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Memory and consciousness
Human verbal and visual memory; awareness of memory
Aim Learning
unconscious motor learning conditioning
conscious memory of place
Biology of Memory neural “substrate”
Self v non self awareness
Types of learning Perceptual learning
recognise stimuli you have seen before Motor learning Stimulus-response learning
classical conditioning instrumental (=operant) conditioning
Relational learning episodic spatial
First: motor learning and the cerebellum
Motor learning
Cerebellum
Vestibuloocular reflex VO reflex to stabilize image on retina
when head moves eyeball muscles rotate eye to
compensate no sensory feedback gain has to be exactly 1
Control of VO reflex
Inf Olive
Purk cellgain = E/H = -
hair cell vestibular nucleus optic motor neuron
accessory optic tract
VO gain need Cerebellum
prism left on
prism on
prism off
- -x- - intact
no cerebellum
cats rotated on platform in dark
Control of VO reflex without cerebellum, cannot adapt adaptation during aging and disease
Types of learning Perceptual learning
recognise stimuli you have seen before Motor learning Stimulus-response learning
classical conditioning instrumental (=operant) conditioning
Relational learning episodic spatial
Next: one trial classical conditioning
Classical conditioning food - bell
Pavlovian fear conditioning
CS conditional stimulus US
unconditional stimulus noxious stimulus – eg electric shock
learnt fear response autonomic NS; eyes dilate, blood
pressure rises, heart rate up; hormonal response
Single trial last for years
Amygdala initial stimulus associated with high
levels of adrenaline and corticosterone NMDA receptors in amygdala required
for fear learning – role for LTP
NMDA antagonists / GluR knockoutsprevent acquisition of learning
Consolidation fear conditioning, then ECS
(electroconvulsive shock)
ECS soon after, memory never formed ECS after 24hr, memory fixed
requires protein synthesis soon after stimulus
Generic feature of memories
ReConsolidation fear conditioning, then ECS
ECS soon after, memory never formed ECS after 24hr, memory fixed ECS after reactivating memory,
memory lost requires NMDA receptors and protein
synthesis soon after reactivation stimulus
Long / short term memory STM requires protein synthesis
amygdala Aplysia Honeybee Fruityfly hippocampus
• relational memory
Let’s try it…
STM test
Cortex activity in learning word list
difference in memory effect
Short term memory different sensory
modalities are associated with different areas of the cortex during STM
STM is distributed
Types of learning Perceptual learning
recognise stimuli you have seen before Motor learning Stimulus-response learning
classical conditioning instrumental (=operant) conditioning
Relational learning episodic spatial
Now on to: Relational learning
Amnesia retrograde amnesia
inability to remember something which happened before brain damage
anterograde amnesia Korsakoff’s syndrome – alcohol abuse cannot form new memories tell a fable when asked for recent
events (rather than say don’t remember)
HM hippocampus removed bilaterally remember sentences by rehearsal learn motor skills recall old memories do mental arithmetic
cannot identify by name new people
cannot recognise surroundings
Hippocampus is not location of long term memory
HM would not know how to dress himself
not location of short term memory could not carry out a conversation
site for consolidation of memory
HC active in learning areas of brain which correlate with
rehearsal - learning list of words PET scan while playing word list test words learnt correlate
hippocampus
This leads to: declarative memories
explicitly available to conscious recall as facts, events or specific stimuli (=explicit M)
maybe verbal (as in declare) non-verbal – e.g. as video recall
non-declarative memories not necessarily conscious =implicit M
Hippocampal organisation RB stroke – hippocampus has high
NMDA receptors and very sensitive to ischaemia
amnesia lost CA1 neurons of hippocampus
CA1 CA1
HC Place cells taxi drivers
enlarged CA1 region Rat place cells Induce LTP in
CA1/CA3 neurons → new place cells
CA1 conditional NMDA knockout – longer to learn Morris water maze rat running in
triangular path
Summary so far amygdala : Pavlovian fear conditioning
short / long term memory reconsolidation
hippocampus crucial to memory cognitive maps of the environment consolidation phase
clinical animal models (CA1, CA3?, LTP)
Next: where do we Find LTM ?
Lashley rat exploration
Cortex as I/O of Hc
Summary so far amygdala : Pavlovian fear conditioning
short / long term memory reconsolidation
hippocampus crucial to memory cognitive maps of the environment consolidation phase
STM associated with cortex does not require hippocampus
Finally – memories in the future?
Prospective memory
imagining episodes in the futureDoes this look familiar?
Frontal regions for “self” DB, amnesiac who lost experience of
own past but not non personal past
Lesion data ventromedial frontal damage → lossof personal future time perspective
dorsolateral frontal damage
non-frontal damage.
fMRI Data Big difference
between Clinton/self
Small difference between future/past
Summary to end amygdala : Pavlovian fear conditioning
short / long term memory reconsolidation
hippocampus crucial to memory cognitive maps of the environment consolidation phase
STM associated with cortex does not require hippocampus
frontal region for prospective memory
Happy Christmas !!