Article
Muscle-specific modulation of vestibular reflexes with increased locomotor velocity and cadence
Journal of Neurophysiology
(2013)
Abstract
Muscle-specific modulation
of vestibular reflexes with increased locomotor velocity and
cadence. J Neurophysiol 110: 86–94, 2013. First published April 10,
2013; doi:10.1152/jn.00843.2012.—Vestibular information is one of
the many sensory signals used to stabilize the body during locomotion.
When locomotor velocity increases, the influence of these signals
appears to wane. It is unclear whether vestibular signals are globally
attenuated with velocity or are influenced by factors such as whether
a muscle is contributing to balance control. Here we investigate how
vestibular sensory signals influence muscles of the leg during locomotion
and what causes their attenuation with increasing locomotor
velocity. We hypothesized that 1) vestibular signals influence the
activity of all muscles engaged in the maintenance of medio-lateral
stability during locomotion and 2) increases in both cadence and
velocity would be associated with attenuation of these signals. We
used a stochastic vestibular stimulus and recorded electromyographic
signals from muscles of the ankle, knee, and hip. Participants walked
using two cadences (52 and 78 steps/min) and two walking velocities
(0.4 and 0.8 m/s). We observed phase-dependent modulation of
vestibular influence over ongoing muscle activity in all recorded
muscles. Within a stride, reversals of the muscle responses were
observed in the biceps femoris, tibialis anterior, and rectus femoris.
Vestibular-muscle coupling decreases with increases in both cadence
and walking velocity. These results show that the observed vestibular
suppression is muscle- and phase dependent. We suggest that the
phase- and muscle-specific influence of vestibular signals on locomotor
activity is organized according to each muscle’s functional role in
body stabilization during locomotion.
Keywords
- vestibular signal; locomotion; stochastic stimulus; reflex reversal
Disciplines
Publication Date
April 10, 2013
Citation Information
Chris Dakin. "Muscle-specific modulation of vestibular reflexes with increased locomotor velocity and cadence" Journal of Neurophysiology Vol. 110 (2013) p. 86 - 94 Available at: http://works.bepress.com/chris-dakin/1/