“…Two interesting observations were made in this cell type: (i) the axon mainly arises from a dendrite (axon-bearing dendrite or ABD), at distances from the soma reaching 200 µm (Figure 2A; Hausser et al, 1995;Gentet and Williams, 2007;Meza et al, 2018;Moubarak et al, 2019); and (ii) the AP recorded in different compartments of the neuron (ABD, soma or non-ABD) shows virtually no attenuation in its amplitude ( Figure 2B) although it is always initiated at the AIS (Hausser et al, 1995;Gentet and Williams, 2007;Moubarak et al, 2019). This faithful back-propagation, which appears highly reliable during spontaneous pacemaking (Gentet and Williams, 2007;Blythe et al, 2009;Moubarak et al, 2019) may be abolished under specific conditions, for instance when barrages of EPSPs onto the ABD are used to trigger firing or when dopamine is used to dampen somatic excitability (Gentet and Williams, 2007). Since the seminal observation of Hausser et al (1995), faithful back-propagation has been described in at least two other mammalian cell types, the olfactory bulb mitral cells (Figure 2A; Bischofberger and Jonas, 1997;Chen et al, 1997;Xiong and Chen, 2002) and the oriens-alveus interneurons of the hippocampus ( Figure 2B; Martina et al, 2000).…”