Saturday, June 9, 2007

How the brain deals with words and digits

inferior frontal gyrus
What happens in the brain when you catch and understand a sentence or if you count a sequence of digits backward? New research with brain scanners has revealed that it depends on the details. That is, on how complex the sentences are. If the brain has to deal with an involved period, it treats it like a sequence of digits that has to be sorted and rearranged. This happens in the brain region coloured red in the picture: The lower front curl of the left side of the brain (inferior frontal gyrus) seems to be a multifunctional region where different kinds of tasks overlap.

This has been shown in a very interesting trial with fifty-eight patients suffering from various forms of dementia and other brain diseases. They had to perform two different tasks while their brains have been scanned by magnetic resonance (MRI). The first task was matching pictures with sentences, either simple or complicated. The second task was counting a given sequence of digits backward, for instance 7-8-9 has to be responded by 9-8-7.

The MRI scanner shows that the brain uses different regions for these two tasks - as long as the sentences are simple. But with more complicated sentences, the brain shifts this task over to a region on the left side of the brain where also the backward counting takes place. Obviously, the brain map is not a fixed landscape but alters its shape, depending on the kind of task. I wonder if we ever will be able to understand our own brain. It may well be impossible at all.

(Picture by Wikipedia)

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