SPATIAL ATTENTION-DETERMINED MODIFICATIONS IN SACCADE TRAJECTORIES

NORMAL subjects were required to make horizontal or vertical saccades at the presentation of visual or acoustic imperative stimuli. The loca tions of visual imperative stimuli were orthogonal to the required sac cade. Before stimulus presentation the subjects were cued about its lo cation and instructed to allocate attention to it without moving the e yes. The main aim of the experiment was to establish whether the traje ctory of horizontal saccades would be modified by spatial attention. T he results showed that, with respect to the condition in which attenti on was on the horizontal meridian, the allocation of attention to the upper hemifield determined a downward saccade deviation, while the all ocation to the lower hemifield determined an opposite deviation. The d ata strongly support the view that spatial attention and saccade progr amming share the same neural substrates.