Recordings were made from nerves innervating ventral lumbar paraverteb
ral muscles (quadratus lumborum) during natural vestibular stimulation
in vertical planes. The best direction of vestibular stimulation for
producing an increase in nerve activity was near nose-up pitch in two-
thirds of the animals, but was near nose-down pitch in the others. The
response gain (re. position) was fiat across the frequency range of 0
.05-1 Hz, and the responses persisted throughout 11-s static tilts. Th
ese data suggest that otolith organs activated by pitch influence acti
vity in the lumbar paravertebral muscles. These responses may serve to
stabilize the vertebral column during movements involving body pitch,
such as vertical climbing. (C) 1997 Elsevier Science Ireland Ltd.