Key Experiments + People

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Karl Lashley 1927 - Failed to locate a physical representation of memory in the brain (an engram)

Scoville 1953 - Bilateral removal of HM's MTL

Dr A Alzheimer 1906 - Characterised Alzheimers

Godden & Baddley's Diving Experiment

Used as evidence for State Dependency Theory

underwater/land, noise/quiet, happy/sad

shows people encode context alongside the memory

Goodwin et al.

Used as evidence for State Dependency Theory

48 male medical students over 2 days

4 groups: 1) Sober/Sober, 2) Sober/Drunk, 3) Drunk/Sober, 4) Drunk

Word recall was state dependent but picture recognition wasn't

Thompson & Neely 1970

When ECS was administered only before the trial or before the test, retention was impaired

When ECS was administered at the same time before the trial and the test, retention was normal

Maybe the 2nd ECS reversed the 1st and the memory isn't erased, which is at odds with consolidation theory

Maybe there's a post-ECS 'brain state' encoded with the memory about the trial

2nd Experiment

3 Mazes

A - shock avoidance

B - gaining a reward

C - shock avoidance

administer ECS before A, B and C

Consolidation Theory predicts, Memory A will be strongest, with B next and C the weakest

But A & C were forgotten and B retained

So maybe ECS affected material that was related to existing material, leaving intact islands of memories spared (B)

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Squire et al. 1976

ECT produced a temporal gradient of retrograde amnesia

so older memories were more intact than newer ones

the length of time interval didn't affect retention like ECS

Dudai 2004

Reconsolidation Theory, each time a memory is retrieved it can be distorted and then put back into long term memory

useful for traumatic memories which can be selectively lost/dampened

Real, w/loads of applications

Sleep and consolidation

Correlation between the extent of regional hippocampal cerebral blood flow during slow-wave sleep and the extent of post-sleep improvement in a spatial recognition task

Scans during slow-wave sleep, showed experience dependent reactivation of neural circuitry involved in learning