Sf. Woodring et Bj. Yates, RESPONSES OF VENTRAL RESPIRATORY GROUP NEURONS OF THE CAT TO NATURAL VESTIBULAR STIMULATION, American journal of physiology. Regulatory, integrative and comparative physiology, 42(6), 1997, pp. 1946-1956
Stimulation of vestibular otolith afferents by fore-aft tilt (pitch) e
licits changes in activity of nerves innervating respiratory muscles,
including the diaphragm, abdominal muscles, and tongue musculature. To
determine the role of ventral respiratory group (VRG) neurons in prod
ucing these vestibular-respiratory responses, the activity of VRG neur
ons was recorded during natural vestibular stimulation in multiple tra
nsverse planes. Only a small fraction of VRG neurons with inspiratory
(I, 20 of 80 cells), expiratory (E, 11 of 59 cells), or phase spanning
(4 of 16 cells) activity responded to tilts up to 15 degrees in ampli
tude delivered at frequencies fi om 0.02 to 2 Hz. In particular, respo
nses were infrequent in VRG neurons with projections to the spinal cor
d (0 of 23 E cells and 2 of 15 degrees I cells), despite the fact that
the tilts employed produced robust modulation of the activity of abdo
minal (expiratory) nerves. Furthermore, the characteristics of respons
es to tilt of the small fraction of VRG neurons with vestibular inputs
did not match those of respiratory muscles. These data suggest that n
eurons in addition to those in the VRG must participate in generating
vestibular-respiratory responses.