Stochastic resonance, a nonlinear phenomenon in which random noise opt
imizes a system's response to a signal, has been postulated to provide
a role for noise in information processing in the brain. In these exp
eriments, a time varying electric held was used to deliver both signal
and noise directly to a network of neurons from mammalian brain. As t
he magnitude of the stochastic component of the field was increased, r
esonance was observed in the response of the neuronal network to a wea
k periodic signal. This is the first demonstration of stochastic reson
ance in neuronal networks from the brain.