Memory

Question 1

Key terms
learning
memory
recall
the engram

Answer 1

• acquistion of info
• storage of learned info
• reacquisition of stored info
• physical embodiment of memory

Question 2

Forms/ Types of memory
Independent memory systems?
- procedural/ declarative

Answer 2

-nervous systems perform different types of learning/memory
-procedural vs declarative = implicit vs explicit
p= skills and associations largely unavailable to conscious mind (eg. motor memory)
d= available to conscious mind- can be encoded in symbols and language

Question 3

Memory duration

Answer 3

immediate memory - few seconds
STM - seconds or minutes = working memory here
LTM- days, years

Question 4

Important structures:

• pre-frontal cortex
• hippocampus
• amygdala
• cerebellum

Answer 4

• working
• essential for converting STM to LTM, declarative memory
• multiple, processed sensory inputs(smell), implicit/emotional/ learnt fear
• motor control and learning= procedural, sensorimotor

Question 5

Hippocampus
-lesions?
inputs from where?
outputs via where?

Answer 5

hippocampal lesions (elective or accidental) cause memory loss
stroke in hippocampus = memory loss
-3-layered cortex
-unusual development(due to external surfaces fusing as they curl round)
–>CA fields 1, 2 ,3 ,4
-inputs from entornial cortex and beyond
-outputs to many regions via fornix

Question 6

Mechanisms of memory
reverberating circuits?
hebbian synapse concept?

memory and synaptic plasticity?

LT facilitation/ depression?

Answer 6

long term storage appears to be distributed across the brain(more to do with connections)
Reverberating circuits = memories are disributed over many cells
The hebbian synapse concept - synapses could be changed due to activity being modificable
–>memory and synaptic plasticity
-synaptic strength changes
-facilitation/depression (synapse) –can be ST, Ca++availability/vesicle depression effects efficiency of synapse
(depression=produces lower response with same input)
-Long-term facilitation/depresion

Question 7

Long-term potentiation
what is it?
where?
What is Post-tetanic?

Answer 7

LTP in hippocampal slices(and elsewhere in brain also)

• LTP was looked at between CA1 and CA3, by looking at strengthening response from CA1 (do this via stimulation)
• Post-tetanic LTP = give big stimulus,then smaller one, post-tetanic LTP happens after the high frequency burst

Question 8

What is paired LTP?

Answer 8

-coincident stimulus and depolarisation

2 inputs to same cell at same time= stronger response later on from cell = shows associativity

Question 9

Long term depression?
where?
what is it?

Answer 9

in cerebellum
=its a smaller response than before(weakening the response from the synapse)
(if this was to be an inhibitory synapse= could cause increase in activity overall)

Question 10

Aplysia Californica - gill withdrawal reflex in siphen

shows?

Answer 10

gill withdrawal reflex
Shows: habituation,
short term sensitisation:
– repeated gentle stimulation to siphen causes reduced gill withdrawal = habituation
–but if you pair single tail pinch(aversive) with siphen touch = re-establish siphon reflex
long term sensitisation:
–repeated pairing of siphen touch and tail pich
–LT, non-habituating siphen
classical(Pavlovian) and operant(skinner) conditioning

Question 11

Common themes between LTP, LTD and aplysia

Answer 11

• all require receptor activation(glutamate/ serotonin)
• altered synaptic responsivity
• mediated by second messengers (Ca++/ cAMP)
• require protein phosphorylation changes in early stages
• require protein synthesis for late stages of memory formation (due to need for structural change)
• involve biochemical and structural pre and post-synaptic changes

Question 12

Pathologies affecting memory?
Anterograde amnesia?
Retrograde amnesia?
causes?
Alzheimers?

Answer 12

forgetting allows for more important things to be focused on and remembered
pathological forgetting= amnesia
Anterograde amnesia = problem forming new memories
Retrograde amnesia = problem remembering old memories
can be caused by: head injury, tumour, surgery, ECT
Alzheimers - hippocampal susceptibility
AD brain - senile plaques and tangles
-taxi drivers = better hippocampus study