The exact test for binary independent measures [1] was used to produce significance maps (central hand in Fig. 1)
depicting the cells where group differences were statistically reliable. Due to the oriented hypotheses described previously, the alpha level was set to .05 unicaudal. The significancemaps resulting fromthe aforementioned comparisons were subsequently converted to binary values (0 = nonsignificant; 1 = significant), and a spatial scan procedure for binary data [46] was used, consisting of a circular window that scans the maps, detects, and localizes significant clusters in a stepwise fashion. Based on previous studies [26,27], the maximal radius was set at 6 cells (representing a maximal scanned surface of 113 cells).