learning and memory Flashcards
what is learning
the encoding of a memory, an response to sensory stimulus built upon experience (adaptive or maladaptive)
a novel association, internal stimulus, with beneficial outpu
what is memory
storage of experience for future response to stimulis, short term memory: small capacity (7 words, for 30 seconds)
working memory
long term memory (large capacity- life experiences, long duration for lifespan)
short term memory
accessible to working memory but not immediately attended to, subset of working memory (likely sensory modality specific
working memory
central executive ( prefrontal cortex)
Phonological loop (Brocas and wernikes)
Visuospatial sketch pad (occipital lobe)
Attention controller Episodic buffer (patrietal lobe)
long term memory
Declaritive learning (language based): in medial temporal and diencephalon
Episodic memory: timing of events
Semantic learning facts
non declaritive learning (motor based):
Procedural memory (skilled habits in basal ganglia)
Priming (neocortex)
simple classical condiotioning (amygdala and cerebellum)
Habituation (sensitization, reflex paths)
declarative memory system
hippocampus is the big star
start in cortexthen hippocampus and fornix, (add amygdala if emotion) and then to mammillary bodies to thalamus and basal forebrain and then back to cortex
fear memory
traumatic event–> short term memory–> longterm memory –> altered threat memory–> safety memory
most important is the amygdala (input from thalamus, cortex, hypothalamus)
then projects to PAG and hypothalamus
mechanisms of learning and memory
Molecular: LTP and LTD
Cellular: fire together wire together
Systems: consolidation and reconsolidating
molecular plasticity (FAST)
time scale= secods to hours
Dependent upon stimulation frequency
Key players : glutamate receptors (AMPA and NMDA) and Ca
long term potentiation
post synaptic neuron becomes more sensitive
high frequency stimulation–> NMDA receptor activation removal of Mg2 block–> large intracellular Ca–> Ca MKII activation–> recruitment of more AMPA receptors from intracellular stores to synaptic membrane
long term depression
low frequency stimulation
Small increases in Ca, calcinuerin and protein phosphatase 1 activation, removal of AMPA receptors
Cellular plasticity
Slow , hours
Gene transcription dependent, structural changes in neural connections, spine plasticity, branch plasticity, permanent change in cell state
brain region connectivity
mastery of motor skill takes days
learning induced autonomy of sensory motor systems
release of cognitive control
learning to ride a bike takes focus at first but then its easy (cingulate and frontal)
sleep and memory
consolidation
deep sleep during s3 and s4
Sleep deprivation/disturbance:
Acute: hippocampal encoding deficit, short term memroy impaired
Chronic: amydala reactivity increased, elevated waste, including B-amyloid, increased inflammation, risk of neurodegenerative disease
memory reconsolidation
reactivation of memories, mental practice, eye witness accounts, possible route to modify psychiatric disorders through therapy
