The biophysical properties of spines as a basis for their electrical function: a comment on Kawato and Tsukahara (1983).

In a theoretical study of the passive cable properties of dendritic spines Kawato & Tsukahara (1983) claim to have proved that “the dendritic spine has no significant electrical function” (from their discussion). However, Kawato & Tsukahara restrict their analysis to current inputs to spines. Since the dimensions of spines are very small, their input resistance is expected to be very large and the synaptic input to spines has to be modeled as conductance change. Under this assumption, spines show interesting (non-linear) electrical properties: i) the somatic potential induced by an excitatory synapse on a spine may depend strongly on the shape of the spine and ii) the effect of inhibition might be confined to the spine