Synaptic Transmission 2 Flashcards
(40 cards)
What is synaptic plasticity?
the ability of the synapse to change its properties depending on its recent level of activity
What is thought to be the basis of learning and memory?
synaptic plasticity
Describe how to record long-term potentiation/plasticity. Which structure of the brain is involved?
- stimulate schaffer collaterals
- CA3 releases NTs
- CA1 stimulated
- record CA1 activity
(in hippocampus)
What kind of memory is the hippocampus mainly involved in?
spatial memory
What is the cellular correlate of learning and memory?
LTP
What is the specificity and associativity of LTP?
- specificity: synapse strengthened for pathways highly activated (at high frequencies)
- associativity: b/c path 2 fires with path 1, both paths’ synapses are strengthened
TRUE or FALSE: in synaptic plasticity, a larger presynaptic stimulus results in a larger post-synaptic response (in comparison to baselin)
FALSE: SMALLER stimulus results in SIMILAR response
Draw a diagram using 3 different neurons to demonstrate how synaptic strength can be increased.
slide 6
TRUE or FALSE: highly active synapse = strengthened synapse
TRUE
TRUE or FALSE: changes in the postsynaptic cell lead to a strengthened synapse
FALSE: changes in both pre and postsynaptic cells are requireD
How did Donald Hebb describe the mechanism for the strengthening of synapses?
some growth process or metabolic change takes place in one or both cells so that A’s EFFICIENCY as one of the cells firing C is increased
What are the 2 properties of LTP?
specific and associative
What is the Hebbian definition for LTP?
an enduring increase in synaptic efficacy resulting from an activity dependent (Hebbian) process
Where was LTP first discovered in the brain? Where has it been shown to exist?
hippocampus; most glutamatergic synapses in the brain
What are the 2 requirements to get a larger postsynaptic event?
- more receptors on surface
- increase conductance states of channels (more ions flow into post cell
Before tetanic stimulation, the slope of the synaptic potential is _________. After, it is ________.
low; high
How long can LTP last?
days to weeks
What are the 3 LTP phases?
- early - INDUCTION phase
- medium - EXPRESSION phase
- late - MAINTENANCE phase
In summary, what occurs during the early induction phase of LTP?
NMDA receptor activation and calcium dependence
In summary, What occurs during the medium expression phase of the LTP?
- changes to receptors and release machinery
- local protein synthesis
In summary, What occurs during the late maintenance phase of the LTP?
- genomic involvement
- translation dependent
- anatomical changes?
TRUE or FALSE: after tetanic stimulation, synaptic currents are smaller in amplitude
FALSE: larger amplitude
At what frequency should you tetanically stimulate a cell to induce LTP?
100 Hz
Describe the mechanism of the induction phase of LTP.
- NMDAR activated –> double-gated coincidence detector (ligand-dependent AND voltage-dependent…bind glu, remove Mg2+)…see notes in previous unit
- Ca2+ entry through NMDA
- increase Ca2+ intracellular triggers increase in post responsiveness: increases in post AMPAR, pre NT release, and synaptic contacts
- LTP is induced
- this INDUCES LTP
(i.e. unblock NMDA –> Ca2+ flows in –> express LTP)
