Thursday, November 14, 2013

Memory: The Relationship Between Brain and the Experience of 'Self'

Interesting article in Time Magazine about a woman named Lonni Sue Johnson who was a very successful artist, violinist and pilot until she suffered an attack of encephalitis in 2007 at the age of 57.  Studying patients like Johnson, scientists are learning about the relationship between the physical brain and experiences and even the nature of 'self'.
With the help of the hardware and Johnson's willingness to sit still for so much study, science may be able to answer one other, more abstract question: What is it like to have lost so many memories about your life and the world? If who you are is an amalgamation, at least in part, of the things you've experienced--the people you've loved, the places you've lived, the tragedies you've endured--are you actually you at all when those things are wiped away? The self is ineffable, but it's also material, the product of neurochemicals sparking their way through living tissue. How we draw the line between those two dimensions--the biological and the experiential, the brain and the far less knowable mind--has kept philosophers awake for millennia.

But how do we know?
Johnson, with her profound damage to the material self, may help us better understand the immaterial one.
And here is where it starts to get REALLY interesting.
Brain scans revealed that her encephalitis had effectively destroyed her hippocampi, a pair of sea-horse-shaped structures deep in the brain's basement. It also did extensive damage to structures surrounding the hippocampus, including areas known as the perirhinal cortex and the parahippocampal cortex. That was very bad news since the job of the hippocampus is to consolidate short-term memories into permanent, long-term ones. If the hippocampus isn't there to do that work, everything starts over every few minutes. 
The reason, explains Larry Squire, a professor of psychiatry at the University of California at San Diego, is that what seems like a single memory is actually many memories in different parts of the brain. The recollections you have of last year's Thanksgiving dinner, for example, consist of sights and sounds and smells and tastes and deeper links to the people who were there, all of which are processed in different parts of the brain. It's the job of the hippocampus to act like the attentive host at a party making introductions among all those parts. "It's a common mistake to think that memories are initially in the hippocampus and then get shipped somewhere," says Squire. "They're never shipped. They're always somewhere else."

I don't need to copy the entire article here but this little bit blows me away.
The slow recovery Johnson has made offers other clues about how memory works. Months after she started painstakingly copying lines, Johnson began sketching without help. Eventually, says Aline, "the little people came back." Tiny human figures had been a hallmark of Johnson's pre-amnesia art. "It was one of the first indications that those images were still inside her head. If it weren't for the art, how would we know they were there?" But exactly where they'd been hiding or how they were flushed out remain unclear. 
Equally mysterious is why Johnson can identify her pre-encephalitis drawings as her own, despite the fact that she can't identify even the world's most famous paintings except the Mona Lisa. "Whatever it is that allows her to recognize her own style is incredibly complex," says Johns Hopkins cognitive neuroscientist Barbara Landau, who works with Johnson. "I don't think we know how to characterize it."
This is classic science.  In practice, answers to one question only reveals the next set of questions, perhaps even more mysterious than the first.

And so it goes. 

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