Visual System

Question 1

What is the visual system designed to recognise and localise?

Answer 1

Food
Predators
Mates

Question 2

The morphology of sensory neurons is largely defined by its ________

Answer 2

Function

Question 3

What is the superior colliculus responsible for?

Answer 3

Attentional vision (turning to focus on something)

Question 4

The retina consists of __ layers of neurons and __ layers of synapses

Answer 4

3

2

Question 5

Feedforward neurons are…

Answer 5

Photoreceptors
Bipolar cells
Ganglion cells

Question 6

Feedback neurons are…

Answer 6

Horizontal cells

Amacrine cells

Question 7

Layers of synapses

Answer 7

Inner and outer plexiform layers

Question 8

Rods are active at ___ light

Answer 8

Dim

Question 9

Cones are active at ____ light

Answer 9

Bright

Question 10

ON bipolar cells _____ in response to light

Answer 10

Depolarise

Question 11

OFF bipolar cells _____ in response to light

Answer 11

Hyperpolarise

Question 12

What is the receptive field?

Answer 12

An area in the retina which when illuminated activates a visual neuron

Question 13

The optic nerve is the information…

Answer 13

Bottleneck

Question 14

Right visual field activates the _____ side of the brain and vice versa

Answer 14

Left

Question 15

What is the main function of the retina?

Answer 15

Image acquisition

Question 16

What does the lateral geniculate nucleus do?

Answer 16

Sends information to the primary visual cortex

Preprocesses visual information

Question 17

What is the superior colliculus responsible for?

Answer 17

Attentional

Focusing on the visual field

Question 18

Two main visual pathways

Answer 18

Ventral

Dorsal

Question 19

Ventral pathway

Answer 19

What pathway
Object feature stream
Jennifer Anniston neurones

Question 20

Dorsal pathway

Answer 20

Where pathway
Space related stream
Useful for sport to position ourselves to catch a ball etc

Question 21

Where is the ventral pathway?

Answer 21

Inferior temporal lobe

Question 22

Where is the dorsal pathway?

Answer 22

Posterior parietal lobe

Question 23

What does the pupil do?

Answer 23

Regulates the amount of light falling on the retina

Question 24

What does the lens do?

Answer 24

Focuses the image on the fovea

Question 25

What is the fovea?

Answer 25

Part of the retina with highest visual acuity

Question 26

The rest of the retina has _____ acuity and contains primarily _____

Answer 26

Smaller | Rods

Question 27

Light travels through ____ cells

Answer 27

Muller

Question 28

Horizontal cells

Answer 28

Feedback to photoreceptors | Feedforward to bipolar cells

Question 29

Amacrine cells

Answer 29

Most diverse type of cell in retina Inhibitory Send feedback to bipolar cell (inhibit bipolar cells) Feedforward to ganglion cells

Question 30

Phototransduction happens in the _____ segment

Answer 30

Outer

Question 31

Photoreceptors respond to light flashes by...

Answer 31

Hyperpolarisation

Question 32

In darkness, the sodium calcium channel is ____ and the membrane is _____

Answer 32

Open Depolarised (influx of sodium and calcium ions makes the membrane less negative)

Question 33

Why are photoreceptor synapses special?

Answer 33

They have ribbon synapses Can release vesicle constantly Do not spike, have graded potentials Release glutamate

Question 34

When light goes up, the release rate of glutamate goes _____ and vice versa

Answer 34

Down

Question 35

ON cells ____ when you apply glutamate

Answer 35

Hyperpolarise

Question 36

What is centre surround organisation of the receptive field?

Answer 36

Illumination of the centre leads to an opposite response to illumination of the surround Centre depolarises Surround hyperpolarises

Question 37

Mechanism of centre-surround organisation

Answer 37

Many photoreceptors coverage to 1 bipolar cell Photoreceptors in the centre, directly synapsed to bipolar cells Peripheral photoreceptors synapse to the horizontal cell and therefore cause bipolar cell to depolarise

Question 38

Centre mechanism

Answer 38

Light Hyperpolarises photoreeptor Transmitter (glutamate) stops being released Bipolar cell hyperpolarises

Question 39

Surround mechanism

Answer 39

``` Light Hyperpolarises photoreceptor Hyperpolarises horizontal cell Stops hyperpolarising photoreceptor Bipolar cell depolarises ```

Question 40

Do ganglion cells spike?

Answer 40

Yes

Question 41

What happens when you stimulate the centre of an off-centre ganglion cell?

Answer 41

They stop spiking

Question 42

What happens when you stimulate the surround of an off-centre ganglion cell?

Answer 42

They spike more frequently

Question 43

What happens when you stimulate the surround of an on-centre ganglion cell?

Answer 43

They stop spiking

Question 44

What happens when you stimulate the centre of an on-centre ganglion cell?

Answer 44

They spike more frequently

Question 45

It appears that ganglion cells are designed to respond to ______ in illumination that occur within the receptive field

Answer 45

Differences

Question 46

If you have an illumination which covers the whole receptive field evenly, _____ of cells _____ spike.

Answer 46

The majority | Would not

Question 47

Two major classes of ganglion cells

Answer 47

Parvocellular (80%) | Magnocellular (10%)

Question 48

P cells have ____ dendrites than M cells

Answer 48

Smaller but more densely packed

Question 49

P cells have ____ receptive fields than M cells

Answer 49

Smaller

Question 50

P cells are known as

Answer 50

Sustain cells

Question 51

M cells are known as

Answer 51

Transient cells