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HM case study of amnesia ...

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HM -

Epilepsy not treated by drugs Surgery late 20s Removed focus of where it stemmed from – hippocampus (centre of medial tempol lobe) It helps cure, but HM couldn’t form new memories Didn’t lose them from lifetime – doctor came in everyday and he didn’t recognise him If probed – he could not remember yesterday to explain it Most theories of localisation of the brain – memories are distributed all over. One part of the brain used for one kind of memory

Sue Corkin - Interrogated HM - Assumed this part of the brain was specialised for declarative memory – what happened the day, day before. Everything else was intact. However, this turned out not now be true – other more subtle changes in his behaviour - Other people with damage to the hippocampus now - suffer from memory loss (a lot) - Example If you ask people to imagine a scenario – with a hippocampus people don’t imagine it in the same way. Hippocampus damage – don’t have detail to it at all Brenda Milner – neuropsychology 1950 – would study and test pateints before and after surgery before and after. Pat of hippocampus removed Testing – if found patient had memory deficit already, had to be much more careful when operating 1952 – accumulated enough evidence of mild deficits on some deficit tasks (more on right) Patients would come with left sided lesions – ‘such trouble with memory’. Because patients said they had trouble with memory, that is what she tried to focus on. 2 patients – severe memory impairment for epilepsy Milner perused testing of Penfield patients – presented findings on post-surgical findings Studied HM over several years – he never remembered her from one visitation to the next One test – mirror drawing test (brain had more than one memory system) HM over three days of testing got better and better at drawing – no recollection of the three days training beforehand, he was proud he could do it well Evidence there’s more than one learning system in the brain Took a single patient and by asking the right questions tease out the fundamentals of memory. IN 60s looked at frontal lobes. Card sorting task to reveal a deficit with front love lesions. Frontal patients – repetitively doing something incorrect been though they were being told repetitively they were doing wrong Left and right hemispheres of the brain

Right – ‘spare type’, but she didn’t believe this

Suzanne Corkin -HM Horizontal section of his brain shows imaging. Bright white fluid is cerebral fluid. Is cerebellum is attributed (shrunk) after taking anti-seizure medication. Lesion in temporal lobes. 5.4cm of damage, 5.1cm on right side. Overestimated tissue was taken out. It was nearer 8cm. The night he died – scanned him over 9 hours His ventricles are large, corpus collosum is thin Autopsy on brain – back shrivelled cerebellum should come out further on each side. Tips of temporal lobes – lesion begins after tip of lobe progresses back (surgeon deliberately stopped so he didn’t cause more damage)...