4.2 The visual system

Question 1

Sclera

Answer 1

1 White outer surface of eye

Question 2

Cornea

Answer 2

2 the clear layer that covers the front portion of the eye - focus

Question 3

Pupil

Answer 3

3 regulates the amount of light that enters by changing its size

Question 4

Iris

Answer 4

4 a round muscle that adjusts the size of the pupil - colour

Question 5

Lens

Answer 5

5 a clear structure that focuses light onto the back of the eye (accommodation - change of shape)

Question 6

Retina

Answer 6

6 lines the inner surface of the back of the eye and consists of specialized receptors that absorb light and send signals related to the properties of light to the brain

Question 7

Optic nerve

Answer 7

7 a dense bundle of fibres that connect to the brain - track ganglion cell activity (photoreceptor info)

Question 8

Optic disc

Answer 8

blind spot

Question 9

Rods

Answer 9

sensitive under low light levels - black, grey
(1:10, ganglion cells : rods)

Question 10

Cones

Answer 10

sensitive to diff wavelengths of light that we perceive as colour - located arround fovea
(1:1, ganglion cells : cones)

Question 11

Fovea

Answer 11

central region of retina

Question 12

Dark adaptation

Answer 12

is the process by which the rods and cones become increasingly sensitive to light under low levels of illumination = more rod activity

Question 13

Trichromatic theory

Answer 13

maintains that colour vision is determined by three different cone types that are sensitive to short, medium, and long wavelengths of light (Blue, green, red)

Question 14

Opponent-process theory

Answer 14

states that we perceive colour in terms of opposing pairs: red to green, yellow to blue, and white to black

Question 15

Optic chiasm

Answer 15

the point at which the optic nerves cross at the midline of the brain

Question 16

Feature detection cells

Answer 16

cells in the visual cortex that respond selectively to simple and specific aspects of a stimulus, such as angles and edges

Question 17

Ventral stream

Answer 17

a neural circuit for vision that extends from the visual cortex to the lower part of the temporal lobe - object recognition

Question 18

Dorsal stream

Answer 18

a neural circuit for vision that extends from the visual cortex to the parietal lobe - interaction w object

Question 19

Prospopagnosia

Answer 19

the ability to perceive objects as having constant shape, size, and colour despite changes in perspective

Question 20

Binocular depth cues

Answer 20

distances cues that are based on the differing perspectives of both eyes

Question 21

Convergence

Answer 21

Depth cue - eye muscles contract so both eyes focus on same object

Question 22

Retinal disparity (aka binocular)

Answer 22

Depth cue - the difference in relative position of an object as seen by both eyes, which provides information to the brain about depth

Question 23

Monocular cues

Answer 23

are depth cues that we can perceive with only one eye

Question 23

Pictorial depth cues

Answer 23

used by painters - texutre, linear perspective, etc

Question 24

Stereoscopic vision

Answer 24

overlapping visual fields - humans