Figure 6.

Changes in delay during orthodromic propagation. A, Confocal image of the dvn/lvn branch point of the PD axon. The axon was stained with Alexa Fluor 568 hydrazide several millimeters proximal to the branch point. B, Schematic of the recording arrangement for intracellular stimulation from the dvn and extracellular recordings along the motor nerves. Axon branch points are indicated by asterisks. C, The 300th burst of a 5 min stimulation protocol identical to those shown in Figures 4 and 5, evoked by brief depolarizing pulses through the intracellular electrode. The intracellular recording was not balanced for current injection but clearly shows the peaks of evoked spikes. The delays to the spikes in the extracellular recordings show the propagation direction from dvn to pdn. D, Propagation delay between dvn and the three extracellular recording sites for all spikes in the 300th burst. Measurements were taken from the recording traces shown in C. Note that there is a branch point between dvn and lvn and another branch point between lvn and vlvn but none between vlvn and pdn.