A vestibulospinal pathway for context-dependent motor control of the mouse tail

Tail movement is critical for maintaining balance during locomotion in many animal species, yet its underlying neuromuscular control remains poorly understood. In this study, we investigate the neuronal substrates responsible for tail control in mice. Using high-resolution microCT and retrograde labeling, we describe the neuromuscular organization of the tail and identify distinct groups of motor neurons in the spinal cord that innervate proximal and distal muscles. We further show that the spinal vestibular nucleus in the brainstem sends projections to the spinal cord segments where tail motor neurons are located. Optogenetic activation of these vestibulospinal neurons results in tail movements during challenging balance tasks. Our results suggest that the influence of the vestibular system on tail movements may enhance balance performance under ambiguous sensory conditions. These findings provide insights into the neural circuits responsible for maintaining balance, highlighting the role of the vestibulospinal pathway in context-dependent modulation of tail movement.