Thursday, 24 April 2008

In Search of Memory

ERIC Kandel is a quite remarkable man. At 78 years old, he says, his career has only just begun. A Nobel prize, award-winning books and countless scientific publications behind him, he has hope for the future of the study of the brain and memory. He can also lay claim to the most magnificent bow tie in science.

On Tuesday, I attended a talk by Kandel entitled "We are what we remember: memory and the biological basis of individuality", held at the Royal Society. Ah, the Royal Society! How great it was to be back there - a building of such history and importance; of such grandeur, too, with it's marble designs, DNA-helix door handles and secret passageways (shh... I didn't mention them!). It was a fine, sunny London evening, and here I was in the most important academy of science in Britain, the Commonwealth and, arguably, the world.

The talk began by addressing the 'systems problem' of memory: where in the brain is memory stored? The first person to seriously consider this was Francis Josef Gall (1768-1828), who declared that all mental functions derive from the brain and that the cerebral cortex is more than just one organ. Therefore, different localities in the brain have different functions. His hypothesis was that the front of the brain is responsible for intellectual functions, the back for instincts and the middle for sentimentality. In addition, Gall believed that bulges of the skull encased enlarged regions of the brain - thus the wisest menfolk had ballooning foreheads and the kindest, most considerate mothers had large, bulbous backs to their skulls (and horrendous, matron-like haircuts to boot).

Gall's weakness was a distrust of (or disinterest in) direct study. Thus when Marie Jean Pierre Flourens (1794-1867) removed the "romantic love" centre from mice brains in 1823, and discovered that this had no effect on the rodent's ability to, er, get amorous, Gall's conclusions were placed in doubt.

Along came Pierre Paul Broca (1824-1880), who believed that brain function was proportional to the phrenology of brain convolutions rather than bumps on the head. His study of Leborgne's brain - an aphasic patient who could understand but not articulate (he could whistle, so his vocal chords were fine); who could use his hands but not write - revealed an area of the brain responsible for the expression of language. This he modestly named the Broca's area.

Meanwhile, Carl Wernicke (1848-1905) found another part of the brain which, when damaged, had the opposite effect: ability to express language but an inability to process and understand it. This, too, was modestly named the Wernicke's area. And so we begin to build up a picture of how the brain functions, in this case with language: we listen and read to take in information that is processed by visual and aural regions of the rear cortex, we then use the Wernicke's area to understand it, and relay this information via the arcuate fasciculus to the Broca's area in order to repeat it, making good use of the nearby motor regions of the brain.

Now, where was I? Ah yes, memory! Kandel did eventually get around to that, but this post is quite long enough already. May I direct you to www.royalsociety.org/live where you should soon be able to listen to the rest of this excellent speech - and marvel at that bow tie.

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