cogsci c127: memory

episodic memory

(type of declarative memory) previous experiences of events/objects/places

contextualized (self at center)

semantic memories

(declarative memory) reflects knowledge/facts (e.g. abt ppl/places)

de-contextualized (detached from where they were learned)

explicit memory

allows for conscious recollection of prior experiences and facts. typically verbalizable

implicit memory

allows prior experience to affect behavior without deliberate retrieval or conscious awareness. not expressed verbally but thru performance (e.g. unintentional facilitation or prev learning)

stages of memory

• encoding (all)

• maintenance/storage (all but sensory memory)

• retrieval (long-term memory)

• consolidation (declarative LTM, at least)

mechanisms of memory loss

decay (representation goes away)

interference (representation gets replaced)

sensory memory

sensory info that is immediately accessible but not currently attended

• distinct memory stores for each modality - e.g. auditory (echoic), visual (iconic), tactile (haptic)

• high capacity, short duration (short term)

short-term memory

to go beyond sensory areas and be held online, info has to transition from sensory to ____________

• first place attention can act

working memory

goal-directed maintenance, manipulation, and use of info retained in STM, over seconds to minutes

atkinson & shiffrin’s modal model

proposes serial structure: attention shifts info from sensory memory to STM, then shifts to LTM w rehearsal

proposes single unitary short-term memory store

bradley & hitch’s tripartite model

priming

• you process a stimulus quicker or bring info to mind more readily if you’ve recently seen a related stimulus

perceptual priming

priming within the same modality

longer effects

conceptual priming

priming w same object/concept conveyed in other modality

shorter effects

parieto-occipital regions (esp. right hemisphere)

spatial span impaired by damage to

left premotor and supramarginal gyrus

verbal span impaired by damage to

right frontal, parietal, extrastriata

active while holding spatial info

left interior LPFC

active while holding verbal info

separate STM sub-systems: phonological vs visuospatial

separate short-term memory stores for acoustic info (phonological loop) vs. visual/spatial (visuospatial sketchpad)

central executive arbitrates and coordinates STM subsystems

evidence against STM and LTM being serial

patients emerged w impaired STM but preserved LTM and vice versa

STM-impaired patients showed selectivity in their impairments

separable STM sub-systems: evidence from interference

when holding a word list in mind w an imagery strategy (visual), yoi remember fewer words if you are simultaneously tracking visual movement

if you are using a rehearsal strategy (verbal), you remember fewer words if you are simultaneously repeating nonserse words

selective impairment of perceptual priming

M.S. had right occipital lobe removed, was impaired at perceptual priming task (visual-visual), but preserved conceptual priming (auditory-visual) and recognition memory

amnesiacs show normal perceptual priming but no recollection of words

INFERENCE: priming relies on diff system than episodic recall AND system is tied to relevant perceptual processes

basal ganglia

meditates procedural learning thru trial and error

dopaminergic inputs to BG

signal the extent to which actions lead to outcomes that are better/worse than expected

True

(T/F) error-driven learning can occur without awareness of the specific action-outcome associations that were learned, and develop into complex multi-step habits

weather prediction task

healthy adults show increased basal ganglia activity while learning probabilistic action-outcome associations

patients w damage to the basal ganglia (e.g. Parkinson’s) are impaired at skill-learning tasks like this, but not w implicit/declarative memory

classic (Pavlonian) conditioning

learning to associate a stimulus w an emotionally salient outcome, primarily mediated by amygdala

generalization

associations can be triggered by new stimuli that are similar to the original

delay conditioning

learning associations when stimulus and outcome overlap (amnesics can learn)

trace conditioning

associations when outcome occurs after stimulus is gone (amnesics can’t learn)

distributed

where is episodic memory located in the brain?

temporal lobe

memory traces stored in

anterograde amnesia

inability to form new memories after injury

retrograde amnesia

loss of memories prior to injury

H.M.

profound anterograde amnesia

some retrograde amnesia

early memories intact

deficits specific to episodic memory (did not form new episodic memories in any modality), but other cognitive abilities intact

phases of episodic memory

encoding → retrieval → consolidation

encoding

process of converting sensory info into a memory trace

retrieval

process of retrieving info from memory storage

consolidation

stabilization of encoded info into long-term memory stores

medial-temporal lobe (MTL)

MTL cortex (PHC/PRC/ERC)

majority of input/output to hippocampus comes from regions of __________ which are highly connected to the rest of the brain

medial-temporal lobe (MTL) and prefrontal cortex (PFC)

involved in successful encoding

hippocampus

supports successful binding of multiple aspects of an experience during encoding

MTL role in memory retrieval

• memories stored as a pattern of activity in brain

• hippocampus/MTL cortex are active when memory is encoded

• hippocampus serves as a “pointer” to perceptual systems in the brain, indexing perceptual features of the memory

• at least some parts of the network that are active during memory encoding are reactivated (reinstated) when memory is retrieved

cortical reinstatement during retrieval

reactivation of cortical neurons active at encoding

pattern separation

hippocampus - keeps memories distinct and prevents interference (confusion) btwn memories

pattern overlap

cortex

Standard Model of Systems Consolidation

episodic memories are transferred from hippocampus to cortex w time

Multiple Trace Theory

new generalized/semantic memories are created in cortex, but hippocampus still needed for “true” episodic memories

evidence: over time, cortex starts to represent commonalities btwn memories