Lecture 5 - Models for Studying L & M

Question 1

What kind of stimuli were paired by Pavlov?

Answer 1

Paired an unconditioned stimulus(food) with a neutral stimulus (bell)

Question 2

What is the unconditioned stimulus and the response in Aplysia?

Answer 2

Touch siphon - gill withdrawal

Question 3

How do you sensitise Aplysia?

Answer 3

Pair electric shock to touch on siphon will give you a very strong gill withdrawal

Question 4

Hows many neurons does Aplysia have?

Answer 4

Around 20000

Question 5

Why is Aplysia used as a model?

Answer 5

Cell bodies of neurons are 1mm in diameter so injection is easy

Question 6

How can you change the term of the learned behaviour in Aplysia?

Answer 6

Repeated pairing (more shocks in a row on more days)

Question 7

What is the neural circuitry of the tail shock?

Answer 7

Sensory neuron synapses on modulatory interneuron which then synapses (with serotonin) onto the axon of the sensory neuron innervating the siphon.

Question 8

What happens as you touch the siphon more and more with out a shock?

Answer 8

The sensory neuron from it releases less and less glutamate onto the interneuron and motor neuron of the gill

Question 9

How does the shock change the neural circuitry?

Answer 9

Modulatory interneuron synapses and releases serotonin onto the axons of the sensory neuron from the siphon, increasing the amount of glutamate being released from that onto the interneuron and motor neuron of the gill. (presynaptic facilitation)

Question 10

How does the modulatory interneuron cause presynaptic facilitation?

Answer 10

The serotonin increases PKA by making 5-HT bind to the PKA receptors leading to more NT release

Question 11

Who used Aplysia as a model?

Answer 11

Candell

Question 12

Why is the fly a good model?

Answer 12

Allows you to change what, where and when proteins are expressed

Question 13

What experiment did Dudai et al (1976) do with flies?

Answer 13

Taught to avoid an odor (OCT) by giving them an electric shock when exposed to it.
When offered the choice of the shock odor and an odor they didn’t know, most went to the latter (MCH)

Question 14

What form of learning do the Aplysia and flies show?

Answer 14

Implicit learning

Question 15

What is dunce?

Answer 15

The first memory mutant fly found

Question 16

What is dunce’s mutation in?

Answer 16

cAMP phosphodiesterase (degrades cAMP)

Question 17

What is rutabaga?

Answer 17

Second memory mutant found

Question 18

What is rutabaga’s mutation in?

Answer 18

Adenylyl cyclase (forms cAMP)

Question 19

What were the results of Dudai’s odor experiment and what does this suggest?

Answer 19

dunce and rutabaga had a memory performance of about 40% wheras WT was 90%.
Double mutant was 17%.
cAMP important in learning.

Question 20

What did cued fear conditioning in rats involve?

Answer 20

Sound played before electric shock, rats froze when they heard the sound.
Could measure several things like freezing time and blood pressure

Question 21

What is contextual learning?

Answer 21

Changing the environment but giving the same negative stimulus - the rat animal will know next time the environment changes and freeze

Question 22

What is fear extinction?

Answer 22

Giving the conditioned neutral stimulus over and over with out the negative stimulus (eg shock) so the animal forgets

Question 23

What parts of the brain are involved in cued fear conditioning?

Answer 23

amygdala

Question 24

What parts of the brain are involved in contextual conditioning?

Answer 24

amygdala and hippocampus

Question 25

What are two good examples of operant conditioning?

Answer 25

Skinner box and Pavlov’s dogs

Question 26

How can you test implicit memory and some elements of explicit memory?

Answer 26

Morris water maze

Question 27

Features of Morris water maze

Answer 27

• 3 visual cues around the room

- Small platform in opaque water

Question 28

What things are measured in the morris water maze?

Answer 28

• Latency - time taken to get to platform
• Platform crossings - around the platform
• Time spent in quadrants - see if its correct

Question 29

What experiment did Bourtchuladze et al (1994) do?

Answer 29

• Had mice with disruption in gene encoding CREB (a TF activated by cAMP and Ca)
• Did spatial learning in morris water maze

Question 30

What were the results of Bourtchuladze et al (1994)’s experiment?

Answer 30

CREB mutants show a significantly decreased memory

Question 31

What were the controls in Bourtchuladze’s experiment to check the mutants had the same sensory and motor functions?

Answer 31

• Mutants and WT exposed to unpleasant stimuli, flinching, jumping and vocalising measured

Question 32

What did Bourtchuladze show with intensive training?

Answer 32

Showed that if the mutants were trained much harder they were just as effective as the controls