Learning and Memory 1

Question 1

Long term potentiation (LTP) -

Answer 1

mechanism underlying synaptic strengthening
Hippocampus - shape and anatomy means pathways can be easily distinguished and recorded from electrophysiologically

Temporal: Summation of inputs reaches a stimulus threshold that leads to the induction of LTP. e.g. Repetitive stimulation (HFS)

Associative: simultaneous stimulation of a strong and weak pathway will induce LTP at both pathways. (Spatial summation)
Coincidence detection
“Cells that fire together wire together”

Question 2

Animal Experiments

Answer 2

you put the rat in there to swim and theres a hidden platform and they have to try and find the platform. period of acquisition over training before they find the trial with no difficulty - will swim straight to the platform

Question 3

Role of NMDA in LTP and learning

Answer 3

Glutamate release onto inactive cell
	(membrane at resting potential) 
AMPA receptor activated to create EPSP
NMDA receptor blocked by Mg2+ ion 
Depolarization from AMPA activation
not sufficient to expel Mg2+

Glutamate release onto an active cell
	(membrane depolarized)
AMPA receptor activated
Mg2+ block on NMDA receptor relieved
Na+ through AMPA and NMDA channels
Ca2+ through NMDA channel

Question 4

CaMKII

Answer 4

Ca2+ entry through the NMDA receptor leads to activation of:
Calcium calmodulin-dependent protein kinase II (CaMKII)
CaMKII has autocatalytic activity - becomes phosphorylated
When phosphorylated is constitutively active - no longer requires Ca2+

Question 5

Enhanced memory and LTP

Answer 5

animal studies show that you can

put mice into a cage filled with environmental enrichment (e.g. a lot better than normal cages lots of toys etc) this environment is sufficient to increase performance in the morris water maze. enriched mice find the platform quicker. Also show greater long term potentiation