Synaptic plasticity as mechanism for learning and memory p.I

Question 1

What is LTP?

(4 marks)

Answer 1

• Long lasting increase in synaptic strength induced by persistent patterns
• Need certain threshold of activity before LTP synapse seen in brain
• Input specific
• Shows associativity

Question 2

What critieria were to be met in order to prove that synaptic plasticity is the basis of LTM?

(2 marks)

Answer 2

• Memory of prior experience is mediated by reactivation of memory traces who’s basis was change in synaptic efficiency
• Synaptic plasticity was both necessary and sufficient for LTM

Question 3

What is necessity?

Answer 3

• Things that can block LTP should also be able to block learning

Question 4

What is sufficiency?

Answer 4

• Inducing plasticity at a discrete set of synapses should produce new memory

Question 5

How is the NMDA receptor implicated in long term memory?

(3 marks)

Answer 5

• Train animal in morris water maze and give one group NMDAR anatagonist AP5
• Animals with anatgonist weren’t able to find platform a week later
• AP5 blocks long term hippocampal memories

Question 6

What is a problem encountered when testing necessity?

Answer 6

Need to be able to block plasticity and nothing else

Question 7

In what events does NMDAR allow permeation of Ca²⁺ and other cations?

Answer 7

1. Neurotransmitter is bound followig release of glutamate from pre-synaptic terminal
2. Post-synaptic membrane is sufficiently depolarised to allow for injection of Mg²⁺ ions which at near resting membrane potenital block ion pore of NMDARs