PREFERENTIAL CORRELATIONS OF A MEDULLARY NEURON'S ACTIVITY TO DIFFERENT
SYMPATHETIC OUTFLOWS AS REVEALED BY PARTIAL COHERENCE ANALYSIS.
Cohen, Morton I., Qiping Yu, Wu-Xin Huang.
Department of Physiology and Biophysics, Albert Einstein College of
Medicine, Bronx, NY 10461, USA.
APStracts 2:0133N, 1995.
SUMMARY AND CONCLUSIONS
1. In vagotomized, paralyzed, decerebrate cats, simultaneous recordings were
taken from one or more sympathetic nerves [cervical sympathetic (CS), inferior
cardiac (IC), splanchnic (SP)] and from medullary neurons in vasomo tor-
related regions. Coherence analyses were used to ascertain the presence of
sympathetic rhythms (2-6 Hz or "3-Hz rhythm", 7-13 Hz or "10-Hz
rhythm") that were correlated between different signals. The occurrence of
a significant peak at such a frequency in a unit-nerve coherence spectrum
allowed the iden tification of a medullary neuron as sympathetic-related. 2. A
serendipitous example is given of a rostral ventrolateral medullary (RVLM)
neuron which had significant unit-nerve 10-Hz coherence peaks for 3
sympathetic nerves (CS, IC, SP); but, as revealed by partial coherence analy
sis, the unit activity's correlation with one nerve activity could be partial
ly or completely dependent on its correlation with other nerve activities.
Thus, in this case the unit-CS and unit-IC coherences at 10 Hz were completely
dependent on the SP rhythm, whereas the unit-SP coherence was not significant
ly affected by the CS and IC rhythms. This asymmetry suggests that the neuron
was preferentially connected to SP-generating medullary circuits. 3. This
example indicates the strength of partial coherence analysis as a means of
studying differential connectivity between medullary sympathetic-related
neurons and sympathetic output neuron populations.
Received 25 February 1994; accepted in final form 18 April 1995.
APS Manuscript Number J130-5.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 2 May 1995.