The volitional inhibition of anticipatory ocular pursuit using a stop signal.

Unlike limb movements, smooth pursuit eye movements cannot normally be performed in the absence of a target. However, when subjects have a high expectancy of an imminent target appearance, the situation changes, and anticipatory smooth pursuit (ASP) tends to precede target onset by several hundred milliseconds. The velocity of this ASP is scaled predictively according to expected target velocity.

Volitional scaling of anticipatory ocular pursuit velocity using precues.

Human subjects cannot normally perform smooth eye movements in the absence of a target. However, the repeated presentation of identical, transient target motion stimuli, preceded by warning cues, leads to the build up of anticipatory smooth pursuit (ASP) eye movements several hundred milliseconds prior to stimulus onset. The present study sought to investigate whether subjects are able to volitionally scale ASP speed, as well as select pursuit direction, in advance of target motion stimuli of random direction (left vs.