Random noise may improve the human brain's ability to process information, according to recent research by two physicists in Japan. Toshio Mori and Shoichi Kai of Kyushu University have shown that the visual-processing region of the human cortex responds better to an external periodic stimulus when external noise is also applied. The findings represent yet another example of the seemingly ubiquitous phenomenon of stochastic resonance - and is one of the most interesting biological examples to date (2002 Phys. Rev. Lett. 88 218101).
The notion of stochastic resonance was originally introduced in relation to the Earth's ice-age cycle, in an attempt to explain how a tiny periodic variation in the amount of radiation reaching the surface of the planet could trigger the huge climatic changes that have been discovered. In stochastic resonance, a weak periodic signal in a noisy system can be enhanced by adding extra noise. Even more remarkably, there are many cases where the signal-to-noise ratio, as well as the signal, is enhanced by the addition of noise.
In the July issue of Physics World, Peter McClintock of Lancaster University, UK, explains how the Kyushu team detected the phenomenon in the brains of five students.