A computer model of dorsal cochlear nucleus pyramidal cells: intrinsic membrane properties

Manis [P. B. Manis, J. Neurosci. 10, 2338-2351 (1990)] studied "simple spiking," pyramidal cells of the dorsal cochlear nucleus (DCN) maintained in vitro. Response profiles to hyperpolarizing and depolarizing current pulses were generated. Hyperpolarization of the cell membrane followed by depolarization produced markedly different response profiles from those generated when no prehyperpolarization was imposed. By manipulating the magnitude of the hyperpolarizing and depolarizing pulses, "chopper," "pauser" and "build-up" response patterns, similar to those in vivo, could be generated by individual cells. Manis concluded that the different response profiles resulted from the modulation of intrinsic membrane conductances by the prehyperpolarizing pulses. Here a computer model is used to show that (a) steady-state hyperpolarization can influence cell responding to subsequent depolarization in a manner consistent with the data reported by Manis; and (b) the effects reported can be generated by the addition of a modeled transient potassium conductance to the standard Hodgkin-Huxley model of spike generation [A. L. Hodgkin and A. F. Huxley, J. Physiol. 117, 500-544 (1952)]. The model will be of use to those who wish to consider the role of various excitatory and inhibitory inputs to pyramidal cells and to establish their functional role within the DCN.