Fast Synaptic Transmission & Plasticity (Theme B)

Question 1

What is synaptic plasticity?

Answer 1

The ability of synapses to change in strength, efficacy & structure in response to experience, neural activity and learning

Includes long-term potentiation (LTP) & long-term depression (LTD) of synapses

Question 2

What is long-term potentiation (LTD)?

Answer 2

Long-lasting increase in synapse strength

Question 3

What is long-term depression (LTD)?

Answer 3

Long-lasting decrease in synapse strength

Question 4

The integration of multiple responses at the synapse depends on what? (2)

Answer 4

Where the synapses are relative to each other & the soma

The timing of the responses in terms of their onset & time course

Question 5

The postsynaptic current response to release of transmitter at a fast central synapse is determined by what?

Answer 5

Type, number & conductance of postsynaptic receptors
Probability of NT release
Number of release sites

Question 6

The voltage response to a synaptic current measured at the soma depends on what?

Answer 6

Size & time course of current response
Position of the synapse on the postsynaptic cell
Input (membrane) resistance (what channels are open at the time)
Capacitance (membrane surface area)

Question 7

What is synaptic integration?

Answer 7

The process by which a neurone combines multiple signals it receives from different synapses

Question 8

What are the 3 things involved in synaptic integration?

Answer 8

Spatial summation
Temporal summation
Dendritic filtering

Question 9

What is spatial summation?

Answer 9

• The integration of signals from DIFFERENT synapses that are spatially close to each other on a neurone’s dendrites
• The combined effect of these signals can lead to the generation of an AP if the overall input exceeds the neuron’s threshold

Question 10

What is temporal summation?

Answer 10

• The integration of signals that arrive at the same synapse, but at different times
• If a neuron receives repeated signals in a short time frame, the individual effects of these can summate to trigger an AP

Question 11

What is dendritic filtering?

Answer 11

The process by which a neurone’s dendrites modify & filter incoming synaptic signals before they reach the cell body

Question 12

Dendritic filtering determines what about the voltage response?

Answer 12

The voltage amplitude & time course