Figure 3.
A parent cable bifurcates into two daughter cables (all branches are in the same plane) in the presence of a spatially inhomogeneous extracellular voltage. The external potential Ve that varies over a half-cycle is indicated in color. The cable impedances are matched by applying the 3/2 rule (Rall, 1962). The parent cable is aligned to the external field axis, whereas the angle between the daughter cables and the field axis are as follows: θd,1 = 0° and θd,2 = −45° (A), θd,1 = 45° and θd,2 = −45° (B), and θd,1 = 90° and θd,2 = −45° (C). Below each case, the resulting Vm (second row), Em (third row), and CSDm (fourth row) are shown for ϕs = 0° (blue), 90° (green), and 180° (red). Note that for X > 0.5L, the dashed colored lines illustrate the trajectory of vm along the dashed daughter branch (see first row of the figure) for the three ϕs, whereas the solid colored lines show the trajectory of vm along the solid daughter branch. The daughter branches are of equal normalized length as the parent branch, Lparent = Ldaughter = L/2. The range of Vm, Em, and CSDm along all branches is indicated by the gray areas. Note the increasing attenuation in the induced Em- and CSDm-range as the daughter cable becomes perpendicular to the external field axis.