RELATIONS BETWEEN ATTENTIONAL AND INTENTIONAL NEURAL SYSTEMS

This study explored whether preparing an arm movement influences detec tion of a visual stimulus. We cued subjects to respond with either a r ightward or a leftward movement to the appearance of a stimulus locate d either in the centre, in the left, or in the right visual field. Pro gramming a movement toward a lateral direction enhanced visual attenti on at that side. Rightward movements were associated with an attention al cost only for responses to a central location, while leftward movem ents slowed response latencies to both central and right-sided stimuli . We hypothesized that programming a rightward movement depends on the activation of intentional centers in either cerebral hemisphere. On t he contrary, leftward movements might be only driven by the contralate ral hemisphere.