Synaptic Plasticity

Question 1

what is synaptic plasticity? why is it important?

Answer 1

• Synaptic plasticity refers to increases or decreases in synaptic strength in response to patterns of synaptic activity
• this is essential for LTP and LTP - essential for learning and memory

Question 2

why is the second PSP greater than the first one? (synaptic facilitiation)

Answer 2

• Synaptic vesicle release is Ca2+ dependent

- Higher levels of Ca2+ -> more vesicle fusion -> more transmitters released

Question 3

why does synaptic facilitation decrease as interval increases?

Answer 3

facilitiation decreases with time because Ca2+ levels recover to normal

Question 4

what is synaptic depression and why does it occur?

Answer 4

• decrease post-synaptic potential
• due to depletion of synaptic vesicle pool
• finite pool of synaptic vesicles with NTs so continuous stimulation -> depletion thus Its decreased as well

Question 5

what is the difference b/w LTP and LTD?

Answer 5

1. Receptor involved 
LTP - NMDA + AMPA 
LTD - AMPA 
2. stimulus 
LTP - HFS
LTD - LFS
3. Ca2+ involved (increased)
LTP - large + fast 
LTD - small + slow 
4. phosphates 
LTP - kinases (P addition)
LTD - phosphates (P removal) 
5. synapses 
LTP - mainly pre-synaptic 
LTD - mainly post-synaptic

Question 6

name few diseases in which synaptic plasticity is involved and affected

Answer 6

1. AD - atrophy of hippocampus thus affecting the LTD + LTP
2. kindling in epilepsy - prolonged LTP -> seizures
3. Drug addiction - VTA-NAc synapse - repeated LTD exposure thus higher doses required to stay high