COMPARISON OF RESULTS OBTAINED WITH TIME-DOMAIN AND FREQUENCY-DOMAIN ANALYSIS WHEN SEARCHING FOR THE 10-HZ RHYTHM IN SYMPATHETIC-NERVE DISCHARGE

Kubota et al. (Neurosci. Lett., 196 (1995) 173-176) constructed distri butions of the intervals between successive bursts of sympathetic nerv e discharge (SND) in three mammalian species, The mode in such interbu rst interval histograms (IBIHs) was near 100 ms in most cases. This in terval was equated with the 10-Hz rhythm in SND identified by others u sing power density autospectral analysis. However, in the current stud y we found a modal interval near 100 ms independent of whether the aut ospectrum showed a peak near 10 Hz. A 10-Hz rhythm appeared in the aut ospectrum of SND only when counts in the IBIH were normally distribute d around 100 ms and the coefficient of variation was <0.25. We conclud e that a modal interval of 100 ms, by itself, is not a predictor of a 10-Hz rhythm in SND. As such, the conclusions of Kubota et al. on the spinal origin and ubiquity of the 10-Hz rhythm are open to question.