Glissadic overshoots are due to pulse width errors.

Abstract

Glissades are the slow, gliding eye movements often appended to the end of human saccadic eye movements. They have been used as an aid in diagnosing disease states, eg, multiple sclerosis and vascular lesions. Glissades are a consequence of a mismatch between the sizes of the pulse and step components of the pulse-step motoneuronal controller signals. This physiological and simulation study shows that glissadic overshoot is caused by pulse width errors and not by pulse height errors. This implies that the CNS can control the firing frequencies and recruitment of motoneurons more precisely than it can control the duration of the high-frequency motoneuronal saccadic burst.