Figure 5.

Hypotheses and controls to explain the presence of ipsilesional deficits. A, Standard spatial configuration of the items for the two-, four-, and eight-item conditions. Two contrasting hypotheses to explain the deficit in the eight-item condition are illustrated: according to a spatial hypothesis, the region of visual space affected by FEF inactivation (gray area) could include a portion of the ipsilateral field; according to the directional hypothesis, the speed or probability of contraversive shifts of attention (gray arrow) are diminished compared with ipsiversive shifts (black arrow; gray area). B, C, FEF inactivation effect on the detection of a contralesional target (top part) and an ipsilateral target (bottom part) when all items are vertically aligned at 7 and at 3.5° of eccentricity, respectively. Conventions are the same as those in Figure 1.