M4S1: Basic Synaptic Plasticity Mechanisms

What are the 6 components of the synapse

smitter, cleft, chemically gated ion channels, voltage gated ion channels, synaptotagmin, synaptic vesicle

What are synaptotagmin? Where are they found? What are they activated by?

receptors, synaptic vesicle membranes, Ca2+

What does activation of synaptotagmin lead to?

exocytosis of synaptic vesicle

What is synaptic plasticity?

strengthening or weakening of synapses

What does synaptic plasticity depend on?

amount of neurotransmitter release and number of receptors on the postsynaptic membrane

How long does short term platicity last

seconds to mintues

What is synaptic facilitation? When does it occur? What does it result in?

transient increases in synaptic strength, when 2+ action potentials arrive at presynaptic terminal within miliseconds of one another, more NT release

Why does synaptic facilitation happen?

ca2+ is still in the presynaptic terminal when second action potential arrives and causes more vesicle exocytosis

When does synaptic depression occur? Why? What does this lead to?

during repeated stimulus of presynaptic neurons, there is a rapid decrease in available NT vesicles available for release, depression of the postsynaptic neuron

How long does the depression of the post synaptic neuron last in synaptic depression?

until stimulus cessation

What does synaptic depression allow for?

allows nervous system to code for the onset of events rather than signal every event

What is short term plasticity useful for?

habituation and sensory filting

What is the mechanism behind long term depression? What does this result in?

presynaptic neuron fires and the postsynaptic neuron is weakly activated by other inputs, weakening of synapse between pre and post synaptic neurons

What is the tennent of long term depression

neurons that fire out of synch lose their link

What is the mechanism behind long term potentiation?

presynaptic neuron fires and postsynaptic neuron is strongly activated ny other inputs at the same tume

What is the tennent of long term potentiation

neurons that fire together wire together

What are the three characteristics of LTP?

persistent, associative, input-specific

How is LTP persistent? What does this make it?

it is a persistent increase in synaptic strength, suitable long term memory storage mechanism

How is LTP associative

Requires coincident pre and post synaptic avtivity

How is LTP input specific?

When LTP is induced by stimulation of one synapse, there is no effect on other inactive synapses that contact that same neuron

look at slides like 14 and 15 which you skippped

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