Midterm 2

Question 1

electromagnetic waves

Answer 1

1. wavelength

2. intensity/amplitude

Question 2

wave length

Answer 2

• ability to see different colors/hues

- the distance between each wave

Question 3

intensity/amplitude

Answer 3

• how much energy is packed within a wave
• brightness
• amplitude of each wave

Question 4

cornea

Answer 4

does 90% of the focusing for the eye

Question 5

astigmatism

Answer 5

if the eye is not curved, the light does not come together in the back of the eye ->blurred image

Question 6

pupil

Answer 6

changes in diameter with the amount of light in the environment

Question 7

lens

Answer 7

• does 10% of the focusing

- accommodation: ability to change shape in order to bring an image into focus

Question 8

retina

Answer 8

• takes light rays and converge to the back of the eye
• IT IS APART OF THE BRAIN
• 5 layers

Question 9

retina - 5 layers

Answer 9

1. ganglion cells
2. amacrine cells
3. bipolar cells
4. horizontal cells
5. photo receptors (rods and cones)
   - cells that respond to light
   - only layer that actually detects sensation of the light

Question 10

in what sequence of cells layers is the information processed?

Answer 10

-in the opposite direction they are transmitted

Question 11

glacoma

Answer 11

fluid build up in the aqueous humor

Question 12

integration

Answer 12

information combines as it moves through the layers

Question 13

receptive field

Answer 13

every cell in the visual system is responsible for taking care of one part of the visual scene

• when struck by changing light, it causes the cell’s activity to change
• receptive field becomes larger and more complex as you move from one layer to the next

Question 14

rods

Answer 14

• 120 million in each eye
• organized on the outside of the retina (doughnut shape)
• respond to light, grey, dark, movement
• fast adapting cells
• low thresholds - very sensitive to light
• > work well in low/dim light conditions
• > helps respond to movement, even when you can’t completely see object - especially from the sides of the eye

Question 15

cones

Answer 15

• 6 million in each eye
• organized in the center of the retina
• tend to be slower acting
• > better for resolving fine detail
• lower light sensitivity
• > need more ambient light

Question 16

fovea

Answer 16

• point of central focus

- where the cones are - contains only cones

Question 17

cones - 3 kinds

Answer 17

1. short wave length for blue
2. medium wave length for green
3. long wave length for red

Question 18

nocturnal animals

Answer 18

mostly rods

Question 19

diurnal animals

Answer 19

mostly cones

-able to see more colors than animals with mostly rods

Question 20

radiance

Answer 20

light emanating directly from a light source

Question 21

anterior chamber

Answer 21

aqueous humor: circulating fluid

-helps maintain the shape of the eye

Question 22

“image forming eye”

Answer 22

an eye with a lens - developed in animals with backbones

Question 23

vitreous humor

Answer 23

• fluid chamber behind the lens

- the fluid is not renewed -> optical waste (shed cells)

Question 24

acuity - detection

Answer 24

ability to detect the smallest stimulus

Question 25

acuity - recognition

Answer 25

ability to recognize a character - name the target stimuli

Question 26

acuity - dynamic

Answer 26

follow object and keep a clear image - detection and location of moving target stimuli

Question 27

binocular overlap

Answer 27

region of the visual field that is seen in common by both eyes -enhances perception of depth and distance

Question 28

animals with lateral directed eyes

Answer 28

- two separate monocular fields | - visual field of 170 degrees

Question 29

animals with frontally directed eyes

Answer 29

- smaller monocular fields - large binocular overlap - visual field of 120 degrees

Question 30

primary visual cortex

Answer 30

- striate cortex - fibers from the lateral geniculate nucleus (LGN) terminate - V1

Question 31

dorsal stream

Answer 31

- important for spatial localization - "where" vision or ambient vision - low spacial frequency - predominates in the dark

Question 32

ventral stream

Answer 32

- important for object identification - resolving patterns with high spacial frequency - focal vision or "what" vision - highly cognitively mediated - consciously aware (form, pattern, motion, color)

Question 33

P cells

Answer 33

- parvus (small) - not many, mostly in the center - small cell bodies, small receptive fields - bad sensitivity - good for detail, wavelengths, vision, and color vision

Question 34

M cells

Answer 34

- magnus (large) | - distributed around the periphery of retina

Question 35

simple cells

Answer 35

responds only to precise orientation and must be in the center of the cell's receptive field -V1

Question 36

complex cells

Answer 36

larger receptive fields - prefers bars of light with specific orientation, but is more forgiving -> can be off center -can respond to movement

Question 37

hypercomplex cells

Answer 37

- optimally responsive to movement and to specifically oriented stimuli - responds best to stimuli of a particular length

Question 38

rhodopsin

Answer 38

- regenerates in darkness | - broken down when exposed to light

Question 39

saccade

Answer 39

a rapid and abrupt jump made by the eye as it moves from one fixation to another -most common eye movement

Question 40

80% of fibers that leave the eyes go to the ____

Answer 40

thalamus

Question 41

20% of the fibers that leave the eyes go to the ____

Answer 41

superior coliculus