Neuronal resonance in the theta (4-10 Hz) frequency range is modulated by dynamic changes in the input resistance

Most neurons of the mammalian brain display intrinsic resonance with frequency selectivity (fR) for inputs within the theta-range (4-10 Hz). Variations in network oscillation along this range depend on the animal behavior; however, whether neurons can dynamically tune their fR has not been addressed. Using slice electrophysiology, dynamic clamping and computer modeling we studied three types of cortical neurons, finding that the input resistance (Rin) inversely sets fR into the theta range, following a power law. We demonstrate that physiological changes in Rin modulate fR and response phase, serving as a mechanism that instantaneously tunes oscillatory responses. Moreover, these modulations are translated into spiking regimes, modifying spike frequency and timing. Since synaptic inputs reduce Rin, this modulation provides a mean for adjusting the frequency and timing of firing of individual neurons in interplay with the network fluctuations. This might be a widespread property among resonant neurons.