Memory introduction

Question 1

HM impairments

Answer 1

Spared: IQ, perception, reasoning, abstract thinking, priming and motivation. Non-declarative memory (memory not available for conscious inspection) spared.

Severe amnesia.

Question 2

HM types of amnesia and severity

Answer 2

Anterograde amnesia: severely impaired.
Retrograde amnesia: temporal gradient (loss of recent memories, but preserved childhood memories).

Intact STM but cannot transfer STM into robust LTM.

Question 3

Korsakoff syndrome causes

Answer 3

Thiamine deficiency (vitamin B1) from alcohol. Damage to diencephalon (especially mamillary bodies and thalamus).

Question 4

Korsakoff syndrome symptoms

Answer 4

Lack insight into their conditions. Confabulation (false memories). Some execute dysfunction associated with frontal lobe dysfunction.

Question 5

Alzheimer’s disease anatomy

Answer 5

1. Amygloid plaques: clumps of protein fragments outside of brain’s nerve cells.
2. Neurofibrillary tangles: twisted strands of another protein inside brain cells.
3. Plaques and tangles first seen in transrhinal region.
4. Neurodegeneration in MTL predominantly HC and then spreads.

Question 6

Alzheimer’s disease symptoms

Answer 6

Progressive decline in cognitive function. Recent memory affected first, remote memory affected later.

Question 7

Delay-Brion circuit

Answer 7

A proposed memory circuit in primate brain (includes MTL and diencephalon.

Question 8

Consolidation theory

Answer 8

1. Info is initially registered in neocortex and is bound into a memory trace.
2. Long-term systems consolidation: in early stages depends upon HC for storage and retrieval.
3. Contribution of HC diminishes with time until neocortex alone is capable of sustaining permanent memory trace.

Question 9

Challenges to consolidation theory

Answer 9

1. Impossible to test the gradient of retrograde amnesia. We don’t know what proportion of prior memories retained.
2. How long does consolidation take? Seems to range from seconds to decades.

Question 10

Multiple trace theory

Answer 10

HC plays a role in the retrieval of autobiographical memories throughout a person’s life.

Memory retrieval establishes traces between HC and NC that support memories and retrieval (often remembered memories will ahve more traces).

Question 11

Standard model vs. multiple-trace theory

Answer 11

1. Spared remote memory following partial HC damage: standard model attributes it to completed consolidation; multiple-trace model attributes it to the fact that older memories retrieved more and enough of these distributed traces may survive the sub-total lesion to support memory.
2. Hippocampus: standard model argues that HC needed for both episodic and semantic; multiple-trace model argues that there are dissociations (autobiographical far more affected than semantic).
3. Gradients to retrograde amnesia: standard model argues that there are always gradients to retrograde amnesia; multiple-trace theory points to flat/absent gradients after complete HC lesions (without HC, no traces can remain to support autobiographical memory retrieval).

Question 12

Habituation neural mechanism

Answer 12

Modification in strength of connections. Weaker EPSPs due to modification of presynaptic terminal (fewer packets of neurotransmitters released by each action potential).

Longer-term habituation due to inactivation of connections/structural changes.

Question 13

Sensitisation description

Answer 13

Increase in synaptic strength. Learning about noxious stimuli (altered response to another noxious stimulus; in habituation same stimulus).

Question 14

Heterosynaptic vs. homosynaptic

Answer 14

Habituation is homosynaptic (same pathways involved.
Sensitisation is heterosynaptic (additional pathways and modulatory neurons).

Question 15

2 types of post-synaptic receptors

Answer 15

1. Ionotropic receptors: ion-gated.
2. Metabotropic receptors: activate second messenger systems. Extracellular signal brought into cells - amplified and prolonged.

Question 16

Short-term sensitisation mechanisms

Answer 16

Heterosynpatic facilitation. Transmitter vesicle mobilisation and release. Close k+ channels (prolongs action potentials).

Question 17

Long-term sensitisation mechanisms

Answer 17

Regulation of protein synthesis and growth. CREB initiates new synaptic growth.

Question 18

Rules of classical conditioning

Answer 18

1. Temporal contiguity (CS precedes US).
2. Contingency (CS predicts US).

Question 19

Which area is involved in eye-blink classical conditioning?

Answer 19

Cerebellum - not HC.

Question 20

Who is impaired at perceptuo-motor skill learning (serial reaction time task)?

Answer 20

Parkinsonian and cerebellar degeneration patients (amnesic patients intact).

Question 21

MTL declarative memory system theory

Answer 21

Declarative: memory can be brought to mind as a proposition or an image.
Non-declarative: implicit acquisition of info.

Question 22

Non-declarative challenges to MTL declarative system theory

Answer 22

HC patients (Graham et al., 2006): intact perceptual learning for faces but disrupted perceptual learning for scenes. Inconsistent with idea that MTL plays no role in ‘non-declarative’ perceptual learning.

Question 23

Concurrent discrimination learning ‘habit learning’

Answer 23

Impaired after lesions to perirhinal cortex lesions in macaques. So-called non-declarative memory task being impaired by MTL lesions.