Responses of neurons of the cat central cervical nucleus to natural neck
and vestibular stimulation.
Thomson, D. B., N. Isu and V. J. Wilson.
The Rockefeller University, 1230 York Avenue, New York, NY 10021.
APStracts 3:0144N, 1996.
SUMMARY AND CONCLUSIONS
1. The central cervical nucleus (CCN) is known to receive neck and vestibular
input, and to project to the contralateral cerebellum and vestibular nuclei.
In order to investigate the processing of neck and vestibular input by cells
in the CCN we studied their responses to sinusoidal neck rotation and to
whole-body tilt in vertical planes in decerebrate, paralyzed cats. CCN neurons
were identified by antidromic stimulation with electrodes placed in or near
the contralateral restiform body. 2. For every neuron we first identified the
preferred direction of neck rotation (response vector orientation), then
studied the neuron's dynamics with rotations in a plane close to this
direction at 0.05 to 1 Hz. 3. Responses of CCN neurons to neck rotation
resembled those of previously studied neck spindle primary afferents in terms
of their dynamics and non-linear responses to stimuli of differing amplitudes.
They also resembled the neck responses of Deiters' neurons studied in similar
preparations. 4. The activity of two-thirds of CCN neurons was also modulated
by natural vestibular stimulation. Orientation and dynamics of vestibular
responses were characterized in the same way as neck responses. Labyrinthine
input originated predominantly from the contralateral vertical canals, and
there was no evidence of otolith input. Neck and vestibular inputs were always
antagonistic, but the gain of the vestibular response was lower than that of
the neck response at all frequencies studied. 5. The quantitative aspects of
the interaction between neck and vestibular inputs can be expected to vary
with the type of preparation and with stimulus parameters, and its functional
significance remains to be investigated.
Received 12 March 1996; accepted in final form 25 June 1996.
APS Manuscript Number J199-6.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 25 July 1996