Figure 9.

Segregation of shift signals compared with stay and stimulus representation signals. Top, FreeSurfer F99 inflated and flattened surfaces (LH, left hemisphere; RH, right hemisphere), displaying activation of the stimulus representation (from separate localizer experiment) obtained with the same contrast as in Figures 3 and 7 (green), but at virtually unthresholded level (hot color, t ≥ 0.02). The majority of areas activated by contralateral attention (white outlines, same as hot color in Fig. 3) overlaps with the stimulus representation, opposed to areas modulated by attention shifts (yellow outlines, same as hot color in Fig. 7), clustering outside the activated areas. Black outlines indicate the same as white outlines of retinotopic areas in Figures 3 and 7. Blue panel, PSC of localizer data within the stay-right selective ROIs in the left hemisphere. Red panel, PSC of localizer data within stay-left selective ROIs in the right hemisphere (same ROIs/numbers as in Figs. 3, 4, 5, 6). The stimulus is represented in all areas driven by contralateral attention, except in the ACC and SEF/F7 and the caudate nucleus, and much less so in subcortical areas. *p < 0.05 (t test, Bonferroni corrected for n = 14). Black panel, Shift-selective areas (same ROIs/numbers as in Figs. 7, 11, 12) are not driven by the stimulus localizer, except for left and right areas 46. *p < 0.05 (t test, Bonferroni corrected for n = 12). Bar plots represent conditions of the stimulus localizer experiment: (1) left unilateral, (2) right unilateral, and (3) bilateral stimulus display versus fixation (see Materials and Methods).