Lecture 8- Evidence for LTP in animal learning

Question 1

Who first demonstrated LTP in the amygdala in fear conditioning?

Answer 1

Rogan et al 1997

Question 2

How did Rogan et al 1997 demonstrate LTP in the amygdala?

Answer 2

• Put an electrode into the amygdala measuring extracellular field potentials
• Play a tone and couple it with foot shock and train
• See enhanced synaptic response

Question 3

What is inhibitory avoidance learning?

Answer 3

• Have a box half in light half in dark - usually hang in dark.
• Given electric shock in dark
• Test memory next day and none went back in

Question 4

What did Whitlock et al 2006 do with electrodes and mice?

Answer 4

• Put 8 electrodes into hippocampus

- Recorded field potentials when mice shocked

Question 5

What are optogenetic tools?

Answer 5

Getting neurons to express channelrhodopsin -2 (causes depolarisation in response to light pulses by opening sodium channels)

Question 6

How do you make channelrhodopsin-2 (ChR2) inducible?

Answer 6

• One gene cluster with c-fos promoter and tTA
• tTA activates another gene cluster with TRE on it and ChR2
• Only activated by taking away antibiotics (doxycyclin) in the diet of the mouse

Question 7

How did Ramirez et al create false memories?

Answer 7

• Took the mice off Dox in red triangle room so ChR2 expressed in neurons encoding that
• Then put them in a grey square room and gave them footshock but also gave them light
• Light activated red triangle neurons so next time the mouse goes in there it freezes even though it was not shocked there

Question 8

How did Morris et al (1998) show saturation of LTP occluding new memory encoding?

Answer 8

Gave high frequency bursts to mice doing morris water maze, showed very bad memory compared to low frequency or non-stimulated

Question 9

What strange thing happened when Powell knocked out Rab3A?

Answer 9

Had no mfLTP by had normal memory in morris water maze and fear conditioning

Question 10

How has the community rationalised the problem with Rab3A?

Answer 10

Not the only thing that interacts with RIM1a so something compensating

Question 11

What did Sakimura et al (1995) do to correlate LTP and learning?

Answer 11

KO NMDAR function
targetted disruption of NR1 subunit gene in CA1 neurons only
reduction in CA1 LTP = deficiency in spatial learning