The random fluctuations of noise generally add unwanted messiness to a signal. But sometimes noise can actually pump up small signals and make them detectable. When background noise and a faint signal have similar frequency components, the two add constructively and can crank up the signal's strength. Scientists first noticed these "stochastic resonances" 20 years ago as peaks in the annual global climate temperatures brought out by the "noise" of variations in solar radiation. Since then, signals buoyed by noise have been spotted in biological, electrical, and chemical systems. The team discovered that a controlled amount of noise gave the signal enough energy to push itself across from one diode to the next, despite the barriers. Too little noise, and the signal doesn't make it. Too much noise distorts and corrupts the signal.
We are currently investigating how noise might play a key role in communication among neurons in the brain, by helping to push signals from cell to cell.