Week 1 - introduction

Question 1

Learning definition

Answer 1

acquisition of an altered behavioural response due to an environmental stimulus

Question 2

What type of learning applies to most learning?

Answer 2

associative learning

Question 3

Memory definition

Answer 3

The processes through which learned information is stored. Memory can be short lasting or long lasting

Question 4

Retrieval definition

Answer 4

A conscious or unconscious process that accesses stored information

Question 5

What are three types of the experimental analysis of memory with examples?

Answer 5

Observations - e.g brain imaging

Loss of function - establishes whether a process is necessary for memory - e.g lesion studies

Gain of function - establishes whether a process is sufficient for memory - e.g Pharmacological activation of a molecule

Question 6

Describe Karl Lashleys 1950 lesion study

Answer 6

Method:
Trained rats on a navigation task
Lesioned every part of the cortex bit by bit, in different orders

Results:
Huge variability in memory ability following rats cortical lesion
There is not one single brain region where all memories are located

Conclusion:
Memory is distributed throughout

Question 7

What is one criticism of Lashleys conclusion

Answer 7

He was considering general memory. However we now know that specific memories are located in specific areas of the brain

Question 8

Strengths and weaknesses of lesion studies

Answer 8

Strengths: Requirement of brain regions for memory can be determined. This will identify the location of stored memory

Weaknesses: : Lesion may affect performance in the behavioural task, preventing
assessment of memory. Lesion may also cause effects in other brain regions.

Question 9

What are strengths and weaknesses of imaging studies

Answer 9

Strengths: Identification of brain regions relevant for memory without inference.

Weaknesses: Studies just observe activity in various brain regions. But, are these
regions really important?

Question 10

Describe the Morris water maze

Answer 10

An animal is submerged in murky water and needs to locate the hidden platforms by using clues inside the room.

Question 11

What is Semons 1921 proposal

Answer 11

Memories are stored as engrams

Engrams are lasting physical changes in brain state and structure that occur in response to an experience

Question 12

What is the hebb postulate?

Answer 12

neurons that fire together wire together

Question 13

Describe the Autophosphorylation proposal of CaMK11q

Answer 13

Lisman (2017) proposed that kinase that can phosphorylate itself could store memory. CaMK11 was discovered a year later that has Autophosphorylation properties and can possibly act as a memory storing molecule.

Question 14

Describe details of hebbian plasticity

Answer 14

Neurons wire together when one is repeatedly and persistently exciting the other

Its not the whole neuron that becomes more excitable when it is wired together with another neuron - it is the specific single connection between that neuron and another neuron

This often involves the LTD of other inputs. So you are essentially biasing the recipients neuron to one input over another

Question 15

What is the cell assembly?

Answer 15

Groups of neurons that are connected through hebbian plasticity to mediate perceptual binding

Our memory system has the ability to complete a pattern based on limited information. Cell assemblies can explain this.

Assemblies (groups of neurons) are activated by a stimulus.
After the stimulus, activity reverberates across the groups.
Hebbian plasticity selectively strengthens recipricol connections between active neurons.
The strengthened connection among the neurons contain the engram.
Partial stimulus activates part of the assembly, which in turn activates the whole assembly (pattern completion)

Question 16

What is the phase sequence?

Answer 16

Sequencing assemblies over time and space into complex percepts

Question 17

Outline Clayton, Bussey and Dickinson’s scrub Jay studies

Answer 17

Scrub jays have sophisticated episodic memory

They hide their worms and nuts and remember exactly where they buried them

They always recover the worms before the nuts because nuts are preserved for longer

If another bird is watching them bury the food, they will come back later when they are no longer watching, and move all their food

Question 18

Outline Kandel’s study on habituation in aplasia sea slugs

Answer 18

aplasia have giant neurons that are easy to clamp and get intraneuron recordings

He discovered habituation

If you squirt water onto the slugs gill it will initially withdraw the gill. If you keep doing it it will stop the gill from withdrawing.

Kandel found that as this happens, the sensory neuron is as electrically active as before, however the motor neuron is no longer active. This suggests that the synapse has weakened.

Question 19

Why is most memory work on mice?

Answer 19

It is mammal - more related to humans

It produces large litters

Short gestation time

Matures quickly

Amenable to genetic engineering: molecular mechanisms can be suppressed or enhanced; cell type markers and activity-dependent markers can be expressed; opto-genetic and chemo-genetic actuators can be expressed; diseases with known genetic causes can be modelled

Question 19

What is Korsakoff syndrome

Answer 19

Patients that were losing episodic memory

Found to be caused by drinking bad alcohol with methanol that caused a lesion in a small part of the brain called the mammillary bodies

This shows that there are some memory centres specific to very specific types of memory

Question 20

What are two subtypes of declarative/explicit memory

Answer 20

semantic

episodic

Question 21

What are two subtypes of non declarative memory

Answer 21

Associative

Non-associative