Subthreshold response to white-noise current input in a tapering cable model of a neuron

^* Author to whom all correspondence should be addressed The expectation (mean) and variance of the depolarization inthe absence of a threshold for action-potential generation isobtained in a neuron model represented by a tapering equivalentcable with a random (white noise) synaptic input current ata point along the dendrites. The results show that the introductionof a taper in the equivalent-cable representation of the neuronproduces larger values for both the expectation and variancewhich are neither insensitive nor symmetrical with respect tothe location of the input. It is also shown that taper extendsthe invariance of the variability in the steady-state somaticresponse to proximally located random inputs, implying thatonly small changes in the noisiness of the somatic responseoccur for a random input located in the dendrites.