Archive for August, 2009

ConsciousnessMatrix3By Jim Schnabel

Does consciousness—our awareness that we are perceiving something—arise from a special region in the brain, or from the coherent workings of multiple regions? Analyzing data from electrodes implanted in the brains of epilepsy patients, French researchers suggest the latter, although their results, published March 17 in the online journal PloS Biology, also point to a role for special, consciousness-related circuits in the prefrontal cortex.

Lionel Naccache, senior author on the paper and a researcher at Pitié-Salpêtrière, a teaching hospital in Paris, says he found that ordinary nonconscious visual perception was reflected in a quick sweep of activity from the primary visual cortex at the back of the brain to the prefrontal cortex. Such activity was liable to fade away just as quickly, but above a certain threshold, it evoked a sustained “long-distance coherent communication” between prefrontal areas and other areas of the cortex, a phenomenon that corresponded to conscious perception in his research participants.

“It’s a nice paper,” says Christof Koch, a neuroscientist and consciousness researcher at the California Institute of Technology. “If one can generalize this result [in other humans] and maybe do it in monkeys, it could be useful as a signature of consciousness. So it’s definitely a step forward.” Read more…

Source: The Dana Foundation

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