The Dual Roles of Vestibulospinal Reflexes: Excitatory and Inhibitory Influences on Limb Muscle Activity

Vestibular pathways project to multiple levels of the brainstem and spinal cord, significantly influencing motoneuron activity and playing a central role in postural control and the coordination of head and eye movements. Emerging evidence suggests that vestibulospinal signaling may also project broadly to upper limb motoneurons in able-bodied individuals and may contribute to abnormal muscle coactivation and motor impairments in the upper limbs of stroke survivors. However, vestibulospinal influences on upper limb muscles remain poorly understood, highlighting the need to clarify their role. In this presentation, I will discuss how vestibular-evoked responses elicited through electrical and acoustic stimulation modulate spinal reflexes and muscle activation in both the upper and lower limbs.