Figure 2.

Single action potentials backpropagate in remote sites of the basal dendrites. A1, Ca²⁺ transients were detected in two basal branches (top) in response to single action potentials. The probability of detection at the most distal sites is indicated at the levels where the line scans were done (450 and 500 μm from the soma). Note that the average Ca²⁺ transients (n = 30) recorded proximally (250μm) and distally (∼500 μm) in the two basal branches were very similar. A2 illustrates a case in which a failure occurred only in the right proximal branch. B, Mean values of the Ca²⁺ transients observed proximally and distally. In one case, the signal was measured at 950 μm from the soma. C, The amplitude of sodium action potentials did not significantly decrease with the distance from the soma at which the recording electrode was placed in the basal dendrite.