White noise analysis of cable properties of neuroblastoma cells and lamprey central neurons.

The integrative properties of two kinds of excitable cells, a cultured neuroblastoma cell and the lamprey giant interneuron, are described using a white-noise impedance method. The impedance functions were fitted with a neuron model consisting of an isopotential soma plus a single equivalent dendritic process, which contained up to 16 equal elements. The frequency-domain characteristics of both the passive and active conductances were used to estimate the dendritic-to-soma areas, the electrotonic length of an equivalent dendrite, the membrane time constant, and the relaxation time constants associated with the voltage-dependent conductances. The effect of differing degrees of synaptic input was simulated by localizing the synaptically activated conductances to the soma, a point at the end of the dendrite, or the entire dendritic membrane.