L9 - memory Flashcards
memory as reconstruction
pieced together from small pieces
modal model of memory components
STM = RAM, restricted capacity
LTM = hard disk, infinite capacity
processes in modal model
encoding, storage, retrieval, recall
keeping in memory: attention, rehearsal, recall
otherwise: decay, interference
memory span/duration
Modal model:
sensory register - seconds
STM - indefinitely if rehearsed/18-30s
LTM - indefinitely
chunking
individual pieces of information bound to create meaningful whole
working memory
phonological loop, visuospatial, sketchpad, central executive (control/ regulation of processes, directs focus)
HM’s spared and impaired abilities
spared: procedural, semantic, priming, conditioning, implicit memory tasks
impaired: episodic, recognition of recent objects/places, explicit memory tasks
implicit vs explicit memory/paradigm
study item - images
test item - when image revealed gradually, HM could recognise much earlier than if never seen before (implicit) but states that he has not (explicit)
declarative-nondeclarative taxonomy & brain structures
declarative: episodic & semantic (medial temporal lobe in hippocampus)
nondeclarative:
procedural - stratium, motor cortex, cerebellum
priming - neocortex
conditioning - amygdala, cerebellum
non-associative learning - reflex pathway
memory definition
ability to use or revive information previously encoded/processed
biological: every change in neural connectivity
memory as quale & consequences
never directly observed (problem of measurement) - existence is inferred from behaviour
does not exist physically but likely arising from brain activity patterns
understanding requires holistic perspective, related to hard question
synaptic plasticity
change in connection between neurons due to experience, neurobiological basis of learning
cortical plasticity
change in cortical organisation in response to changing demands or brain injury, eg auditory & tactile stimuli recruiting more processing resources after 2 weeks of visual deprivation
Ribot gradient/law of regression
progress of amnesia follows line of least resistance (organisation), ie least consolidated
see retrograde amnesia gradient - most recent memories before amnesia induction exponentially more likely to be forgotten
perseveration-consolidation hypothesis
memories labile after acquisition, permanently consolidated over time (unidirectional process)
disruption to sonsolidation impairs memory formation
synaptic consolidation
learning leads to change in connections between neurons, modifications unstable, need to stabilise to transfer to long-term memory
systems consolidation
certain (eg episodic) memories initially require hippocampus, expression gradually involve it less & frontal areas more
models of systems consolidation
standard model: neocortex regions linked to hippocampus which connects them, cortical connection strengthens as hippocampal connection disappears
extended standard model: prefrontal cortex connects both regions
multiple trace model: links both within neocortex and between neocortex & hippocampus regions
Hebbian learning
principle of associative learning
recurrent connections among neurons of cell assembly keep pattern of activity active on its own for a while after experience (STM)
recurrent activity eventually leads to changes in synapse of cell assembly, pattern can be recreated (structural modification = LTM)
long-term potentiation
HFS/tetanic stimulation of neuron results in long-lasting strengthening of synapting connection
spine size increases, more post-synaptic glutamate receptors so more likely to fire
temporal gradient in amnesia
HM: temporally graded retrograde amnesia for episodic memory & dense anterograde episodic amnesia
hippocampal lesions only impair memory of contextual fear conditioning when applied up to 28 days after conditioning
memory schema
schema: active organisation of past reactions
script
memory structure encoding general knowledge of situation-action routines
memory reconsolidation
every time memory is recalled it becomes active again - unstable, succeptible to change/deletion
prediction error
negative prediction error - expecting shock but not receiving one
positive prediction error - expecting no shock but getting one
fear reduced if reconsolidation interferred with only if there is prediction error
flashbulb memories
memory for circumstances in which one learned of public event (reception memory not event memory)
iconic memory
estimated 500ms (location)
identity memory decays slower
Brown-Peterson paradigm, duration of short-term memory
distraction technique: presented 3 letter nonsense syllable, asked to count backwards in three starting from random number, estimate 18s
retroactive changes to memory
ommission
rationalisation
transformation (unfamiliar to familiar)
forms of forgetting long term episodic memory
erasure/storage failure/consolidation impairment
retrieval failure
memory disruption/interference/trace decay
forgetting curve
logarithmic decay of most episodic LTM
law of disuse/trace decay theory
if connection not made between situation and response, connection’s strength is decreased (passive trace decay)
new law of disuse
storage strength not reduced but retrieval strength does
active decay
organised removal of AMPAR from synapse - forgetting needed to learn new things
proactive & retroactive interference
proactive: old memory interferes with new
retroactive: new memory interferes with old
availability vs accessibility
forgetting never proved, we only know memory less accessible, not necessarily unavailable
encoding specificity principle
likelihood of recall depends on how similar encoding and retrieval situations (contexts) are
transfer appropriate processing
better recall if processes engaged in encoding are appropriate for retrieval tas
levels of processing
shallow - how it looks or sounds
deep - significance & meaning
hyperthymesia
extremely detailed autobiographical memory (AJ)
constant recollections, cannot focus on new info & standardised tests
memory disorder from defective prefrontal cortical circuits
