Learning and Memory

Question 1

Define the components of Hebbian’s theory of learning

Answer 1

Associative learning: as cells fire simultaneously they increase their synaptic associations. This results in networks of cells which are synaptically linked.

Habituation: decrease in response and NT release with repeated stimulus

Sensitisation: increase in response with repeated stimulation (mediated by an interneuron)

Question 2

Describe short term memory

Answer 2

Brief memory (seconds) either from an external stimulus or retrieval from long term memory:

• easily displaced by another stimulus
• can be extended into working memory by repetition in a phonic loop

Question 3

Describe working memory

Answer 3

Maintenance and integration of information in an active state for a brief time to achieve a short-term task or goal:

• mix of short and/or retrieved long term memory
• when task is over, can be encoded into long term memory or left to lapse

Question 4

Describe long term memory

Answer 4

Acquisition and retrieval of information over long periods.

Declarative memory (conscious):

• semantics (language/facts) + episodic (experiences/events) = autobiographical memory
• involves medial temporal lobe structures and association areas

Non-declarative memory (unconscious):

• proecedural (skills/habits): basal ganglia and cerebellum
• priming: habituation and sensitisation
• associative learning: classical conditioning (hypothalamus) and emotional responses (amygdala)

Question 5

How would you test short term memory?

Answer 5

Digit span test:

• subject reads an increasing series of numbers repeating it back immediately
• the number of digits that can be repeated back is the digital span
• 6-7 digits is normal
• chunking the information is a strategy often used

Question 6

What are the steps of learning and memory storage?

Answer 6

1. encoding (memory creation)
2. storage (persistence of memory traces)
3. retrieval (memory recovery)
4. consolidation (strengthening of memory traces)

Question 7

Describe declarative memory formation and retrieval in the hippocampus

Answer 7

A series of events are encoded by the hippocampus from integrated sensory information and is linked to their memory location in the cortex and to their correspondance in the hippocampal index.

A retrieval cue can stimulate the hippocampus to link the cue to the memory from its index and direct consciousness to the cortex (before consolidation).

After consolidation, the cue can retrieve the memory directly from the sensory cortex meaning the hippocampus is no longer involved.

Question 8

How can declarative memory consolidation be utilised in the treatment of PTSD

Answer 8

Patient called to re-live the traumatic events leading to their PTSD and then given an adrenergic beta-receptor blocker (eg. propranolol) to block the re-consolidation of memory

Question 9

Describe how the brain consolidates declarative memory into long term memory

Answer 9

Structural changes at the synapse - changes in connectivity in the neuronal networks in the cortex

• increase in presynaptic vesicles, post synaptic receptors or ribosomes
• synapses develop separate zones divided by a cleft
• division of a spine into 2
• growth of synaptic nodes along the length of an axon (creation of more dendritic spines)

Question 10

What structures are responsible for the consolidation of non-declarative memory?

Answer 10

• basal ganglia structures (caudate nucleus, putamen, amygdala): influence memories involving movement and procedural memory
• cerebellum: influence fine motor movement (eg. speech)

Question 11

Damage to which structures can result in anterograde amnesia?

Answer 11

• temporal lobes
• ventral/dorsomedial nuclei of thalamus
• mamillary bodies