Term
| What is the term for synaptic responses not always being the same size when an action potential occurs? (there are activity dependent alterations in the strength of the synapse) |
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Definition
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Term
| Short term plasticity lasts how long? |
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Definition
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Term
| 3 types of short term plasticity are? |
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Definition
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Term
| After a high frequency stimulus, there is a potentiation of a response-this is what type of short term plasticity? |
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Definition
| post-tetanic potentiation |
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Term
| Increase in synaptic strength that lasts at least 30 minutes? |
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Definition
| LTP (Long-term potentiation) |
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Term
| Long Term Plasticity expression is usually (presynaptic/postsynaptic) and causes changes in (presynaptic/postsynaptic) receptors. |
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Definition
| Long Term Plasticity- postsynaptic |
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Term
| What are the 3 parts of long term potentiation? |
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Definition
1. Induction
2. Expression
3. Maintenance |
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Term
| Most forms of long term plasticity depend on ___ entry, usually through ____ receptors |
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Definition
calcium entry
usually enters through NMDA receptors |
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Term
T or F
Long term maintenance requires protein synthesis |
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Definition
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Term
| Is long term plasticity reversible? Is it saturable? |
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Definition
| Long term plasticity is both reversible and saturable |
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Term
| Repeating the same stimulus will get more and more long term potentiation (LTP) up to a point. If you repeat the stimulus enough times, then you max out - this is called the ___ of long term plasticity |
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Definition
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Term
| Why is saturability important in long term plasticity? |
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Definition
| If you maxed out LTP then you would be unable to have additional learning. |
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Term
| synapses that potentiate (long term potentiation) can also depotentiate, which is called what? |
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Definition
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Term
| LTP can last how long in vivo? |
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Definition
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Term
| what is believed by many scientists to be a cellular correlate of learning and memory? |
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Definition
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Term
| The ____ synapse is the iconical synapse for studying excitatory long term plasticity. |
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Definition
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Term
| Induction of LTP can occur through which 2 mechanisms? |
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Definition
1. High frequency burst stimulation (tetanus)
2. Pairing low frequency stimulation with a postsynaptic depolarization |
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Term
| LTP induction is Hebbian…what does this mean? |
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Definition
| It requires coincident presynaptic and postsynaptic activity. (Requires presynaptic release of glutamate because NMDA receptors do not function without glutamate binding. Binding of glutamate causes depolarization and removal of Mg2+ block) |
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Term
| What is the summary of the induction of plasticity (explain "Neurons that fire together, wire together" |
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Definition
| When an axon of cell A is near enough to excite cell B repeatedly or consistently takes place in firing it, some growth process or metabolic change takes place in one or both cells such that A’s efficiency, as one of the cells firing B, is increased. (Neurons that fire together increase the strength of the connection between them) |
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Term
| bursts of high frequency stimulation called what? |
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Definition
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Term
| example of tetanic stimulation is two __sec, ___Hz tetani with a 20 second interval |
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Definition
| example of tetanic stimulation is two 1 sec, 100Hz tetani with a 20 second interval |
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Term
| example of tetanic stimulation is two __sec, ___Hz tetani with a 20 second interval |
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Definition
| example of tetanic stimulation is two 1 sec, 100Hz tetani with a 20 second interval |
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Term
| Pairing-induced LTP - one experiment found that NO LTP occurs in the control pathway that (was paired, was not paired) with postsynaptic depolarization |
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Definition
Pairing-induced LTP - one experiment found that NO LTP occurs in the control pathway that was not paired with postsynaptic depolarization.
