Figure 1. Model of an active dendritic tree with non-stereotyped dendritic spikes.

(a), Excitable elements (circles) connected (bars) in a Cayley tree topology with G = 3 layers and coordination number z = 3 (one mother and k = 2 daughter branches). Large green (yellow) arrow illustrates forward (backward) propagation. (b)–(d), Biologically motivated dendritic spike with duration depending on the distance from the soma as a net effect of variable density of ionic channels. Red arrows indicate that the site is being stimulated (by an external input and/or by mother or daughter branches), and represents the average period of dendritic spikes at layer g.