Learning & Memory Flashcards
Sensory memory
Iconic (visual), echoic (auditory), haptic (touch).
Duration: msec-sec.
Capacity: high.
Short term memory/ Working memory (STM to be manipulated)
Duration: sec-min.
Capacity: limited (7 +/- 2).
Long term memory
Duration: days- years (potentially a lifetime).
Capacity: unlimited.
Stages of memory
Encoding
Storage
Retrieval
Multistore model (Atkinson & Shiffrin)
- Sensory memory: sensory input into; unattended info is lost
If attention is paid, transfers to STM. - STM: maintenance rehearsal to remain in STM; unrehearsed info is lost.
Info is encoded into LTM. - LTM: some info may be lost over time (decay); information is then retrieved back into STM to be used.
Short term forms: sensory memory
- Using MEG; occasional deviant auditory stimuli presented within standard stimuli.
- Deviant stimuli generate mismatch field.
Echoic memory: a time course on the order of approx 10s.
Short term forms: STM
- Patient E.E had tumour in left angular gyrus.
- Surgery removing tumour left him with impaired STM but LTM intact.
Evidence for separate regions involved in STM & LTM. Angular gyrus involved in STM.
STM: amnesia
Memory deficits: caused by brain damage, disease or psychological trauma.
Can differentially affect STM and LTM because they have different neural correlates.
Evidence: Clive Wearing (the man with no STM).
- No STM; could not retain new info for more than 30 seconds.
- LTM still intact- remembered his wife and could still play piano (procedural).
Long term forms: declarative memory
= Explicit memory.
Memory for events and facts; conscious access and can be verbally reported.
Episodic memory= personal experience.
Semantic memory= objective knowledge (without context- eg. facts).
Long term forms: non-declarative memory
= Implicit memory.
Types:
- Conditioning- associative learning.
- Priming- prior exposure changes responses.
- Non-associative learning- response decreases/increases with repetition.
- Procedural memory- eg. serial reaction task (response gets faster without participants noticing the sequence).
LTM: amnesia
HM: epileptic had bilaterial medial temporal lobectomy of hippocampus.
- Impaired LTM with intact STM- could not form new declarative LTMs because hippocampus is required for encoding STMs to LTMs.
- Motor senses/procedural memory still in tact- he improved on a motor task without remembering learning it.
This is because declarative memory relies on MTL system (was damaged); and non-declarative memory relies on basal ganglia, cerebellum etc.
Medial temporal lobe system
= Hippocampus, parahippocampal gyrus, entorhinal and perirhinal sulcus.
The hippocampus and these adjacent regions are responsible for establishing long term declarative memories (facts & episodes).
Morris water task: rats
Rats improved day y day at finding a place not directly marked.
However, rats with hippocampus lesion cannot use visual cues suggesting contextual memory relies on the hippocampus.
Delayed nonmatch-to-sample task: monkeys
Monkey has to select a different object after a delay.
Performance impaired after hippocampus lesion.
MTL: human studies
London taxi drivers (cognitive maps): right posterior hippocampus increases in size as a function of years spent as a taxi driver.
- Drivers with hippocampal damage became lost when the roads in a virtual navigation test left the main routes.
Montaldi et al (retrieval activity): retrieval activity was analysed according to familiarity.
- Familiarity (context): parahippocampal cortex.
- Recollection (episodic memory): hippocampus.