The test group paired postsynaptic depolarization with low frequency presynaptic stimulation and did have LTP |
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Term
| what do the two methods of induction of LTP have in common? |
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Definition
1. Presynaptic stimulation (release of glutamate
2. postsynaptic depolarization |
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Term
| Synaptic transmission at excitatory glutamate synapses is mediated by what 2 receptors |
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Definition
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Term
| At resting membrane potentials, (NMDA/AMPA) receptors are blocked by Mg2+ and all current is carried by (NMDA/AMPA) receptors |
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Definition
| Resting membrane potentials - Mg+ is blocking NMDA receptorsand all current is carried by AMPA receptors |
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Term
At depolarized potentials in excitatory glutamate synapses,
a. AMPA receptors carry current
b. NMDA receptors carry current
c. Both a and b
d. None of the above |
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Definition
| c. Both AMPA and NMDA receptors carry current at depolarized potentials |
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Term
| Ca+ flux the cell is important for what? Ca+ flows through (NMDA/AMPA) receptors |
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Definition
| Ca+ flux into the cell is important for LTP. It flows through NMDA cells at depolarized potentials (after cell is depolarized) |
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Term
| LTP relies specifically on ___ receptor activation |
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Definition
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Term
| Important point: LTP induction depends on ___ receptors |
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Definition
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Term
| During strong stimulation (such as tetanus), current through _1__ receptors depolarizes postsynaptic cells and relieves the _2__ block on _3__ receptors, allowing Ca+ influx through _3_ receptors |
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Definition
1. AMPA 2. Mg2+ 3. NMDA
[image] |
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Term
| After tetanus is over, ___ returns to block ____ receptors, anc Ca+ influx stops |
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Definition
| Mg2+ returns to block NMDA receptors |
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Term
| blocking NMDA receptors with Mg2+ blocks what? |
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Definition
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Term
| Intracellular calcium chelators are in the (presynaptic/postsynaptic) cells. They do what? |
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Definition
They bind calcium. if all calcium that comes through NMDA receptors is bound, then LTP is prevented.
(To chelate just means to pinch or grab-crabs have chelae. Just think that chelators grab Ca+ and STOP LTP. "Chee ya later LTP!") |
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Term
| In what ways could the synapse be altered (plasticity) presynaptically? postsynaptically? combination/other? |
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Definition
1. You could have an increase in the amount of glutamate being released
2. You could have a change that affects the AMPA receptors that now causes a stronger postsynaptic response to the same amount of glutamate.
3. New or altered postsynaptic receptors |
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Term
| A synapse that is present, but is not active in synaptic transmission |
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Definition
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Term
T or F
A silent synapse could either be presynaptically silent “Mute” or postsynaptically silent “Deaf” |
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Definition
True
presynaptically silent - not releasing glutamate
postsynaptically silent - not responding to glutamate |
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Term
| hypothesis about silent synapses and LTP? |
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Definition
| LTP increases the synaptic response by activating previously silent synapses |
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Term
| Postsynaptically silent CA3-CA1 synapses are found where? |
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Definition
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Term
| Postsynaptically silent synapses may have __1__ receptors, but no __2__ receptors. After LTP, you get insertion of the __2__ receptors |
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Definition
1. NMDA
2. AMPA
... so the cell will be functionally silent at resting membrane potentials |
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Term
| Postsynaptic CaMKII (calcium calmodulin dependent kinase II) is required for what? |
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Definition
| to phosphorylate postsynaptic AMPA receptors and insert AMPA receptors, and the AMPA receptors existing in synapses also get phosphorylated so they can actually increase their responsiveness. |
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Term
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Definition
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Term
| How can LTP last so long? |
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Definition
- In Early LTP, CaMKII activity persists even after Calcium returns to baseline
- In Late LTP, CREB leads to protein synthesis and formation of new synapses- LTP maintenance requires protein synthesis |
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Term
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Definition
cyclic-AMP response element binding protein
- transcription factor in late LTP that leads to production of new proteins and new synapses |
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Term
| Long term depression is induced by (high/low) frequency activity for a (short/long) period of time |
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Definition
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Term
| 1 Hz for fifteen minutes is the standard protocol for inducing LTD. You get an initial facilitation (short-term plasticity), but after 1 Hz stimulation, when you go back to the baseline stimulation, what happens? |
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Definition
| decrease in synaptic response |
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Term
| LTP activates postsynaptic kinases, whereas LTD activates postsynaptic |
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Definition
| phosphatases (Calcium dependent) |
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Term
| LTD requires (larger/smaller) increase in calcium as opposed to LTP? |
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Definition
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Term
| LTD (phosphorylates/dephosphorylates) AMPA receptors |
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Definition
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Term
| these excitatory cells in the hippocampus encode info about the animal's physical location in space (SPATIAL INFORMATION) |
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Definition
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Term
| this part of the brain involved in mice remembering where platform is in pool (they love this experiment) |
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Definition
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Term
| mice with NMDA knocked out in place cells- is there any effect? |
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Definition
| yes- bad effect. Losing NMDA receptor-dependent LTP impairs place fields |
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Term
| Do the NMDA receptors affect learning, spatial memory, or both in the Morris mouse water maze? |
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Definition
| Spatial MEMORY - not learning |
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