Putative projection of phrenic afferents to the limbic cortex in
man studied with cerebral evoked potentials.
Straus, Christian, Marc Zelter, Jean-Philippe Derenne, Bernard Pidoux,
Jean-Claude Willer, Thomas Similowski.
Laboratoire de Physiopathologie Respiratoire du Service de
Pneumologie, Service Central d'Explorations Fonctionnelles
Respiratoires, Service d'Explorations Fonctionnelles du
Syst[grave]eme Nerveux, Groupe Hospitalier Piti[acute]e
-Salp[circumflex]etri[grave]ere, Paris, France
APStracts 3:0483A, 1996.
Respiratory sensations may rely in part on cortical integration of
respiratory afferent information. In an attempt to study such
projections, we recorded evoked potentials (EP) at scalp and cervical
sites in ten normal volunteers undergoing transcutaneous phrenic
stimulation (PS)(0.1 ms square pulses, intensity liminal for
diaphragmatic activation, series of 600 shocks at 2 Hz). A negative
cerebral component of peak latency 12.79+/-0.54 ms (N13) was
constant, and a negative spinal component (7.09+/-1.04 ms, N7) could
also be recorded, all results being reproducible over time.
Monitoring of cardiac frequency, skin anaesthesia, and stimulation
adjacent to the phrenic nerve made the phrenic origin of N7 and N13
the foremost hypothesis. Increasing stimulation frequency, and
comparison with median nerve stimulation provided arguments for the
neural nature of the signals and their cerebral origin. Recordings
from intracerebral electrodes in a patient showed a polarity reversal
of the EP at the level of the cingulate gyrus. In conclusion, PS
could allow one to study projections of phrenic afferents to the
central nervous system in man. Their exact site and physiologic
meaning remain to be clarified.
Received 6 September 1995; accepted in final form 15 October
1996.
APS Manuscript Number A976-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 13 November 1996