Regular cannabis use is associated with weaker spontaneous gamma oscillations in the left primary motor cortex, but not with differences in oscillatory beta or gamma activity. The study compared 34 regular cannabis users and 33 nonusers performing a motor control task during magnetoencephalography. The cannabis group showed suppressed spontaneous gamma activity that scaled with cannabis use disorder symptoms and behavioral performance. No group differences appeared in spontaneous beta activity.
Regular cannabis use is linked to suppressed spontaneous gamma brain activity in regions that support cognitive control, specifically the left frontal eye fields (FEF) and left temporoparietal junction (TPJ). In a study of 34 cannabis users and 33 nonusers performing a flanker task during magnetoencephalography, cannabis users showed no difference in gamma oscillations between incongruent and congruent trials, whereas nonusers exhibited stronger gamma during incongruent trials. Spontaneous gamma activity was sharply reduced in cannabis users in both brain regions, and greater cannabis use was associated with weaker spontaneous gamma activity in the left TPJ. These findings suggest that regular cannabis use dampens baseline gamma activity in cognitive control networks, and the degree of suppression may scale with the amount of use.