disaster lecture

Question 1

when do you get spiking

Answer 1

when stimulus occurs in preffered direction but not null

Question 2

inhibitions role in DS

Answer 2

SAC provides inhibition

preferred gets firing when stimulus is on and off- ganglion cell connects to both layers of bipolar cells

Question 3

what is the mechanism for inhibition

Answer 3

dendrites of SAC cells are also DS

- starburst needs to mirror and connect to release GABA onto bipolar or ganglion cell

Question 4

what happens when you apply GABA blockers (picrotoxin)

Answer 4

see same response to preferred and null

Question 5

voltage clamp

Answer 5

measure glutamate: -60mV (reversal for GABA)
- see Glu input when stimulus comes in
- same size in preferred and null so must not be presynaptic cxn to bipolar cells
measure GABA: 0mV (reversal for glutamate)
- outward current larger in null, large inhibitory outputs
- prove that amacrine cell is DS and bipolar is not

Question 6

IV curves

Answer 6

inhibitory: crosses at -60, GABA
excitatory: crosses at 0, glutamate