Module 5
The brainstem hub of balance — the four vestibular nuclei, the tracts that carry their output to the eyes, spinal cord, and cortex, and what goes wrong with central vestibular lesions.
The vestibular nuclei are the central processing hub of the balance system — a complex of four nuclei in the brainstem, at the pontomedullary junction, where peripheral signals are received and acted on.3
From the nuclei, three broad streams of output leave the brainstem: to the eyes, to the spinal cord, and upward to the thalamus and cortex.3
The vestibular nuclei work in close partnership with the cerebellum, which constantly tunes and corrects their output to keep reflexes accurate.46
A lesion of the central vestibular structures — the nuclei or their tracts — produces vertigo, imbalance, and nystagmus, but with features that distinguish it from a peripheral cause.62