Figure 2.

Proposed mechanisms for electrical transmission. (A) The cartoon illustrates the hypothetical current flow generated by an action potential approaching a synaptic terminal (top) and at the synaptic terminal itself (bottom). The initial anodal effect (A1) is followed by a cathodal effect (C2) in the postsynaptic membrane directly facing the presynaptic terminal. (B) Early electrical theory of inhibition. Cartoon illustrates the current flow through the synaptic terminal of an interneuron (G) on a postsynaptic cell (M). To exert an inhibitory action, the interneuron should receive subthreshold stimulation by its afferent input (I). An excitatory input (E) into the postsynaptic cell is also represented. Reproduced from Eccles (1982), with permission.