Learning & memory II

Question 1

stages of memory>

Answer 1

• sensory input> sensory memory (represented in terms of N); unattended info lost)
• sensory memory ATTENDED to, converted> STM
• STM rehearsed, can be encoded >LTM

Question 2

Short term memory (proposed model)>

Answer 2

• involves persistenent electrical activity in neurons (rathe than structual changes to synapses)
  >i.e. STM stored in group of neurones, firing passive info around, rather than a physical structural change in connections between neurones

Question 3

Evidence for Short term memory (proposed model)>

Answer 3

• magnetic/electrical stimulation of parietal cortex can ERASE visual STM in humans
• salient info may then be coded>LTM (by causing structural changes to the synapses)

Question 4

synaptic plasticity=

Answer 4

learning is achieved in brain by modification of transmission across synapses

Question 5

Synaptic plasticity: Hebb rule> (Hebb, 1949)

Answer 5

• if post-SM active at same time as Pre-SM then synapse will be STRENGTHENED

Question 6

NDMA Gluatmate receptor & Ca2+> process

Answer 6

1) NDMA channel is plugged by Mg2+
2) Glutamate can bind but Ca2+ cannot enter Ca2+ channel due to Mg2+
>we want to open this neurone as it is Neurone B (from sound of bell)
3) Depolarisation of membrane occurs due to Neurone A
4) this evicts Mg2+ & unblocks channel
5) Ca2+ can now enter

Question 7

What happens when more NMDA receptors are working?>

Answer 7

• can be more Ca2+ in receiving neurone
• can cause more AMPA receptors to form
• thus, more Ca2+ can be taken in
• creates a stronger connection between neurone B & this receiving neurone

Question 8

Role of hippocampus in memory>

Answer 8

• may be involved in consolidation of STM> LTM traces in cerebral cortex
  -H receives info from & sends info> sensory & motor
  association cortexes & subcortical structures such as
  basal ganglia & amygdala
  -Damage to H impairs ability to lay down NEW
  declarative memories (anterograde amnesia)

Question 9

H.M> summary>

Answer 9

• In1953, to treat epilepsy
• bilateral medial temporal lobectomy performed on him
• removed most of hippocampus, amygdala, & adjacent cortex

Question 10

H.M> what remained intact?>

Answer 10

• LTM & STM
• ability to learn new sensorimotor skills
• ability to form classical conditioning associations

Question 11

H.M> What was the damage post-surgery?>

Answer 11

• H.M had severe anterograde amnesia
• unable to form long-term declarative memories
• constant state was like “waking from a dream”

Question 12

characteristics of alzheimers>

Answer 12

• First lesions: appear in poorly myelinated neurones in areas related to memory & learning (e.g. hippocampus)
• increased rate of Atrophy (especially in vulnerable regions like H)
• STM & long-term declarative memory affected early
• Non-declarative implicit memory can also be affected
• individual pattern of impaired function correlates with structure or functional brain integrity

Question 13

Alzheimers & music>

Answer 13

Brain imaging shows:
- light up of ‘supplementary motor area’ which is associated with familiar music
- demonstrates memory of liking the music
- even when music played backwards

Question 14

Dementia & hearing>

Answer 14

• individuals with moderate hearing loss can 3x risk of developing dementia in later life (if untreated)
• if all hearing loss was treated, nearly 1/10 cases of dementia could be eliminated