LEARNING & MEMORY

Question 1

What is amnesia, and how is it commonly categorised?

Answer 1

• Amnesia = memory deficits often experienced by neuropsychological patients.
• retrograde amnesia: can’t remember old memories
• anterograde amnesia: can’t form new long-term memories
• Patients often exhibit partial retrograde amnesia, & anterograde amnesia is rarely isolated

Question 2

what is an example case of intergrade amnesia?

Answer 2

• H.M
• bilateral removal of medical temporal lobe > inc: hippocampus, amygdala & cortex > treatment for severe epilepsy
• retrograde amnesia > approx. 10 yrs, complete anterograde amnesia
• hippocampus & nearby cortex involved in consolidating memories

Question 3

Can you explain dissociations in memory observed in amnesic patients?

Answer 3

• Amnesic patients > esp those struggle w/ new long-term memories (anterograde amnesia) but retain other learning types = led to identifying declarative (explicit) inc: verbalise memories and non-declarative (implicit> skills, automatic responses) memory systems.

Question 4

What role does the hippocampus play in memory?

Answer 4

• located > medial temporal lobe = crucial for memory formation
• Lesions in hippocampus, specifically in areas like CA1, = anterograde amnesia
• involved in relational learning > impacting declarative memory

Question 5

what is anoxia?

Answer 5

• complete deprivation of oxygen
• leads to specific hippocampus damage > esp CA1 > extent of anterograde amnesia grows w/ increase damage in surrounding areas

Question 6

what is emotional conditioning?

Answer 6

• process > which an individual associates specific emotions or feelings with particular stimuli or situations
• involves the pairing of a neutral stimulus w/ an emotional response = learned association between the two.
• e.g. Pavlov classical conditioning
• S.M > bilateral hippocampus damage > fear conditioning but didn’t remember experiment < no episodic declarative memory

Question 7

what is the difference between episodic and semantic memory?

Answer 7

• Episodic memory > personal experiences w/ a temporal context
• semantic memory > general knowledge & facts w/o personal or temporal specifics
• Episodic memories are tied to specific events & evoke a sense of self, whereas semantic memories are impersonal & lack the same temporal consciousness
• some patients show evidence of new factual learning w/ little or no episodic recall = distinction between hippocampus and limbic cortex?

Question 8

can fMRI evidence show hippocampus might be involved in memory retrieval?

Answer 8

• Wagner et al > subsequent memory task
• record activity during encoding > divide trials according to recall success in subsequent surprise memory test
• record where brain was active in recall

Question 9

what is spatial memory?

Answer 9

• involves encoding the relationships between landmarks
• hippocampus esp large in foraging corvids that cache food & large in London cab drivers = formation of spatial memory dependant on hippocampus as brain region

Question 10

what is the cellular basis of memory?

Answer 10

• involves long-term potentiation, synaptic changes, neurotransmitters like glutamate, NMDA receptors, & structural alterations in neuronal circuits > particularly in regions like the hippocampus
• Memory formation & storage inc> growth of new synapses & changes in synaptic plasticity across distributed brain networks

Question 11

What is Hebb’s law, and how does it relate to memory?

Answer 11

• suggests strengthened connections between neurons when their activity correlates > providing a neural basis for learning, particularly classical conditioning
• “Cells that fire together wire together.”

Question 12

How does long-term potentiation (LTP) relate to memory?

Answer 12

• LTP > high-frequency electrical stimuli strengthen connections between neurons = a neural mechanism supporting Hebbian learning
• LTP > in hippocampus = strengthening of synaptic connections = contributing to the formation of long-term memories
• to investigate LTP = measure post synaptic potential before & after the pre & post synaptic cells have been made to fire at the same time

Question 13

How has the relationship between LTP and memory been demonstrated?

Answer 13

• Blocking LTP using NMDA antagonists or genetic interventions = impairs spatial learning > seen in the Morris water maze experiment = demonstrating the link between LTP and memory.

Question 14

what are specific conditions which allow NMDA receptors to open?

Answer 14

• post synaptic cell has to be activated > will kick out magnesium ion
• • presynaptic cell has to be activated > releases glutamate = activate NMDA receptor > pre & post need to be active same time for NDMA to allow calcium to initiate process of LTP = strengthen synaptic connections

Question 15

what are the properties of Long-Term Potentiation (LTP)?

Answer 15

• input specify > arises only at specific synapses > occurs selectively in the synapses that have been activated, rather than affecting all synapses on a neuron equally
• associativity > other active synapses can also be strengthened > LTP can be induced more effectively if a weak stimulus is paired with a strong one