Primary and secondary saccades to goals defined by instructions

A luminous point steps horizontally in the dark, and the subject tracks it (normal task), or is instructed to respond by some other horizontal eye movement (e.g. an equal and opposite movement — the “anti-saccade” task). Eye movements in the “anti-task” are characterized by long latency, inaccurate primary saccades which sometimes show minor anomalies in velocity profile. The secondary saccades are large, corrective, of shorter than primary...