DIFFERENTIAL RELATIONSHIPS AMONG THE 10-HZ RHYTHMIC DISCHARGES OF SYMPATHETIC-NERVES WITH DIFFERENT TARGETS

Partial coherence analysis was used to remove the influences of the ce ntral circuits controlling a sympathetic nerve (as reflected by its di scharges) on the coherence of the 10-Hz discharges of other sympatheti c nerves in unanesthetized decerebrate or urethan-anesthetized cats. I n many cases, partialization reduced but did not eliminate the sharp p eak near 10 Hz in the coherence functions relating the discharges of s ympathetic nerve pairs. This observation implies that the central sour ces of the 10-Hz rhythmic discharges of any nerve are not identical to those responsible for the rhythm recorded from any other nerve. Parti al coherence analysis also revealed differential relationships among t he 10-Hz rhythmic discharges of sympathetic nerves with different targ ets. Importantly, the pattern of differential relationships observed i n one experiment could be the reverse of that in the next. Although th e basis for the differential relationships is not yet clear, nonunifor m coupling of multiple brain stem 10-Hz oscillators and/or nonuniform cross talk between spinal circuits controlling different sympathetic n erves may be involved.