Cranial nerve modulation of human cortical swallowing motor
pathways.
Hamdy, Shaheen, Qasim Aziz, John C. Rothwell, Anthony Hobson,
Josephine Barlow, David G. Thompson.
Department of Gastroenterology, Hope Hospital, University of
Manchester, Salford M6 8HD, and MRC Human Movement and Balance Unit,
Institute of Neurology, Queen Square, London WC1, 3BG, United
Kingdom
APStracts 3:0255G, 1996.
Animal data indicate that cortical swallowing pathways can be
modulated by cranial nerve afferent stimulation. We therefore studied
the effects of human trigeminal and vagal nerve excitation on the
cortico-fugal pathways to the oro-pharynx and oesophagus, using
magneto-electric stimulation. Unilateral stimulation of either the
trigeminal or vagus nerve evoked two distinct reflex
electromyographic responses in the pharynx and oesophagus, an early
response (latency range 19-30 msec) and a late response (latency
range 42-72 msec). In the mylohyoid muscles however, only a single
response was seen (latency range 36-64 msec). Cortical stimulation
also evoked electromyographic responses in the mylohyoid muscles,
pharynx and oesophagus with latencies of 8.5+/-0.3, 9.3+/-0.3, and
10.1+/-0.4 msec respectively. When either trigeminal or vagus nerve
stimulation preceded cortical stimulation, the cortically evoked
responses were facilitated, the effects being maximal at inter
-stimulation intervals of 30-200 msec for the pharynx and oesophagus,
(P<0.02), and at inter-stimulation intervals of 50-100 msec for
the mylohyoid muscles, (P<0.05). Our results demonstrate that
stimulation of human cranial nerve afferents facilitate the cortical
swallowing motor pathways.
Received 22 January 1996; accepted in final form 12 November
1996.
APS Manuscript Number G32-6.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996