Dmitri Chklovskii, Armen Stepanyants
What determines the caliber of axonal branches? We pursue the hypothesis that the axonal caliber has evolved to minimize signal propagation delays, while keeping arbor volume to a minimum. We show that for a general cost function the optimal diameters of mother (do) and daughter (d], d2 ) branches at a bifurcation obey h a ranc mg aw: e envatIOn re les on t e fact that the conduction speed scales with the axon diameter to the power V (v = 1 for myelinated axons and V = 0.5 myelinated axons). We test the branching law on the available experimental data and find a reasonable agreement.
d v+2 d v+2 d v+2 Th d " 0 = ] + 2