OBLIQUE MISDIRECTION AND SLOWING OF VERTICAL SACCADES AFTER UNILATERAL LESIONS OF THE PONTINE TEGMENTUM

Three patients with unilateral lesions of the pontine tegmentum, ident ified by CT and MRI, had abnormal vertical saccades and slowed ipsilat eral horizontal saccades. Attempted vertical saccades were misdirected obliquely, away from the side of the lesion, and their vertical compo nents were prolonged. Oblique saccades had curved trajectories and pro longed durations of their vertical components. Unilateral damage to ex citatory burst neurons and pause cells in the medial part of the cauda l paramedian pontine reticular formation may cause these abnormal vert ical and oblique saccades. Misdirection and slowing of vertical saccad es can accompany the paralysis or slowing of ipsilateral horizontal sa ccades caused by pontine damage.