Balance Control Mediated by Vestibular Circuits Directing Limb Extension or Antagonist Muscle Co-activation

• Published in: Cell reports (Cambridge) 2018-01, Vol.22 (5), p.1325-1338
• Main Authors: Murray, Andrew J., Croce, Katherine, Belton, Timothy, Akay, Turgay, Jessell, Thomas M.
• Format: Article
• Language: English
• Subjects: balance control; lateral vestibular nucleus; motor transition; neural circuits; neuronal diversity; postural control; vestibular system
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2018.01.009

Maintaining balance after an external perturbation requires modification of ongoing motor plans and the selection of contextually appropriate muscle activation patterns that respect body and limb position. We have used the vestibular system to generate sensory-evoked transitions in motor programming. In the face of a rapid balance perturbation, the lateral vestibular nucleus (LVN) generates exclusive extensor muscle activation and selective early extension of the hindlimb, followed by the co-activation of extensor and flexor muscle groups. The temporal separation in EMG response to balance perturbation reflects two distinct cell types within the LVN that generate different phases of this motor program. Initially, an LVNextensor population directs an extension movement that reflects connections with extensor, but not flexor, motor neurons. A distinct LVNco-activation population initiates muscle co-activation via the pontine reticular nucleus. Thus, distinct circuits within the LVN generate different elements of a motor program involved in the maintenance of balance. [Display omitted] •Lateral vestibular nucleus (LVN) is required for fast responses to postural perturbation•After perturbation, an early activated LVN cell type activates extensor motor neurons•A later activated cell type generates a hind limb muscle co-contraction•These non-overlapping cell types produce a coordinated response to balance perturbation Murray et al. study how the nervous system generates an appropriate motor response following a postural perturbation. They identify two distinct cell types in the lateral vestibular nucleus that act together to maintain posture when a mouse undergoes a perturbation on a balance beam.