Wednesday, January 14, 2004

Was going to post this last week, but I forgot...
Unwanted memories can be driven from awareness, according to a team of researchers who say they have identified a brain circuit that springs into action when people deliberately try to forget something.
I don't know about you, but these days I don't expend much energy 'driving' memories from my awareness -they appear to leave of their own volition.
The findings, published today in the journal Science, strengthen the theory that painful memories can be repressed by burying them in the subconscious, the researchers say.

In the study, people who had memorized a pair of words were later shown one of them and asked to either recall the second word or to consciously avoid thinking about it.

Brain images showed that the hippocampus, an area of the brain that usually lights up when people retrieve memories, was relatively quiet when subjects tried to suppress the words they had learned. But at the same time, another region associated with motor inhibition, called the dorsolateral prefrontal cortex, showed increased activity.

Dr. Larry Squire, a professor of psychiatry and neurosciences at the University of California at San Diego, who did not participate in the study, said it was difficult to say exactly what the brain images meant. Still, concluding that the activity in the prefrontal cortex points to a brain circuit that can block memories, particularly emotional ones, he said, might be too narrow an interpretation.

But Dr. David Spiegel, professor of psychiatry at the Stanford University School of Medicine, said diverting thoughts away from something was the first step to forgetting about it completely. And the study, he added, supported the notion that people could suppress traumatic memories and still regain them later.

"People have to manage vast amounts of information by keeping most of it out of mind, which is true of emotional memories and all others," said Dr. Spiegel, who was not involved with the study. "At any given moment you couldn't remember most of what you know or you'd be overwhelmed. But the memories are there, and you can still recover them down the line."
Ever wonder why these images of our brains are called PET scans? Some neuroscientist's sick joke no doubt. Actually, it stands for 'Positron Emission Tomography'. It's a technique that measures brain activity by the uptake/utilization of a radiolabeled (yes, that nuclear radiation, or nucler if you're unelectable) sugar [energy source]. The good news is that, after November, maybe we'll be able to suppress the memories of the last three years. The bad news is, they won't likely stay suppressed forever. Anyway, neuroscience is the area in which the greatest gains are likely to be made in the next decade ...developing story.


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