Dendritic control of SS firing. (A1) Bifurcation analysis of the somatofugal equivalent cable with Idc (injected into the active soma). Thick line: Lower bound of the somatic limit cycle corresponding to SS firing (orange: stable, green: unstable). Thin lines: Dendritic voltage at electrotonic distance L = 0.15 from the soma (the spike amplitude is ∼0 at this distance). SS firing arises, as in the isolated soma, from a fold (F) bifurcation and is substituted for by Na-Ca bursting at a torus (T) bifurcation. (A2) F-Idc curves of SS and Na-Ca bursts (see text). (A3) Na-Ca bursting (Idc= 6×103 nAcm−2; black: soma voltage; red: dendritic voltage). (A4) The same as A3, with gc raised to 15 μS. (B) Dendritic control of SS firing by CF (see text). (B1) Idc = −25 nA/cm2. (B2) Idc = 45 nA/cm2. (B3) Idc = 25 nA/cm2. (C) Dendritic control of SS firing by PF EPSCs and SC IPSCs (see text). (C1) Volley of six EPSCs (50 Hz), gPF = 0.5 μS/cm2, Idc = −25 nA/cm2. (C2) Volley of six IPSCs (50 Hz), gSC = 0.5 μS/cm2, Idc = 45 nA/cm2. (C3) Same PF volley as in C1 followed by the same SC volley as in C2 with Idc = 25 nA/cm2.