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aNeuro Exam 3- Lindsey's > Vision > Flashcards

Flashcards in Vision Deck (114)
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1

The output neurons of the retina, the retinal ganglion cells, group together at ______.

the optic disk

2

____ are larger in the periphery of the retina..

Receptive fields

3

What happens after the 2 optic nerves converge @ the optic chiasm?

half of the axons from each eye cross to the other side and continue on as the optic tract

4

What do rods mediate?

black/white; light/dark vision

5

What does activation of transducing cause?

activation of cGMP phosphodiesterase (PDE)

6

What coordinates head and eye movements? Where is this structure located?

the superior colliculus; on the dorsal surface of the midbrain

7

These are central regions of the hypercolumns where color information is deciphered.

blobs

8

These cells capture photons of light and convert them into an electrical signal.

photoreceptor cells

9

What determines cortical wiring?

genetics

10

This is a .2mm wide region where acuity is the greatest.

the fovea

11

The period of time when the connections can be altered by visual experience is called ____.

the critical period (or sensitive period)

12

What is the dorsal parallel pathway?

  • from V1 dorsally --> parietal lobe
  • spatial vision
  • passes thru the thick stripe region of V2 and thru V5

13

What are binocular cells sensitive to?

depth perception

14

Layers 1, 4, and 6 of the lateral geniculate nucleus (LGN) of the thalamus receive input from the ______.

contralateral eye

15

What does the postsynaptic cell release to the presynaptic cell? When can the presynaptic cell take it up?

trophic factors; only when it's been recently active

16

_____ have donut-shaped receptive fields and come in on-center and off-center types.

Ganglion cells

17

Layers 3-6 of the lateral geniculate nucleus (LGN) of the thalamus receive inputs from the _____.

parvocellular ganglion cells

18

How many rods are in the human retina?

100 million

19

Category 4 ocular dominant cells are ____ driven.

equally (from both sides)

20

What do cones mediate?

color vision

21

What is hierarchical processing in the eye?

several cells with similar but spatially offset receptive fields converge on a higher order cell to create an altogether new type of receptive field

22

Beyond the lateral geniculate nucleus (LGN) of the thalamus, the axons fan out into the ______ to the visual cortex.

optic radiations

23

Receptive fields are larger in the ______ of the retina.

periphery

24

Each hypercolumn is divided into 2 parts, one half for each eye, called _____.

ocular dominance columns

25

What do complex cells do?

abstract for position

26

In the dark, the concentration of cGMP is ____, causing the nonselective cation channels to stay _____.

high; open

27

Layers 1 and 2 of the lateral geniculate nucleus (LGN) of the thalamus receive inputs from the _____.

magnocellular ganglion cells

28

What are the features of the parvocellular ganglion cells.?

object vision- color, form, detail high acuity --> fine detail small receptive fields not responsive to motion color vision (input from cones) layers 3-6 of the LGN

29

What are the 2 primary parallel pathways through the ascending visual system?

  1. the dorsal pathway
  2. the ventral pathway

30

What are the features of the magnocellular ganglion cells.?

spatial vision- motion and depth low acuity (crude) large receptive fields responsive to motion no color vision (input from rods) layers 1 and 2 of the LGN