Two-compartment stochastic model of a neuron

A two-compartment neuronal model is investigated. The model neuron is composed of two interconnected parts – a dendrite and a trigger zone, with a white noise input in the dendritic compartment. The first and the second moments of the stochastic processes describing the membrane depolarization in both compartments are derived and investigated. When a firing threshold is not imposed, the level of neuronal activity is deduced from a generally accepted relationship between the membrane potential and the firing frequency. When a firing threshold is imposed, some approximations and simulations are used to characterize the spiking activity of the model. It is shown that the activity of the two-compartment model is less sensitive to abrupt changes in stimulation than the activity of the single-compartment model. The delayed response of the complex model is a natural consequence of the fact that the input takes place in the compartment different from that at which the output is generated. Further, the model predicts serial correlation of interspike intervals, which is a phenomenon often observed in experimental data but not reproducible in the single-compartment models under steady-state stimulation. Finally, the investigated model neuron shows lower sensitivity to the input intensity and larger coding range than the single-compartment model. ©1999 Elsevier Science B.V. All rights reserved. PACS: 87.10.+e; 05.40.+j