It's composed of changes in how a set of neurons decide to fire. These changes occur at the synapse.
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What types of changes occur in the synapses to form a memory (2)?
Either in the message that is sent from one neuron, or how the message is received by the other.
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What causes synaptic facilitation?
Build up of Ca2+ in a cell. This triggers more exocytosis.
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How long do the effects of short term plasticity last?
10ms to a few minutes. These are only short term memories.
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What additional elements do long term memories require?
Excitatory synapses with the neurotransmitter glutamate, produced by second messenger systems.
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What is a second messenger?
One that is triggered by the first messenger (a neurotransmitter). They act inside the cell, modulating the action of specific proteins.
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What strengthens synapses?
If multiple neurons are made to fire at the same time.
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What are the two types of glutamate receptors that pyramidal neurons have?
AMPA and NMDA.
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What are some features of AMPA receptors (3)?
Normally ligand-gate, open if glutamate binds to them, cause an influx of Na+.
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What are some features of NMDA receptors (3)?
Ligand-gated and voltage-gated, when at rest the channels are blocked by Mg2+, allows Ca2+ to enter the cell.
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What is habituation?
A decrease in intensity of response to a stimulus when the stimulus is presented repeatedly.
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What is sensitisation?
An increase in intensity of response to a stimulus after the stimulus is presented alongside a novel or noxious stimulus.
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What is the mechanism for medium-term sensitisation?
Action potential in sensory neuron opens Ca channels ---> Influx of Ca2+ cause vesicles to release glutamate ---> Serotonin released from a third neuron onto another synapse ---> Activates G-protein that produces cAMP --
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*CONTINUED*
-> cAMP activate protein that interferes with K channel ---> K+ enters more slowly, Ca channels remain open longer ---> More Ca2+ enters ---> More glutamate released ---> Strong stimuli produce long-term changes in synapse.
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Other cards in this set
Card 2
Front
What types of changes occur in the synapses to form a memory (2)?
Back
Either in the message that is sent from one neuron, or how the message is received by the other.
Card 3
Front
What causes synaptic facilitation?
Back
Card 4
Front
How long do the effects of short term plasticity last?
Back
Card 5
Front
What additional elements do long term memories require?
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