The relationship between marijuana use and BOLD signal changes was examined within the chronic, heavy marijuana smokers for both affective conditions. As seen in Figure 5a and Table 5, BOLD activity within the same posterior cingulate region noted as different between the marijuana smokers and controls during the viewing of masked angry faces was highly positively correlated with number of smokes (x, y, z = 12, −16, 34; t = 2.91, p< 0.05; k =25) per week; activity within the amygdala (Figure 5b) was not. For masked happy faces, no significant association was detected between cingulate activity and number of smokes per week (see Figure 6a), however, a significant positive correlation was noted for activity within the left amygdala and smokes per week (x, y, z = −18, −2, −22; t = 2.88, p< 0.05; k = 21; see Figure 6b, Table 5). This amygdalar activity was nearly identical to the region activated in healthy controls during the viewing of masked happy faces. A significant positive association was also detected for activity within the midcingulate during the viewing of masked
