Cannabis use among people with HIV (PWH) is associated with stronger gamma oscillations during a somatosensory gating task, suggesting a potential protective effect on inhibitory neural processing. In a cross-sectional study of 108 participants (cannabis users and non-users with and without HIV), PWH who used cannabis showed elevated oscillatory gamma activity in the primary somatosensory cortex compared to PWH who did not use cannabis, who also exhibited elevated spontaneous gamma activity. Longer time since HIV diagnosis correlated with less efficient inhibitory processing only in PWH who did not use cannabis, indicating regular cannabis use may mitigate HIV-related neural deficits.
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.