The BPRs mechanism was analyzed by tracking transmembrane currents and intracellular axial currents in different cellular compartments using the Z+ PC type I model, in which the intrinsic ability to generate BPRs was evident (Figure 3A). In the PC model, APs arise from the AIS (Masoli et al., 2015) and, not surprisingly, the pause is characterized by a protracted decrease of the AIS transmembrane current (IAIS; Jack et al., 1975). In fact, this makes the pause appearing as an interruption of pacemaking. Pacemaking in PCs is sustained by the persistent Na currents generated mostly in AIS and by Ca currents generated mostly in the dendrites and transmitted to the AIS through the internal resistance (Llinás and Sugimori, 1980a,b), providing two candidate mechanisms for pause generation.