Some Aspects of the Motor Organization of the Oculomotor System

Oculomotor responses in looking to visual targets were examined for motor coordination parallel to that found in manual pointing. Ocular responses did not show any evidence of speed-accuracy tradeoff when the correlation of latency (reaction time) and accuracy was assessed. The oculomotor system did show a range effect, hidden under a general undershoot of target position and present only when no visual feedback about target position was available to allow correction during the movement. Cues to allow predictive timing of the response seemed very important for oculomotor reaction time. Processing of timing of movement may be handled differently for oculomotor than for manual orienting, and calculation of position in space may be processed in common, leading to both similarities and differences for the two motor systems.