Vision Flashcards
1
Q
Amplitude =
A
brightness
2
Q
Wavelength =
A
color
3
Q
3 Properties of Light
A
- reflection
- absorption
- refraction
4
Q
Accomodation
A
- unaccomodated: far distance vision, flat lense, ciliary muscle relaxed
- accomodated: near vision, fat lens, ciliary muscle contracts and zonule fibers relax
5
Q
Cones vs Rods
A
- cones: 8 million cones, not functional in low light
- rods: 100 million rods
6
Q
Rhodopsin
A
- opsin + retinal
- opsin= 7 transmembrane spanning protein
- retinal= light sensitive molecule
7
Q
Phototransduction
A
- light -> rhodopsin -> activates G protein transducin -> activates cGMP phosphodiesterase -> hydrolyzes cGMP
- ultimately light reduces concentration of cGMP
- light causes hyperpolarization and dec. NT release
8
Q
Retinal Ganglion Cell Responses
A
- if light hits positive ganglion receptors, action potentials fire
- if dark hits positive ganglion receptors, action potentials fire after stimulus is turned off (rebound response)
9
Q
Mach Bands
A
-psychological effect thought to reflect center/surround organization of visual system
10
Q
Lateral Genticulate Nucleus
A
- eye of origin remains separate in LGN layers (contralateral ball= 1, 4, 6 & ipsilateral ball= 2, 3, 5)
- no binocular interaction in LGN
- layers 1, 2 are magnocellular
- layers 3, 4, 5, 6 are parvocellular
11
Q
Parvocellular System
A
- object vision
- layers 3, 4, 5, 6 of LGN
- fine detail, small receptive fields, -not receptive to motion
- color vision from cones
12
Q
Magnocellular System
A
- spatial vision
- crude form
- large receptive field
- responsive to motion
- no color vision (input from rods only)
13
Q
Hierarchical Organization
A
- simple cell receptive field (RF) created from converging LGN neurons with center surround receptive fields
- simple RF is elongated
- complex cell receptive field created from converging cortical neurons with simple cell receptive fields
14
Q
Striate Cortex
A
- where binocular vision occurs-
- conversion of input from both eyes
15
Q
Superior Colliculus
A
- has a somatotopic visual map and auditory map layered over the visuospatial map for saccades
- If superior colliculus is damaged, saccades are less acurate and occur less often
