The modern neuroscience of memory
Unlike the post below, there is a very small but salient Irish connection to this post. Henry Molaison (known as H.M.) was the most important neuropsychological patient of all time. He died in 2008, having spent his life suffering from a profound, enduring and non-resolving anterograde amnesia, which happened as the result of a ‘frankly experimental’ operation on his brain to relieve his epilepsy. The surgery removed the hippocampus in both sides of his brain. His epilepsy developed after a road traffic accident, and it was refractory to drug treatment. In modern experimental psychology parlance, his working memory/short-term memory was intact, and his memory for remote events was reasonably intact, but his ability to convert short-term memories into long-term memories was lost permanently (‘anterograde’ amnesia).
H.M. was studied continuously for about 55 years or so. Neuroscience learned much from him about the nature of memory, how it becomes instantiated in the brain, the difference between brain systems responsible for what now referred to as explicit (or declarative) and implicit (procedural) memories. Nobel prizes, a massive research industry, the quest to understand and treat Alzheimer’s Disease and other diseases of the ageing brain that impair memory function, even important elements of modern brain surgery, are all founded around the framework for understanding the neurobiology of memory deriving from the study of H.M.
The New York Times has run an interesting story on the post-mortem treatment of H.M.’s brain. It is being carefully sectioned, and will be digitised for further study. Money quote:
An entire brain produces some 2,500 slices, and the amount of information in each one, once microscopic detail is added, will fill about a terabyte of computer storage. Computers at U.C.S.D. are now fitting all those pieces together for Mr. Molaison’s brain, to create what Dr. Annese calls a “Google Earthlike search engine,” the first entirely reconstructed, whole-brain atlas available to anyone who wants to log on.
The story is at: http://www.nytimes.com/2009/12/22/health/22brain.html, and there are some remarkable images published in the story. H.M.’s obituary is at http://www.nytimes.com/2008/12/05/us/05hm.html.
And the Irish connection? H.M.’s unnamed mother was from Ireland (I did say a small but salient connection).