Figure 1. Decrease in the instantaneous firing frequency of a sacral DGC-SPud neurone during distension-evoked micturition.

A, micturition was characterized by a bladder contraction that increased the intravesical pressures sufficiently to expel a stream (indicated with dashed line) of fluid from the urethra. During the micturition reflex, the EUS ENG efferent activity decreased. A decrease in evoked firing of the neurone is evident in the extracellular unit recording, however, because the traces are highly compressed, individual spikes are not discernable and firing changes are better illustrated by the transformed instantaneous firing frequency values. B, averages of the extracellular recording (top) and cord dorsum (lower trace) showing the activation by cutSPud and urSPud (stimulation strength 5T) at latencies of 1.4 and 1.3 ms, respectively. The amplitude calibration in B is for the extracellular spike potential in A and B.