreceptor responses are graded, so some light and some dark = medium

Question 9

two factors that affect acuity

Answer 9

spatial frequency
- visual angle of a change from light to dark (cycle)
- aka the rate at which the luminance changes

contrast
- the amount of difference between a change in luminance
- aka the sharpness of that change in luminance

Question 10

Contrast sensitivity function (CSF)

Answer 10

chart contrast and frequency and see where cycles become invisible on that spectrum

Question 11

CSF can be _____, impacted by changes in _____ ________ and ___ _____

Answer 11

shifted; overall luminance and temporal frequency

Question 12

temporal frequency

Answer 12

how fast the cycle moves

the faster the cycles go, the less acuity you have

Question 13

gabor patches

Answer 13

grading adjusting spatial frequency and contrast

squares with a circle of vision in the middle which is impacted by spatial frequency and contrast

Question 14

how do we measure ganglion activity?

Answer 14

rate of action potential

Question 15

really low and high frequency yields ___ response for action potential, while medium frequency yields ____ response

Answer 15

weak; strong

Question 16

phase

Answer 16

portion of sine wave

Question 17

leaving the eye tract

Answer 17

optic nerve
optic chiasm
optic tract to LGN

Question 18

thalamus

Answer 18

primary relay center of the brain

inhibited when you sleep, lowering your responses to most external stimuli

Question 19

at the optic chiasm, vision is divided by ___ ____, not by ____

Answer 19

visual field; eye

Question 20

at the optic chiasm, regardless of eye;

information for the left side of space goes _____
information for the right side of space goes ____

visual fields represented ____________

Answer 20

right; left; contralaterally

Question 21

how many layers in the LGN

Answer 21

6

Question 22

each side of the LGN receives input from _______ and _________ eye, meaning …

Answer 22

ipsilateral - same eye
contralateral - opposite eye

Question 23

LGN layers 1, 4, 6 receive ______ eye input

Answer 23

contralateral

Question 24

LGN layers 2, 3, 5 receive ______ eye input

Answer 24

ipsilateral

Question 25

the inner two layers of the LGN are the ___________ layer

Answer 25

magnocellular (what M ganglion cells are named after), receiving info from periphery

Question 26

outer two layers of the LGN are the ________ layer

Answer 26

parvocellular (what P ganglion cells are named after), receiving info from fovea

Question 27

why do parvocellular layers in the LGN get more representation?

Answer 27

because they are receiving information from fovea which means more cells report to it

Question 28

Retinotopic Map

Answer 28

map of what is hitting your retina

Question 29

if one eye or one optic nerve is damaged, what is affected?

Answer 29

vision is lost only on the affected side

Question 30

if the optic chiasm is damaged, what is affected?

Answer 30

the outer part of the visual field in both eyes is lost

Question 31

if the visual pathways from the optic chiasm to the visual cortex are damaged, what is affected?

Answer 31

one side of the visual field is lost in both eye ex) damage on the right side of the brain causes loss of the left visual field in both eyes

Question 32

which factors influence our ability to perceive a cycle between black and white? 1) spatial frequency 2) overall luminance 3) contrast 4) all of the above

Answer 32

4

Question 33

Dr. Rafay is an eye doctor. A patient comes to him complaining that they cannot see the right side of their visual space. Their eyes aren’t damaged at all though. What might be wrong with Dr. Rafay’s patient? a) They have damage to their left optic nerve before the optic chiasm b) They have damage to their left optic tract after the optic chiasm c) They have damage to their right optic nerve before the optic chiasm d) They have damage to their optic chiasm

Answer 33

B

Question 34

which layer(s) of the LGN receives input from M ganglion cells of the ipsilateral eye? a) 1 b) 2 c) 3 and 5 d) 4 and 6

Answer 34

B

Question 35

what is the saying to remember what layers of the LGN are contralateral or ipsilateral?

