Vision

Question 1

Lens

Answer 1

Bends light to focus it on retina.

Question 2

Iris

Answer 2

Controls how much light enters the pupil thru ciliary muscle

Question 3

Cornea

Answer 3

Transparent outer layer of the eye whose curvature is fixed. For protection and refraction. Corrects bending of light. Primarily responsible for forming image on retina

Question 4

Accommodation

Answer 4

The process of focusing by the ciliary muscles and the lens to form a sharp image on the retina.

Question 5

Extraocular muscle

Answer 5

One of the muscles attached to the eyeball that control its position and movements

Question 6

Retina

Answer 6

The receptive surface inside the eye that contains photoreceptors and other neurons

Question 7

Rods

Answer 7

A class of light-sensitive receptor cells in the retina that are most active at low levels of light.
Photopigment= rhodopsin
Part of scotopic system.
Get many rods per ganglion

Question 8

Cones

Answer 8

A class of photoreceptors cells in the retina that are responsible for color vision 
Has three classes of photopigments. 
Small receptive field.
Photopic system. 
One come per ganglion cell.

Question 9

Bipolar cells

Answer 9

A class of interneurons of the retina that receive info from rods and cones and pass info to retinal ganglion cells. 
Can only pride graded potentials. Release GLU

Question 10

Ganglion cells

Answer 10

A class of cells in the retina whose axons form the optic nerve.
Produce action potentials
Have concentric receptive fields

Question 11

Photoreceptors

Answer 11

Neural cells in the retina that respond to light (rods and cones)
Can only produce graded potentials

Question 12

Range fractionalization

Answer 12

A hypothesis of stimulus intensity perception stating that a wide range of intensity values can be encoded by a group of cells, each of which is a specialist for a particular range of stimulus intensities. Different receptors handle different intensities, diff thresholds

Question 13

Photoreceptors adaptation

Answer 13

The tendency of rods and cones to adjust their light sensitivity to match ambient levels or illumination

Question 14

Lateral inhibition

Answer 14

Info processing that takes place in the eye where some cells cause neighboring cells to be quiet so they can focus.
Done by horizontal and amacrine cells.

Question 15

Horizontal cells

Answer 15

Specialized retinal cells that contact both the receptor cells and the bipolar cells
Involved in lateral inhibition

Question 16

Amacrine cells

Answer 16

Specialized retinal cells that contact both bipolar and ganglion cells and are significant in inhibitory interactions within the retina

Question 17

Visual field

Answer 17

Whole area that you can see without moving head or eyes

Question 18

Fovea

Answer 18

Central portion of the retina packed with most photoreceptors and therefore center or our gaze. Densely packed with cones

Question 19

Optic disc

Answer 19

Region of retina devoid of receptor cells bc ganglion cells axons and blood vessels exit the eyeball there. Makes blind spot in vision

Question 20

Neural pathway of vision

Answer 20

From ganglion cells form optic nerve, to optic chiasm (nasal vs temporal crossing over), to lateral geniculate nucleus (LGN), to optic radiation (thalamus to cortex), to primary visual cortex (V1) in occipital lobe aka striate cortex.

Question 21

On-center bipolar cells

Answer 21

A retinal bipolar cells that is excited by light in the center of its receptive field because it receives less GLU rich would inhibit it.

Question 22

Off-center bipolar cell

Answer 22

A retinal bipolar cell that is inhibited by light in the center of its receptive field. Is excited by turning off light in center, receives more GLU which depolarizes it.

Question 23

On-center ganglion cell

Answer 23

A retinal ganglion cell that is activated (depolarized by GLU from on-center bipolar cells) when light is presented to the center, rather than the periphery, of the cell’s receptive field.

Question 24

Off-center ganglion cell

Answer 24

A retinal ganglion cell that is activated (depolarized by GLU from off center bipolar cells) when light is presented to the periphery, rather than the center, of the cell’s receptive field.

Question 25

Concentric receptive fields

Answer 25

Two types:
On-center/off-surround
Off-center/on-surround

Question 26

LGN

Answer 26

6 layers of cells
Outer 4 layers-parvocellular (small receptive fields, fovea, high acuity)
Inner 2 layers- magnocellular (low acuity, large receptive fields, not detailed)

Question 27

V1

Answer 27

Has simple and complex cortical cells, feature detectors (grandmother cells theory), hierarchical processing.

Question 28

Simple cortical cell

Answer 28

Aka bar/edge detector.
Cell in visual cortex that responds best to an edge or a car that had s particular width, as well as a particular orientation and location in the visual field. Simple features, respond to light, small area.

Question 29

Complex cortical cells

Answer 29

A cell in the visual cortex that responds best to a bar or particular size and orientation anywhere within a particular area of the visual field. More features

Question 30

Spatial frequency filler model

Answer 30

A model patten of analysis that emphasizes Fournier analysis of visual stimuli

Question 31

V1 columns

Answer 31

Run parallel to surface of cortex.
4 dif types:
Location, ocular dominance (depth perception, kitten studies), spatial orientation, color.

Question 32

Ocular dominance column

Answer 32

A region of cortex in which one eye provides greater degree of synaptic input

Question 33

Orientation column

Answer 33

A column of visual cortex that responds to rod-shaped stimuli of a particular orientation.

Question 34

Trichromatic theory

Answer 34

Three diff types of cones (red blue green) that respond to diff types of light. Actually 3 types of cones- short, medium, long. Only happens at level of cones

Question 35

Opponent- process theory

Answer 35

Color pairs: red-green, black-white, yellow-blue. In bipolar/ganglion cells, excited by one color, inhibited by another.
If color blind, missing an opsin

Question 36

Motion perception

Answer 36

In cortical area V5. If can’t perceive motion, lack columns that perceive motion in medial temporal area in temporal lobe.

Question 37

Dorsal stream of vision

Answer 37

“Where” pathway.

V1, to medial temporal area, to parietal lobe, to frontal lobe.

Question 38

Ventral stream of vision

Answer 38

“What” pathway. Object identification.

V1, to inferior temporal area (fusiform gyrus facial rec), to frontal.

Question 39

Optic ataxia

Answer 39

Difficulty hating vision to reach and manipulate objects. From damage to posterior parietal cortex “where” pathway.

Question 40

Myopia

Answer 40

Nearsightedness. Eyeball is too long, object image focused in front of retina instead of on it. Spending time indoors w artificial light could be cause