Fig. 4.

Between-groups (Pre-HDs - Controls) comparison of activity evoked by mental rotation. A) Mental rotation (80° – 0°) evoked a larger (more negative) response in healthy controls relative to Pre-HD individuals within early visual areas, centered anteriorly relative to borders of the primary visual area (V1; [50]). The activity map (p-values) is corrected for multiple comparison. B) Border of regions of interest, defined based on subjects’ own high-resolution structural scans (i.e., defined independently from the functional responses), overlaid on an average inflated brain. Red and cyan outlines indicate ROIs that showed a higher and lower activity during mental rotation compared to not rotated trials, respectively. C) BOLD activity measured within cortical regions-of-interest (ROIs) of Pre-HDs (green) and healthy matched controls (red) across different mental rotation conditions relative to 0° trials. Consistent with the activity maps, impaired mental rotation related activity was found within early visual areas. However, this sensitive test also showed impaired activity within superior frontal cortex and orbitofrontal cortex of Pre-HDs relative to controls (Table 2). Error bars show one standard error of mean.