Control of goal-directed movements: the contribution of orienting of visual attention and motor preparation

Three experiments investigated the role of attention and motor preparation for the control of goal-directed movements. In Experiment 1 (double step pa radigm), a movement correction was required on 25% of the trials towards th e left or right of the initial target. Within these 25% of trials, the prob ability of location of the second target was manipulated. The efficiency of movement control increased when increasing the probability of correcting t he movement in a given direction. In Experiment 2, attentional processes we re isolated by asking the subjects to verbally detect the more or less prob able target displacement, without correcting their movement. Subjects were able to orient visual attention during movement execution, thus improving t he processing of visual feedbacks from target displacement. In Experiment 3 , motor preparation processes were isolated by asking the subjects to corre ct their movement towards a fixed target in response to a more or less prob able mechanical perturbation. It was shown that motor preparation not only specifies the initial movement parameters but may also include some paramet ers of the most probable movement modulations. Overall, these results highl ight the role of both attentional and motor preparation processes in the co ntrol of goal-directed movements and suggest that the feedback-based correc tions of the movement are modulated by a feedforward control. (C) 1999 Else vier Science B.V. All rights reserved. PsycINFO classification: 2330; 2346.