Theoretical response of a bifurcating axon with a locally altered axial resistivity.

A short region of high axial resistivity at one daughter branch of an axonal bifurcation can produce frequency dependent differential conduction of action potentials. The increase in resistivity need be only a few times that in the rest of the axon and length of the affected region need be only a fraction of a resting length constant (based on the local value of axial resistivity). The typical pattern observed will be that the unaffected daughter branch will conduct action potentials from the parent axon normally at all frequencies of stimulation, but the branch with the high resistance region will only follow action potentials within a restricted frequency range. In that band-pass region, the branch may conduct nearly all or only a small percentage of the action potentials from the parent axon.