The Unforgettable Amnesiac 120
jamie found an account in the NYTimes of the life and death of one of the most important figures in modern neuroscience, Henry Gustav Molaison — a man who could not form memories. Molaison became an amnesiac after a brain operation in 1953. Known worldwide as H.M., Molaison was studied intensively for 55 years. Dr. Brenda Milner, a psychologist from Montreal, was the first researcher to visit Molaison. In 1962 she authored a landmark study demonstrating that a part of Molaison's memory was fully intact. "The implications were enormous. Scientists saw that there were at least two systems in the brain for creating new memories. One, known as declarative memory, records names, faces and new experiences and stores them until they are consciously retrieved. ... Another system, commonly known as motor learning, is subconscious and depends on other brain systems. This explains why people can jump on a bike after years away from one and take the thing for a ride, or why they can pick up a guitar that they have not played in years and still remember how to strum it. Soon 'everyone wanted an amnesic to study,' Dr. Milner said..."
I believe this was part of the inspiration (Score:5, Informative)
Re:Interesting case (Score:5, Informative)
Re:Offered his brain for further scientific study (Score:3, Informative)
Re:Authored???? (Score:5, Informative)
Author has been a verb (and a noun) since at least 1596 (oed) [oed.com].
H.M. Is the Father of my Field (Score:5, Informative)
The most important contribution of H.M. is helping pin down the fact that for Episodic memory, the Medial Temporal Lobe is critical. From there a whole lot of work has been done pinning down the sub regions of the Medial Temporal Lobe with memory function:
The hippocampus: CA1 CA3 and dentate gyrus, is important for associating memory traces with contexts. The surrounding cortices important for making global assessments of the familiarity of a memory trace. Look up Professor Andrew Yonelinas at his UC Davis website for some current reviews of Recollection and Familiarity processes.
Re:Offered his brain for further scientific study (Score:3, Informative)
Re:What was I going to post? (Score:5, Informative)
New Topic:
H.M. learned how to solve the Tower of Hanoi (documented by decreasing time to solve) but denied ever seeing the Tower of Hanoi before.
This is an example of some evidence that distinguished between semantic(facts) and episodic(event) memory systems.
Link to another interesting article (Score:5, Informative)
I find this stuff fascinating. Oliver Sacks [wikipedia.org], who has researched this condition, wrote a lengthy article about Clive Wearing [newyorker.com], who is another person with the same condition as H.M.
Re:Authored???? (Score:5, Informative)
Re:H.M. Is the Father of my Field (Score:3, Informative)
mea culpa - Yes, I did mean finite state machine. Though a complex cascade of flying spaghetti monsters has a certain ring to it.
Re:Offered his brain for further scientific study (Score:5, Informative)
One of the quotes from H.M. I always read in my neuroscience classes:
"Right now I'm wondering, have I done or said anything amiss? You see, at this moment everything looks clear to me, but what happened just before? That's what worries me. It's like waking from a dream; I just don't remember.... Every day is alone in itself, whatever enjoyment I've had, whatever sorrow."
RIP, Henry.
It doesn't matter. (Score:2, Informative)
3 Case Studies (Score:3, Informative)
Due to an accidental needle stick while working in surgery, I contracted hepatitis C. I didn't know it until my liver almost stopped working. The way I found out about it was being told that I'd totaled my van the day before as well as having two other accidents. In all 3 cases the police came and didn't detect any evidence of intoxication. And I wasn't intoxicated. But I was anesthetized. I was taking prescribed amounts of Ativan and Benadryl. My liver wasn't clearing them out of me, and they built up to a level that made me a fully functional zombie. I've since had another episode of amnesia caused by medication, and my liver is running at 100% now. I took Ambien, and ended up 2 days later finding out that I'd spent the previous 2 days eating all 30 days worth of the stuff, forgetting that I'd taken any previously. The first dose caused it. And it's even listed as a side effect: "can cause sleep walking with no memory of the event". It's not sleepwalking, but it's a good description anyway.
The most distressing case of amnesia I ever saw was an educational movie about a man who had been an orchestra conductor, had been in an accident, and due to the whiplash effect of the brain inside the skull, sustained brain damage in the hippocampus, where memories are formed. The best (or worst, you decide) example of what a person goes through was shown in the movie as he wrote in his journal "I have just woken up. I have only just this moment become aware." Over, and over, and over, day after day.
I once visited a man in a nursing home who had amnesia. He was due to all the thiamine (vitamin B-1) being washed out of his hippocampus by alcohol. Commonly called "wet brain", its clinical name is Wernicke-Korsakoff syndrome. It appears almost exactly like Alzheimer's. You can tell the difference by giving the person a list of words to remember. Later, ask them to recall the words, and neither can. But give the first two letters of the words, and the W-K patients can recall the words. They have implicit memory -- they can remember, but they don't know they remember. The Alzheimer's patients can't recall even having been given the list if shown the complete list later. As I spoke with this man, he frequently interrupted and asked me my name, what I do for a living, and similar questions, and asked these same questions again every couple minutes. He never once caught on to the fact that I was his son, and I didn't bother to tell him, because he wouldn't have remembered it just a few minutes later.