Figure 1

The cord dorsum potential in response to phrenic nerve afferent stimulation in the C5 segment. The trace was the average of 32 stimulus epochs for the middle C5 segment from one animal. The enlarged area expands the large initial peak of the CDP to better illustrate the N1 and N2 peaks. The first negative wave indicates the electrical stimulus used as the zero time point for peak latency analysis. The stimulus artifact is followed by three negative peaks N1, N2, and N3. The amplitudes of the negative peaks were measured from the voltage difference between the peak voltage and the averaged voltage of the 5 ms period before the stimulus onset.