23 October 2009

How the brain creates "time"

Perhaps the most fundamental question neuroscientists are investigating is whether our perception of the world is continuous or a series of discrete snapshots like frames on a film strip. Understand this, and maybe we can explain how the healthy brain works out the chronological order of the myriad events bombarding our senses, and how this can become warped to alter our perception of time.

It seems that each separate neural process that governs our perception might be recorded in its own stream of discrete frames. But how might all these streams fit together to give us a consistent picture of the world? Ernst Pöppel, a neuroscientist at the Ludwig Maximilian University in Munich, Germany, suggests all of the separate snapshots from the senses may feed into blocks of information in a higher processing stream. He calls these the "building blocks of consciousness" and reckons they underlie our perception of time

"Perception cannot be continuous because of [the limits of] neural processing," says Pöppel. "A space of 30 to 50 milliseconds is necessary to bring together in one time-window the distributed activity in the neural system."

-- from New Scientist magazine (http://tinyurl.com/yh8ebs9)

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