During the viewing of angry faces, non-marijuana smoking control subjects demonstrated significant differences relative to the chronic, heavy marijuana smokers (see Table 3). Greater activation was evident within an area of the midanterior cingulate relative to the marijuana smokers (peak x, y, z = 6, 18, 36; t = 3.58, p#x0003C; 0.05; k = 753; see Figure 1a). In contrast, the chronic, heavy marijuana smokers demonstrated much lower and more posterior cingulate activity than the non-marijuana smoking control subjects during the viewing of angry faces (peak x, y, z = −16, −12, 34; t = 3.23, p< 0.05; k = 41; see Figure 1b, Table 3). During the same condition, the control subjects exhibited activity within the left amygdala relative to the marijuana smokers (peak x, y, z = −20, −c4, −14; t = 2.32, p< 0.05; k = 35; see Figure 2a), who in contrast, showed no area of increased activation relative to the control subjects within the amygdala (see Figure 2b).
