visual system 2

Question 1

What are located in the same sublaminar int the IPL?

Answer 1

Axons of ON bipolar cells and dendrites of ON ganglion and amacrine cells

Question 2

Describe the circuitry of retina to respond to light going down

Answer 2

Have an OFF cell that terminates in one layer IPL and a ganglion cells the terminates in the same layer- they make connections – you have an off circuitry

Question 3

Describe the circuitry of the retina to respond to light increasing

Answer 3

Have ON cell which goes to different part of IPL and in same place have dendrites of an ON ganglion cell. They make connections

Question 4

What’s the function of amacrine cells?

Answer 4

can either stratify in specific layers in the IPL or stratify in/ have synapses everywhere in the IPL. Depending on function can either connect with OFF bipolar/ganglion cells, ON bipolar and ganglion cells or both.

Question 5

Describe the morphology of ganglion cells

Answer 5

very diverse.
They differ in the size of the dendritic trees, - some small some very dense
some are asymmetric, some are sparse and so on.

Question 6

Name a property of a ganglion cells receptive field

Answer 6

Has centre-surrounded organization – resulting from inhibitory feedback from amacrine cells.

Question 7

What are ganglion cells designed to respond to?

Answer 7

Differences in illumination that occurs within the receptive field.

Question 8

What happens if you shine light in centre of receptor field of ganglion cell?

Answer 8

OFF- centre: decrease in spiking

ON-centre: increase in spiking

Question 9

What are the two major classes of ganglion cells?

Answer 9

Parvocellular and Magnocellular

Question 10

Describe morphology and function of Parvocellular cell

Answer 10

Have small dendritic tree

Tuned to process information about shape and colour

Question 11

Describe morphology and function of Magnocellular cell

Answer 11

Have large dendritic trees

Process information about motion

Question 12

Describe response of parvocellular and magnocellular cells

Answer 12

Parvocellular: sustained - they keep spiking when shine light
Magnocellular: transient - Spike at stimulus onset and then stop spiking

Question 13

State conduction velocity of parvocellular and magnocellular cells

Answer 13

Parvocellular: Slow
Magnocellular: Fast

Question 14

State gain/sensitivity of parvocellular and magnocellular cells

Answer 14

Parvocellular: low
Magnocellular: high

Question 15

State function of parvocellular and magnocellular cells

Answer 15

Parvocellular: form/colour
Magnocellular: motion detection