Figure 2

The velocity and fidelity of spike propagation on the main axons of cerebellar Purkinje cells (PC) decrease when spiking time increases. A) Top trace shows spikes recorded by loose-patch on axonal bleb, bottom trace is somatic spikes induced by a whole-cell recording pipette at depolarization pulses 100 Hz, and middle trace shows dV/dt values of somatic spikes. Calibration bars are 0.1 mV for axonal spikes, 20 mV for whole-cell spikes, 60 mV/ms for dV/dt and 50 ms. B) shows the spikes on axons (top traces) and the dV/dt of somatic spikes (bottom traces) in initial (red), middle (green) and late phases (blue) under the conditions of spike frequencies at 100 Hz (left column) and 200 Hz (right). The traces in different colors are taken from the boxes in 2A and 1B with corresponding colors. C) shows the normalized velocity of spike propagation vs. time at 100 Hz of spikes. D) illustrates the normalized velocity of spike propagation versus time at 200 Hz of spikes. The velocity of spike propagation decreases to two levels, level one (blue dash line) and level two (purple). Red vertical bars show time points of spike propagation failure. E) shows normalized spike propagation velocity vs. time under the conditions of spike frequencies at 100 Hz (black symbols) and 200 Hz (reds; n = 12). F) illustrates spike propagation fidelity (a ratio of axonal spikes to somatic ones) vs. time under the conditions of spike frequencies at 100 Hz (black symbols) and 200 Hz (reds; n = 12).