While sector I phenomena remained almost locally confined, the voltage-dependent effects initiated in sector II rapidly spread to neighboring sectors and eventually to the whole dendrite (Figure 8B). Full-blown calcium spikes appeared with some delay in a region close to sector II, involving LVA followed by HVA calcium channel activation causing a large [Ca2+]i raise and eventually KCa activation and the pause. Therefore, also dendritic sectors that are not activated synaptically can generate a local [Ca2+]i increase and take part to control the BPR pause.