Pontine Lesions May Cause Selective Deficits of “Slow” Vergence Eye Movements

Abstract

To address the role of pontine nuclei in vergence control, eye movements to ramp ('slow vergence') and step targets ('fast vergence') were recorded in two patients with unilateral mediolateral pontine infarctions and in ten healthy controls. 'Slow' vergence and conjugate smooth pursuit eye movements were impaired while 'fast' vergence was not. We conclude that like smooth pursuit signals, vergence signals are distributed in the pontine nuclei.