Spatial modulation of vestibular reflexes by the cerebellum characterized in healthy volunteers and spinocerebellar ataxia patients

While maintaining balance appears effortless and relatively simple, it depends on a complex integration of sensory and motor signals that originate from a variety of sources in the body. When you turn your head, even though the vestibular organs of the inner ear change their orientation relative to the body, they still provide information which can be used to aid balance. This response relies on information received from vestibular organs (which measure linear and angular acceleration of the head) and sensory information from the neck (which conveys the head’s position). These two signals are then integrated to provide contextually specific directional information to the brain. As such, patients with damage to their vestibular organs tend to be posturally unstable. The cerebellum has emerged as a potential contributor to the convergence and interpretation of vestibular and somatosensory information in the brain. Patients with cerebellar dysfunction often exhibit similar abnormal balance behaviour to those with vestibular damage. Christopher Dakin is investigating the cerebellum’s role in the vestibular systems influence on balance. He is comparing postural responses associated with vestibular activation among two groups: healthy people, whose cerebellar function is temporarily inhibited by a technique called Transcranial magnetic stimulation; and individuals with spinocerebellar ataxia, a neurological disease marked by atrophy (wasting) of the cerebellum. By increasing our understanding of the human nervous system as it relates to cerebellar processing of vestibular information, Dakin’s research will contribute to more accurate balance disorder diagnoses and treatments. Ultimately, his work could lead to improved therapeutic and rehabilitative techniques directed towards patients with vestibulo-cerebellar dysfunction.