Eye Movement Disorders;
Lesions of the cerebellum can result in a variety of eye movement disorders, including saccadic intrusions and oscillations, such as ocular dysmetria, as well as nystagmus, gaze palsies, and dysfunction of the vestibular ocular reflex. In this series of videos, these disorders are discussed in relation to the relevant cerebellar and brainstem anatomy. Further, a more detailed look at both nystagmus and how saccades are initiated and maintained is provided, with mention of the cerebellum’s role in these eye movements. Specifically, the origin of the pulse-step firing from the burst cells and nucleus prepositus hypoglossi, which is necessary to produce a saccade, as well as the tonic inhibition of the burst cells’ firing by the pause cells are detailed. Ocular flutter, a disorder of the pause cells, is used to illustrate these cells’ clinical significance.
KEYWORDS: cerebellar control of eye movements, nystagmus, upbeat nystagmus, downbeat nystagmus, Alexander’s Law, burst cells, nucleus prepositus hypoglossi, pause cells, nucleus raphe interpositus, ocular palatal myoclonus, ocular dysmetria, ocular flutter
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Robert B. Daroff, MD, Professor of Neurology, School of Medicine, CASE Western Reserve University, University Hospitals - Case Medical Center
Spencer S. Eccles Health Sciences Library, University of Utah