This phenomenon of boosting undetectable signals by resonating with added white noise extends to many other systems – whether electromagnetic, physical or biological – and is an active area of research.
More technically, SR occurs if the signal-to-noise ratio of a nonlinear system or device increases for moderate values of noise intensity.
When the periodic force is chosen small enough in order to not make the system response switch, the presence of a non-negligible noise is required for it to happen.
Stochastic resonance was discovered and proposed for the first time in 1981 to explain the periodic recurrence of ice ages.
Nowadays stochastic resonance is commonly invoked when noise and nonlinearity concur to determine an increase of order in the system response.
[11] Single neurons in vitro including cerebellar Purkinje cells[12] and squid giant axon[13] could also demonstrate the inverse stochastic resonance, when spiking is inhibited by synaptic noise of a particular variance.
SR-based techniques have been used to create a novel class of medical devices for enhancing sensory and motor functions such as vibrating insoles especially for the elderly, or patients with diabetic neuropathy or stroke.