Plasticity: LTP & LTD Flashcards
(33 cards)
Some patterns of synaptic activity produce a long-lasting increase in synaptic strength known as …
Long-term potentiation (LTP)
Some patterns of synaptic activity produce a long-lasting decrease in synaptic strength known as …
Long-term depression (LTD)
Long-term synaptic plasticity has been studied at excitatory/inhibitory synapses in the mammalian hippocampus/hypothalamus?
Excitatory, hippocampus
The hippocampus consists of 2 thin sheets o neurons folded onto each other, what is each sheet called
Denate Gyrus and Ammon’s Horn
CA3 and CA1 are divisions from what sheet
Ammon’s Horn
The Perforant path comes from…?
the Entorhinal cortex
The perforant path axons synapse on neurons of the _______
Dentate Gyrus
The Dentate gyrus gives rise to axons called____
Mossy fibres
The axons from the Dentate gyrus synapse on cells in _____
CA3
CA3 cells give rise to axons called____ and these synapse where?
Schaffer collaterals synapse in CA1
LTP has focused on synaptic connections between ______
Schaffer collaters and CA1 pyramidal cells
Electrical stimulation of Schaffer collaterals generates _______ postsynaptic potentials (__PSPs) in the postsynaptic CA1 cells
Excitatory
How is LTP caused?
High requency train of stimuli to the same axons
Where does LTP occur?
All 3 excitatory synapses in the hippocampus, cortex, amygdala, cerebellum
Increase/decrease in synaptic strength = LTP
What happends to the amplitude?
Increase in synpatic strength
Increase amplitude of AMPAr EPSC
What lobe is the hippocampus in?
Temporal lobe
LTP requires stong activity in…
Both Pre and post synaptic neurons
LTP occurs through depolarization of hyperpolarization?
Depolarization postsynaptically
Coincidence detector involves
Co-ordinated activity of presynaptic transmitter release and depolarization of the postsynaptic neuron
LTP is input specific, meaning?
LTP is restircted to activated synapses rather than to all of the synapses on a given cell.
Another properity of LTP is Associativity, what does this mean?
Co-operative. If 1 path is weakly activated at the same time athat a neighbouring pathway onto the same cell is strongly activated, then both synaptic pathways undergo LTP.
Describe the 3 phases of LTP..
Induction: Stimulation that induces an increase in synaptic strength (blocking this phase inhibits the other phases). Though activation of NMDA receptors
Expression: How synaptic strength is increases
Maintenance: How to maintain the increase in synaptic strength. Through insertion of AMPA receptors
How LTP works….
- High frequency stimulation causes prolonged depolarization
- this expels Mg2+ from NMDA receptors
- Ca2+ can now enter though the NMDAr into the postsynaptic neuron.
- Ca2+ influx activates signal transduction cascades, including CaMKII & PKC
- CaMKII induces phosphorylation of AMPA receptors
- This causes more AMPA receptors to be inserted at the postsynaptic membrane, + Increases AMPAr conductance
- This Increase synapse strength = LTP
Why does NMDA behave like a co-incidence detector?
The channel wil only open when Glutamate is bound to the receptor + the post-synaptic cell is depolarized to relieve the Mg2+ block
