06 | Plasticity Flashcards
What indicates the strength of a synapse (electrophysiology)?
amplitude of potential
changes in synaptic efficiency due to spike trains is called…
activity-dependent synaptic plasticity
List the short-term plasticity responses
- Facilitation
- Depression
- Augmentation
- PTP
Mechanism of facilitation
Increased probability of quantum release (due to Ca accumulation)
Mechanism of depression
Depletion of vesicles, accumulation of presynaptic Ca
Mechanism of augmentation
Increased probability of quantum release
What is PTP?
tetanus for longer period of time -> depression -> PTP (bounce to positive)
Mechanism of PTP
Increased NT release (due to increased size of RRP), increased baseline NT release
what causes mPs?
PTP
3 stages of LTP
- Induction
- Expression
- Maintenance
Postsynaptic factors underlying LTP
- Ca entry through NMDA-R
2. Activation of silent AMPA-R
Evidence for NMDA-R role in LTP
- Blocking NMDA-R during induction prevents LTP
2. Doogie mouse (overexpressed NMDA-R) is better at learning and memory
Mechanism of AMPA-R response during LTP
Ca ⇒ bind to calmodulin (CaM) ⇒ activate calcium-calmodulin-dependent protein kinase II (CaMKII) ⇒ autophosphorylate ⇒ {P} AMPA-Rs already in membrane (↑ conductance) + facilitate mobilization of AMPA-R to membrane
Very long-term LTP is dependent on…
- NMDA-R for induction
- Epigenetic effects
- Ca-induced Ca release
Mechanism of LTD
○ Ca entry through NMDA-R (large increase in [Ca]) ⇒ LTP (local response)
○ Depolarization spreads to nearby synapses ⇒ Ca entry through v-gated Ca channels (small increase in [Ca]) ⇒ LTD
