chapter 3

Question 1

refraction

Answer 1

the phenomenon whereby light changes direction (bands) as it passes from one medium to another

Question 2

optical lense

Answer 2

device that focuses light via refraction

Question 3

wedge prism goggles

Answer 3

special type of goggles that distorts the retinal image

Question 4

prism adaptation

Answer 4

when participants wear prism goggles, they learn to adapt their motor movements to accommodate the distorted image, revealing how adaptive the visual system can be

Question 5

how do we measure the retinal image size?

Answer 5

trigonometry

Question 6

principles of visual angles

Answer 6

• if we hold viewing distance constant, shrinking an object will shrink the visual angle
• if we move an object closer to the eye, the visual angle will increase

Question 7

accommodation

Answer 7

the process by which the eye changes its focus by bending the lens

Question 8

refractive error

Answer 8

disorder in which the image of the world is not properly focused on the retina, resulting in the retinal image being blurry and out of focus

Question 9

causes of refractive errors

Answer 9

myopia
hyperopia
presbyopia
astigmatism

Question 10

myopia

Answer 10

near sighted

eyeball is elongated in depth and the focal point falls short of the retina, resulting in far objects appearing blurry

Question 11

hyperopia

Answer 11

far sighted

eyeball is shortened in depth and the focal point falls beyond the retina, resulting in close objects appearing blurry

Question 12

presbyopia

Answer 12

old sight

lens becomes less flexible with age, resulting in close and far objects being blurry

Question 13

astigmatism

Answer 13

cornea is misshaped, causing light to be retracted in an abnormal manner, leading to multiple focal points. this results in blurry images at every distance

Question 14

color blindness

Answer 14

some people are born without certain types of photoreceptors, resulting in certain colors that are easily identifiable to most being unidentifiable to them

Question 15

dichromats

Answer 15

2 out of 3 cones necessary to perceive color, making some colors hard to discriminate

cones S M L missing

Question 16

monochromats

Answer 16

see everything in shades of grey

Question 17

ishihara test

Answer 17

color discrimination test in order to report a number value

Question 18

how does the eye process light?

Answer 18

before it leaves the eye

Question 19

midget bipolar cell

Answer 19

received input from a single photoreceptor and is primarily found in central vision

Question 20

diffuse bipolar cell

Answer 20

receives input from multiple photoreceptors and is primarily found in peripheral vision

Question 21

on cells

Answer 21

increase firing rates in response to a photoreceptor sensing light

Question 22

off cells

Answer 22

decrease firing rates in response to a photoreceptor sensing light

Question 23

on center

Answer 23

excitatory center and inhibitory surround

Question 24

ganglion cells

Answer 24

each cell is connected to several bipolar cells

Question 25

off center

Answer 25

inhibitory center and excitatory surround

Question 26

receptive field

Answer 26

the region on the retina in which visual stimuli influence a neuron’s firing rate

Question 27

p ganglion cell

Answer 27

receives input from a single midget bipolar cell in the central retina, outputting to the parvocellular system

Question 28

m ganglion cell

Answer 28

receives input from multiple diffuse bipolar cells in peripheral vision, outputting to the magnocellular system

Question 29

spatial frequencies

Answer 29

the number of grating cycles in a given unit of space

Question 30

what is the general rule for ganglion cells?

Answer 30

the higher the contrast the more a retinal ganglion cell will fire

Question 31

lateral geniculate nucleus

Answer 31

relay station that copies information onward to the visual cortex. it preserves left vs right information

Question 32

magnocellular

Answer 32

two layers of large cells that encode large moving objects

Question 33

parvocellular

Answer 33

four layers of small cells that encode details of stationary objects

Question 34

left v1

Answer 34

represents the right visual hemifield

Question 35

right v1

Answer 35

represents the left visual hemifield

Question 36

cortical magnification

Answer 36

the center of the visual field has more v1 neurons representing it than the periphery of the visual field

Question 37

retinotopic organization

Answer 37

v1 cortex is organized so that spatial information from the retina is retained

Question 38

primary visual cortex v1

Answer 38

the neurons in the primary visual cortex accumulate information across several retinal ganglion cells which allows them to detect simple visual features