Lecture 6 - how to store a memory

Question 1

Hebbian learning

Answer 1

A form of activity dependent synaptic plasticity where correlated activation of pre and postsynaptic neurons leads to the strengthening of the connection the two neurons. Cells that fire together, wire together

Question 2

LTP

Answer 2

Synapses can be strengthened by artificial stimulation through LTP. When neurns are artificially stimulated, this causes depolarisation of the membrane which will lead to the unblocking of the neurons ion channels. Calcium influx will lead to LTP induction via downstream changes. This leads to an increase in available receptions and then changes in protein synthesis that can induce long term alterations in the shape and strength of the synapses.

Question 3

How did we show that blocking LTP prevents memory formation?

Answer 3

AP5 (NMDA antagonist) blocks LTP and prevents memory formation, as shown in the water maze experiment where rats are placed in a pool and have to find a solid platform using their memory.

Question 4

how did we show the reversal of LTP produces forgetting

Answer 4

The ability of synapses to keep strength over time depended on PKM. ZIP a PKM inhibitor, is widely used to interfere with the maintenance of acquired memories. This also abolishes long term retention of spatial information. As shown in the shock training of rats in the rotating arena.

Question 5

How did we show learning leads to LTP like changes

Answer 5

Dendrites have spines on them and memory promotes branch specific spine formation. Shown in mouse learning to walk on a moving cylinder. Their motor learning resulted in dendrite spine formation. This spine formation could be blocked using an NMDA antagonist which blocks LTP.