Saccades to remembered targets exhibit enhanced orbital position effects in monkeys

Remembered saccades of rhesus monkeys are markedly influenced by starting e ye position. Altering the initial position systematically affects the direc tion or amplitude of the movements to a striking degree. In general, change s in the horizontal or vertical starting position primarily produce changes in the horizontal or vertical component, respectively, regardless of wheth er the target displacement occurs in the horizontal or vertical direction. For some monkeys, a similar pattern of initial position influence on moveme nt direction can be seen in the curvature of visually guided saccades. Star ting position also modulates the upward offset in fixation, which monkeys d isplay in the dark. (C) 2001 Elsevier Science Ltd. All rights reserved.