L4- Learning and the Brain

Question 1

What is Prediction Error?

What does it represent?

Answer 1

It is [Actual Outcome - Expected Outcome]

It is the extent to which the organism was unable to predict the correct outcome US (surprise).

It is assumed to drive new learning.

Question 2

How does dopamine influence learning?

Answer 2

Neurons that release dopamine become more active when an animal experiences a reward and a few dopamine neurons respond to punishment.

Question 3

Do dopamine neurons increase their activity when a conditioned stimulus is presented (when an animal is anticipating a reward)?

What does this imply?

Answer 3

Yes, they increase in activity.

They seem to be involved in learning.

Question 4

What is Single Cell Recording?

Answer 4

When you measure activity from just a single cell, rather than measuring activity in the entire brain.

Question 5

What is an action potential?

Answer 5

The change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell.

Question 6

A neuron that is not engaged will not show any activity.

True or False

Why?

Answer 6

False

Even if a neuron is not engaged it will spontaneously fire action potentials at a baseline rate. If they don’t do that they tend to die.

This is why you see dots even with no CS

Question 7

A conditioned animal’s neurons will respond to both the CS and the reward.

True or False

Why?

Answer 7

False

An animal neurons that has been conditioned seems to only respond to the CS (if it has been conditioned to expect a reward after) and not the reward itself.

The dopamine neurons only fire if there is a surprise.

This test was done by Shultz

Question 8

What happens to dopamine neurons during extinction (if the animal is presented with the stimulus but received no reward)?

Answer 8

The neuron goes silent when the animal should have received the reward.

Question 9

Do dopamine neurons respond to reward or prediction error?

Answer 9

Prediction Error

Question 10

In Shultz test, what part of the text is the Associative strength of CS (V) and what part is Prediction Error (λ - V)

Answer 10

Just after CS = (V)

Just after the expected response is Prediction Error = (λ-V)

Question 11

What is Control (Unovershadowing)?

Answer 11

When Phase one of the experiment the CS is not paired with the US and then in phase 2 the second CS is paired with both the first CS and the US.

It delivers a strong CR

Question 12

Is the activity of dopamine neurons consistent with either the Hull-Spence Model or the Rescorla Wagner Model?

Answer 12

Consistent with the Rescorla Wagner Model.

Question 13

What is the catastrophic interference problem of associative and connectionist models?

Answer 13

Most models ‘suffer’ from catastrophic interference (new learning erases old learning)

e.g. model learns A-B association, then learns A-C association, it would forget A-B association entirely.

Humans and animals, on the other hand, remember both A-B and A-C and can both be recalled.

Question 14

What is Synaptic Plasticity?

Answer 14

It is how learning is thought to occur in part.

Synapses between neurons gradually become more efficient at transmitting a neural signal the more they are used.

This happens because the dendrite (receiver of another neuron) creating more receptors that become more efficient at accepting the neurotransmitters)

Question 15

Memories are stored in one part of the brain at a time.

True or False

Why?

Answer 15

False

Memories are stored in multiple parts of the brain at the same time to avoid ‘catastrophic interference’ (completely forgetting information).

Question 16

What is the difference in memory and interference between the Hippocampus and Neocortex?

Answer 16

Hippocampus: Learns quickly, it stores memories temporarily. Because of its rapid synaptic plasticity, it suffers from interference. (learns associations fast, forgets fast)

Neocortex: Memories are gradually acquired in the neocortex, where they are stored permanently. Its synaptic plasticity is slower but more stable. (learns slower, more stable)

Question 17

1. Your memory of ‘where you parked your car today’ is a memory that is stored in which part of the brain?
2. Your memories of what your ‘best parking strategy’ is stored in which part of your brain?

Answer 17

1. Hippocampus
2. Neocortex

Question 18

What is Episodic Memory?

Answer 18

A type of long-term memory that involves conscious recollection of previous experiences together with their context in terms of time, place, associated emotions, etc.​

Remember what, where and when

Question 19

What type of memory will you be unable to form if you damage your Hippocampus?

Answer 19

Episodic

Question 20

What is Procedural Memory?

Answer 20

A type of implicit memory (unconscious memory) and long-term memory which aids the performance of particular types of tasks without conscious awareness of these previous experiences.

Tying shoes, riding a bike, reading, gaming

Question 21

Damage to the Hippocampus will mean you can no longer form procedural memories.

True or False

Answer 21

False

It will only stop you from forming episodic memories

Question 22

1. What is Retrograde Amnesia?
2. What does it negatively affect?

Answer 22

1. Where you forget memories that happened right before the Hippocampus was damaged.
2. Episodic Memory, Autobiographical Memory, Declarative Memory.
   * Newer memories far more likely to be lost than old ones*

Question 23

What were Haist, Gore and Mao (2001) findings on memory when using fMRI scans during their experiment on presenting healthy adults with famous faces from different decades?

Answer 23

That they could recall names of all celebrities equally well regardless of the decade.

However, their hippocampus was most active when presented with recent celebrities.

Faces of celebrities from the past activated the entorhinal cortex.

Memory Structure: Hippocampus -> Entorhinal Cortex -> Neocortex

Question 24

Where are memories stored?

Answer 24

Memories are postulated to be stored in the synapses between neurons that fire simultaneously to recreate the experience.

Question 25

Describe how memories and learning are formed through neurons and synapses.

What is this process called?

Answer 25

An action potential releases a neurotransmitter that is released in the synapse of a neuron that travels to the dendrite of another neuron. If this happens the process will get strengthened because the dendrite will create more receptors that will activate faster.

This is called synaptic plasticity.

Question 26

What is memory consolidation?

What happens during this process?

Answer 26

Newly acquired memories becoming consolidated to be remembered permanently.

During synaptic consolidation, neurons produce proteins that strengthen synaptic transmission. These are whats used to change the receptors and change the ability to respond to other neurons.

Question 27

What is memory reconsolidation theory?

Answer 27

That every time a memory is recalled, the old memory becomes labile (is easily changed) it undergoes re-consolidation.

• For memories to be kept they need new protein synthesis in your neurons so it goes back to a consolidated state.*
• Memories become re-consolidated every time we think of them. They are very fragile and unreliable.*

Question 28

What sort of memories does the amygdala hold?

Answer 28

Fearful memories are stored in the amygdala (fear conditioning depends on an intact amygdala)

Question 29

How might you weaken consolidated memories according to memory reconsolidation theory?

Answer 29

Every time an old memory is brought to the surface, in order to be remembered, the neurons need to produce proteins to strengthen synaptic transmission.

Drugs that inhibit protein synthesis while the memory is being recalled can actually weaken the memory.

Question 30

Explain what is happening in this experiment. What theory is being shown?

Answer 30

Rats were made to fear a certain stimulus, however, the rats were injected with Anisomycin into the amygdala when their fearful memory was recalled. This reduced the fearful response the next time the memory was recalled.

The theory that is being tested was memory reconsolidation theory. It showed that memories are fragile and if synaptic proteins are blocking during memory recall they can be weakened.

Question 31

How might you help individuals with PTSD using memory reconsolidation theory?

Answer 31

You get the individuals to recall their traumatic experiences while giving them synaptic protein inhibitors. This will weaken the memory and make the memory less impactful.

• Disrupt the protein synthesis while the individual is thinking of the memory and it will weaken the memory.*
• In this test, Propranolol is put into the amygdala (where fearful memories are held) and this made the memory less emotional.*

Question 32

Does reducing synaptic proteins during memory recall according to memory reconsolidation theory mean you forget your memories?

Answer 32

No, but it can reduce the impact it has on it and may change it slightly.