vision Flashcards

receptive fields: explain the purpose of receptive fields

1
Q

2 features of central (foveal) vision

A

detail day vision, colour vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is responsible for central vision

A

fovea, as highest concentration of core photoreceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is central vision used for

A

reading, facial recognition etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how is central vision assessed

A

visual acuity assessment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what does loss of foveal vision result in

A

poor visual acuity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

3 features of peripheral vision

A

shape, movement, night vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is peripheral vision used for

A

navigation vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

how is peripheral vision assessed

A

visual field assessment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

effects of extensive visual field loss

A

unable to navigate in environment, so may need white stick even with perfect visual acuity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the receptive field of a neurone

A

retinal space within which incoming light can alter pattern of a neurone (positive signal from stimulated photoreceptor, and negative signals from all others, to single ganglion cell)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the receptive field of a photoreceptor

A

small circular space surrounding photoreceptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is convergence

A

where retinal ganglion cells receive input from neighbouring photoreceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

diagram of receptive field

A

slide 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

define convergence

A

number of lower order neurones field synapsing on same higher order neurone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

cone vs rod system convergence

A

cone > rod

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

central vs peripheral retina convergence

A

central > peripheral

17
Q

low convergence: receptive field, visual acuity, light sensitivity

A

small receptive field, fine visual acuity, low light sensitivity

18
Q

high convergence: receptive field, visual acuity, light sensitivity

A

large receptive field, coarse visual acuity, high light sensitivity

19
Q

2 types of ganglion cells

A

on-centre, off-centre

20
Q

what are on-centre ganglion cells stimulated by (and off-centre ganglion cells inhibited by)

A

light at centre of receptive field

21
Q

what are on-centre ganglion cells inhibited by (and off-centre ganglion cells stimulated by)

A

light on edge of receptive field

22
Q

what are on-centre and off-centre ganglion cells important for

A

contrast sensitivity, enhanced edge detection

23
Q

where is lowest convergence

A

fovea as 1:1:1 (1 cone, 1 bipolar cell, 1 retinal ganglion cell)