Quiz 2 Flashcards
What are the 3 key downstream signalling molecules of INDUCTION of LTP at the Schaeffer collateral synapse?
- CAMKII is activated by auto-phosphorylation
- Nitric Oxid synthase signals trans-synaptically to the presynaptic terminal
- Protein Kinase C triggers AMPA receptor insertion
What are 2 mechanisms of EXPRESSION of LTP at the Schaeffer collateral synapse?
- More neuratransmitter released
- More AMPARs and more sensitive AMPARs to pick up neurotransmitter signal with
When p changes, is the LTP pre or post synaptic?
p vesicle change = presynaptic expression
When q (quantal amplitude) changes, is the LTP pre or post synaptic?
quantal amplitude change = postsynaptic expression
When n changes, is the LTP pre or post synaptic?
neither
What does late LTP requires that early LTP does not require?
protein synthesis
How can late LTP be expressed?
via addition of contacts (n increased)
What could NMDAR dependance explain?
- Cooperatively
- Input specificity
- Associativity
Why does high frequency stimulation induce LTP?
because the is accumulation of Ca2+
If STP (ratio) is affected, where is the LTP expressed?
On the presynaptic side
What is spike-timing-dependant plasticity?
pre before post firing
(aligned with Hebbian postulate if pre fires just before post (within 25ms)
If post fires before or more than 25ms after –> LTD
How is CV found?
CV = SD/mean
How does changes in noise (failure peak) affect CV?
p release causes noisy neurotransmission so changes in noise levels implies change in p release
CV is a measure of noise
How is LTD expressed pre and post-synaptically?
Pre: reduction of Ca 2+ available (reduces p release)
Post: partial blocking of AMPA receptors with CNQX (reduces quantal amplitude)
To what is p proportional?
p proportional to 1/CV^2
How is background noise level seen in the graph?
wider peaks
When does quantal analysis become ineffective (not precise enough)?
When noise levels or n increase beyond a certain point
How can yuo calculate p with a quantal release graph (where you have the peaks and or cumulative)?
- Do weight avg
- E=npq (isolate p)
What are 3 ways to assess indirectly the expression of LTP?
- Analysis of the rate of failure
- Analysis of STP
- Analysis of CV (When too much noise of n in the quantal release graph, treat it as 1 binomail distribution)
For LTD, on the CV analysis graph, where are the arrows for pre and post-synaptic plasticity?
mean normalized < 1
PRE = under diagonal
POST = over diagonal
*makes a line between pre for LTP and LTD
For LTP, on the CV analysis graph, where are the arrows for pre and post-synaptic plasticity?
mean normalized > 1
PRE = over diagonal
POST = under diagonal
How does 1/CV2 change for pre and post synaptic LTP?
PRE: 1/CV2 changes (p release changes)
POST: CV does not change are SD and mean scale up or down together
The width of a typical action potential at half of its height is: 1 μs, 1 ms, or 1 ns?
1 ms
The magnitude of a connection from one layer-5 pyramidal cell to another layer-5 pyramidal cell could be: 1 nA, 1 μS, or 1 mV?
1 mV
