Figure 8.

Depolarization can block complex spike propagation. A, Evoked CF response in a cell in which just one spike was propagated (axon recording, 220 μm). Strong depolarization with somatic current injection abolished axonal propagation of the CF spike; the ensuing calcium spike was also not propagated. B, Plot of amplitude of the axonal spikelet against the membrane potential averaged over 10 msec before the CF stimulus for the cell shown in A. Note the sharp transition to failed propagation at approximately -45 mV.