We report a facilitatory role of inhibitory synaptic input that can enhance a neuron’s firing rate, in contrast to the conventional belief that inhibition suppresses firing. We study this phenomenon using the Hodgkin-Huxley model of spike generation with random Poisson trains of subthreshold excitatory and inhibitory inputs. Enhancement occurs when, by chance, brief inhibition leads excitation with a favorable timing and counterintuitively induces a reduction of the spike threshold. The basic mechanism is also illustrated with the phaseplane analysis of a two variable model.

• Received 18 August 2005

DOI:https://doi.org/10.1103/PhysRevE.73.010903