Answer 35

seasick 1 - C 2 - I 3 - I 4 - C 5 - I 6 - C

Question 36

striate cortex

Answer 36

aka primary visual cortex or V1 part of the occiptial lobe of your brain receives bottom-up inputs from the LGN maintains a retinotopic map

Question 37

bottom-up

Answer 37

info from sensory system up into the brain

Question 38

first part of cortex to receive visual input

Answer 38

v1/primary visual cortex

Question 39

how many layers is in the striate/cellular layer

Answer 39

6 but DO NOT correspond to LGN layers

Question 40

fovea is represented at the _____ of the retinotopic map for the striate cortex VF is then represented extending out based on ________ from the fovea

Answer 40

back; eccentricity

Question 41

eccentricity

Answer 41

distance from fovea, measured in degrees of VF

Question 42

what three features are shown in the retinotopic map for the striate complex

Answer 42

contralateral VF (like LGN) inverted from reality cortical magnification of fovea

Question 43

cortical magnification

Answer 43

dramatic scaling of information from different parts of visual fields proportionally more cortex devoted to fovea than periphery, causing loss of acuity susceptible to visual crowding

Question 44

visual crowding

Answer 44

stimuli are harder to perceive because there are other stimuli around than compared to when they are in isolation ex) being able to see a key on the left side (since it is the only item there) but not on the right side (since it is surrounded by multiple items) when staring at a red dot in the center of the image

Question 45

v1 cells respond better to _________ rather than cicular/center-surround like the LGN

Answer 45

lines/bars

Question 46

what can V1 cells code for (depending on LGN cells that feed input)?

Answer 46

any orientation edges vs. bars gratings of various frequencies motion direction

Question 47

simple cells in V1

Answer 47

respond to specific orientation and location

Question 48

complex cells in V1

Answer 48

respond to specific orientation unlike simple, respond to any location

Question 49

end stopping cells in V1

Answer 49

respond to orientation, location and length

Question 50

cortical neurons tend to have a _____ eye, called ______ ________

Answer 50

preferred; ocular dominance V1 cells have an eye they prefer, but will still receive information from both eyes

Question 51

cells in the V1 are grouped in ________

Answer 51

columns line of cells the run perpendicular to the surface of the brain

Question 52

orientation columns in the V1 reflect sets of cells that all respond to ... each column is then ...

Answer 52

the same line orientation; adjacent to columns that are of slightly shifted angle

Question 53

ocular dominance organization

Answer 53

also columnar, but overlaps with orientation columns to form hypercolumns

Question 54

hypercolumns

Answer 54

represent all possible orientations across both eyes for a given part of the visual field since all orientations represent .5 mm and each eye represents .5mm, a hypercolumn is 1 mm

Question 55

inside each hypercolumn are _________

Answer 55

CO blobs full role unclear, part tied to color

Question 56

adaption in columns of striate cortex

Answer 56

cells/columns are tuned for specific things (orientation, location, etc.) but they do not fire forever to that sustained stimulus response is reduced due to sustained/prior exposure to stimulus

Question 57

selective adaption

Answer 57

when **you** can downregulate responding to a specific stimulus by sustaining it

Question 58

due to selective adaption: after staring at lines slanted to the left for 30 seconds, if you look at straight lines they will appear ... why?

Answer 58

slanted to the right due to your cells becoming adapted to them

Question 59

selective adaption effects for _____ and ___________

Answer 59

orientation; spatial frequency

Question 60

high spatial frequency = ________ low spatial frequency = _________

Answer 60

edges are defined; shadows are defined

Question 61

How is the retinotopic map of V1 organized relative to the image on the fovea? a. The fovea is at the back of V1, and the retinotopic map stretches forward based on eccentricity b. The fovea is at the front of V1, and the retinotopic map stretches backwards based on accommodation c. The fovea is at the back of V1, and the retinotopic map stretches forward based on accommodation d. The fovea is at the front of V1, and the retinotopic map stretches backwards based on eccentricity

Answer 61

a

Question 62

We know bars of light can activate V1 **Simple Cells**. Which factor CANNOT influence Simple Cell firing? a. Orientation of Bar of Light b. Position of Bar of Light c. Length of Bar of Light d. Extended duration of Bar of Light e. All of these factors can influence Simple Cell firing rate

Answer 62

e

Question 63

Which statement the organization of columns for a given hypercolumns in V1 is TRUE? a. Each hypercolumn contains all orientations, but with ocular dominance divided across layers b. Each hypercolumn contains all orientations, organized based on ocular dominance c. Each hypercolumn is coded so that columns of a given orientation are always adjacent to their opposite eye column d. Each hypercolumn is coded based on color, organized based on ocular dominance

Answer 63

b