The currents in the main dendrite were a mixture of somatic and dendritic currents, and like the membrane potential they combined the characteristics of both parts of the cell in their dynamic changes (Fig. 11B). Two aspects are noteworthy. The CaP channel in the main dendrite was activated during the somatic action potential and thus contributed to the broadened base of these Na+ spikes. Correspondingly, there were small activations of the Ca2+ -activated K+ currents during each somatic spike. However, the delayed rectifier was a more important current in the main dendrite during the depolarizing spike burst than the K2 current.