What turns the firings of the millions of neurons in our brains into coherent thought? Persuasive connections are made in two research reports in Nature, in which concious actions are linked with the synchronous firing of networks of neurons. Even more interestingly, these phases of synchrony are actively unravelled soon after - like marching soldiers actively breaking step while walking across a bridge - to allow other networks of neurons to fire synchronously, as the basis for the next thought or action.
Experimenters working with EEGs (electroencephalographs, which measure electrical activity in the brain) have long known about ?gamma waves?, in which neurons fire at a rate of between 40 and 70 Hz (cycles per second). Transient periods in which entire banks of neurons from different parts of the brain start firing in synchrony over the gamma waveband have been proposed as a mechanism for bringing a widely distributed set of neurons together into a coherent ensemble that underlies a cognirtive act, such as perception. This idea has received support from work on animals, but has hitherto not been established in humans.
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