The frequency sensitivity of weak periodic signal detection has been studie
d via numerical simulations for both a single neuron and a neuronal network
. The dependence of the critical amplitude of the signal upon its frequency
and a resonance between the intrinsic oscillations of a neuron and the sig
nal could account for the frequency sensitivity. In the presence of both a
subthreshold periodic signal and noise, the signal-to-noise ratio (SNR) of
the output of either a single neuron or a neuronal network present the typi
cal characteristics of stochastic resonance. In particular, there exists a
frequency-sensitive range of 30-100 Hz, and for signals with frequencies wi
thin this range the SNRs have large values. This implies that the system un
der consideration (a single neuron or a neuronal network) is more sensitive
to the detection of periodic signals, and the frequency sensitivity may be
of a functional significant to signal processing.