L10 - Synaptic Integration

Question 1

What is EPSP, IPSP and input?

Answer 1

Excretory inputs: +ve ions inside

Inhibitory input: -ve ions inside

Input: EPSP-IPSP (if above threshold will cause an AP)

Question 2

What factors affect the decision to fire an AP?

Answer 2

1. Net input
2. Strength of input

Also: Location of synapse and firing frequency

Question 3

Spacial summation (dendrites)

Answer 3

Dendrite SA > Cell body

Passive diffusion - EPSP unlikely to reach threshold (further from hillock - less influence)

Question 4

Temporal summation

Answer 4

PSP additive

Pre synaptic transmitter runs out quickly

Question 5

Spatial vs Temporal

Answer 5

Spacial: combined = AP

Temporal: Increase pre transmitter frequency = AP

Question 6

Shunting Inhibition

Answer 6

Single inhibitory synapse close to soma can switch off all other inputs to that dendrite.

Question 7

FM code

Answer 7

Frequency and pattern = convey information

Question 8

Reson for encoding (2)

Answer 8

1. Prevent firing at low stimulation levels

2. Fire at a frequency proportional to stimulus