Effects of Visual Error Timing on Smooth Pursuit Gain Adaptation in Humans.

Smooth pursuit (SP) is one of the precise oculomotor behaviors when tracking a moving object. Adaptation of SP is based on a visual-error driven motor learning process associated with predictable changes in the visual environment. Proper timing of a sensory signal is an important factor for adaptation of fine motor control. In this study, we investigated whether visual error timing affects SP gain adaptation. An adaptive change in SP gain is produced experimentally by repeated trials of a step-ramp tracking with 2 different velocities (double-velocity paradigm). The authors used the double-velocity paradigm where target speed changes 400 or 800 ms after the target onset. The results show that SP gain changed in a certain time window following adaptation. The authors suggest that SP adaptation shown in this study is associated with timing control mechanisms.