Figure 6

Afterhyperpolarization (AHP) improves the time-dependent infidelity of spike propagation on the main axons of cerebellar Purkinje cells. A) Top trace illustrates spikes recorded by a loose-patch on axonal bleb, bottom trace is somatic spikes induced by a whole-cell recording pipette at depolarization pulses (200 Hz) and middle trace shows dV/dt values of somatic spikes under control. The arrows under axon-recorded signals show the failure of spike propagation. Calibration bars are 0.2 mV for axon spikes, 10 mV for whole-cell spikes, 20 mV/ms for dV/dt and 50 ms. B) Top trace illustrates spikes recorded on axonal bleb, bottom trace is somatic spikes induced by depolarization pulses (200 Hz) and middle trace shows dV/dt values of somatic spikes under the condition of giving AHP (biphasic pulses, depolarization plus hyperpolarization in bottom trace). An arrow under axon-recorded signals shows a spike propagation failure on axon. Calibration bars are 0.3 mV for axonal spikes, 20 mV for whole-cell spikes, 60 mV/ms for dV/dt and 50 ms. C) shows spike propagation fidelity vs. somatic spiking time under the conditions of control (black symbols) and biphasic pulses (reds; two asterisks, p < 0.01; n = 9). D) shows maximal dV/dt vs. spiking time under the conditions of control (black symbols) and AHP (reds; asterisks, p < 0.01; n = 9).