The whole brain data, while exploratory, were not constrained by a prioi hypothesized regional analyses, yet still demonstrated a robust difference between the groups for each of the task conditions. During the viewing of masked angry faces, the non-marijuana smoking control subjects demonstrated significant activation within nearly the same region of the cingulate demonstrated in the ROI analyses, suggesting that this region is important for the processing of masked angry stimuli. The chronic, heavy marijuana smokers did not exhibit the same pattern of activity as the non-marijuana smokers, and in fact appeared to activate posterior and temporal regions for both masked affective tasks in the whole brain analyses, perhaps underscoring the notion of a compensatory process at work in these subjects. It is of note, however, that despite the regional differences seen for both groups during the tasks, each group activated significant numbers of voxels, which, while distributed differently, argues against a global reduction in activation during the tasks for either group.
