Physiological Models Of Learning And Memory Flashcards
Learning and memory
Acquisition, encoding, storage and retrieval of information in the nervous system (Purves et al., 2004)
E.g. knowledge, behaviour, skills, values, preferences, emotional responses
Memory types
Declarative memory
Non-declarative (procedural) memory
Short term (immediate) memory
Working memory
Long term memory
Immediate -> working -> consolidation -> long term
Declarative memory
Consciously accessible and available
E.g. exam memory, remembering facts, figures, word definitions
Non-declarative (procedural) memory
Unconsciously available
Don’t think about it
E.g. muscle memory, driving, tying shoe lace
Short term (immediate) memory
Fractions of seconds
Doesn’t need to be stored
Working memory
Seconds to minutes
Doesn’t need to be stored
Long term memory
Days to years
Forgetting
Essential element
Limited capacity in central nervous system - brain
Training improves retention
Critical for normal functioning
Amnesia
Amnesia
Pathophysiological
Anterograde - losing ability to form new memories e.g. today
Retrograde - losing store of old memories e.g. years ago, already encoded memories
Proposed site for short term memory
Hippocampus - use dependant change in neuronal excitability in the hippocampus
Anterograde amnesia
Proposed site for long term memory
Wider distribution in cortex
Retrograde amnesia
Long-term potentiation
In hippocampus presynaptic neurones release glutamate
Postsynaptic neurones have glutamate receptors
Changes in the postsynaptic neurone behaviour depends upon how they’re stimulated by presynaptic neurone
Massive input - more sensitive and change in excitability
Lasts for a long time
Long-term potentiation: cellular process - small stimulus
Presynaptic cell activated and release glutamate
AMPA receptors activated by glutamate
Allow Na+ into the neurone
Causes depolarisation and postsynaptic activation
Long-term potentiation: cellular process - maximal stimulus
Large amount of glutamate activate NMDA receptors
Loses the block caused by magnesium so glutamate can bind
Ca2+ enters neurone leading to activation of kinase
Triggers change in excitability
Changes sensitivity of AMPA to glutamate and recruits more glutamate receptors
Response is larger
Long-term potentiation: changes in gene activation
Activation of CREB (transcription factor) switch on and off different genes
Changes in production of proteins associated with synaptogenesis, synaptic stabilisation, synaptic strength
Neurogenesis within hippocampus, produce more cells and neurones
Models for memory consolidation: short term memory
Neural pathways associative cortex to hippocampus
Encoding short term memory
Models for memory consolidation: long term memory
Neural pathways back from hippocampus to associative cortex
Longer term storage
