Stress shreds thinking but brain gradually stitches it back

January 28th, 2009 - 5:54 pm ICT by IANS  

Washington, Jan 28 (IANS) People under stress have a much harder time juggling attention between various tasks than those who are relaxed but when the tension eases, the mind is able to recuperate quickly, says a new study.Previous experiments had found that stressed rats foraging for food had similar impairments and that those problems resulted from stress-induced changes in their brain anatomy.

The new study by scientists at the Weill Cornell Medical College and the Rockfeller University in New York, using functional magnetic resonance imaging (fMRI) to scan the brains of medical students, is a good example of how basic research in an animal model can lead to high-tech investigations of the human brain.

“It’s a great translational story. The research in the rats led to the imaging work on people, and the results matched up remarkably well,” said Bruce S. McEwen, head of the Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology at Rockfeller University.

The work holds good news for both rats and humans - their brains recuperate quickly. Less than a month after the stress goes away, they are back to normal.

“The message is that healthy brains are remarkably resilient and plastic,” McEwen said.

Researchers scanned the brains of volunteers, some stressed and others relatively relaxed, performing two subtly different kinds of mental tasks, either an attention-shift or a response-reversal.

Lying inside the scanner, the subjects looked at two discs: one red and one green, with one moving up and the other down. In a series of trials, they were prompted to choose a disc according to motion or colour, said a Rockefeller release.

By ordering when the subjects did which tasks, they challenged their volunteers’ brains to either switch focus from colour to motion, or to suddenly reverse their choice of a disc in the same category.

The study was published in the current issue of the Proceedings of the National Academy of Sciences.

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