‘Live and learn’: H.M

Ever wondered how scientists came to show that hippocampus in the brain plays an important role in the formation of memories. The best way to show this with 100% confidence is probably do some studies on a person who has his hippocampus removed, right. H.M was one such person who took the field by storm. He’s probably one of the most famous neuroscience patients and has been invaluable to the advancement of the field.

When he was about 27 years old (1953), he underwent an operation to get rid of his frequent seizures. Though the seizures reduced, the operation changed his life completely as he had a memory loss and could not form new memories as well. He couldn’t remember who he spoke to that morning or what he had for lunch that day. During that time it was widely believed that the ability to form memories and retain them was a function that was distributed all over the brain. Through several studies on H.M, Dr. Scoville and Dr. Milner could show that memory can be distinct from other cognitive abilities.

I recently got a chance to attend a seminar by Dr. Suzanne Corkin from MIT who was once a student of Dr. Milner. Corkin (and her lab) studied him for four decades until his death in 2008. I didn’t even know that a person H.M existed until my friend told me about this talk.

Corkin and her students gave several tests to H.M over all the years that they studied him and were able to learn an insurmountable amount about the brain and learning and memory. She told us about how declarative memory could be episodic (event based) or semantic (fact based). Citing her examples – recollecting your dinner time last night would be episodic, you know the capital of France being Paris as a fact but you probably don’t remember when was the first time you ever came to know of it, that’s semantic. Turned out that though H.M had no episodic memory he was still ok with semantic – he could tell things about WWII, which country the US was fighting, so on and so forth. This is just one example and several such interesting things were deduced by experimenting with H.M. After his death, MRI scans of his brain were taken and his brain has been sliced and is now at UCSD.

It was an engaging seminar and at the same time overwhelming that one person who contributed so much to the field (who probably didn’t even know how phenomenal this was for the field) is now no more. Corkin mentioned she is writing a book on H.M and said he was like a family member to her and her lab. She said he was a person with a good sense of humor and he used to say ‘you should live and learn; I’m, living and you’re learning’. When I later asked Corkin about the emotional bonding between them, she said ‘we did as much as we could but that can’t replace what he lost. We celebrated Christmas together and he thought I was his friend from high school’.

Given how closely she worked with H.M and got to know him, I think her book will be a page turner – both scientifically and otherwise. Looking forward to it.