Chronic cannabis use is linked to altered coordination between visual brain regions and the ventral attention network during cognitive flexibility tasks. Twenty-five chronic users and 30 non-users completed a task-switch paradigm while undergoing magnetoencephalography. Users showed modified associations between functional connectivity switch costs and behavioral switch costs along pathways connecting visual cortices and attention-related regions, within theta, alpha, and gamma frequency ranges. These findings indicate that cannabis use is associated with changes in how brain networks communicate during tasks requiring cognitive flexibility, particularly involving visual and executive function areas.
Heavy cannabis users show weaker alpha brain oscillations during the encoding phase of a working memory task, particularly in superior parietal and occipital regions, compared to nonusers. During memory maintenance, a group-by-condition interaction emerged: cannabis users exhibited weaker alpha and beta oscillations during maintain trials but stronger oscillations in the same regions during manipulate trials, alongside prolonged reaction times. Nonusers showed no such differences. Neurobehavioral relationships in prefrontal cortices appeared only in nonusers. Chronic cannabis use may impair initial memory encoding but prompt compensatory neural activity during more demanding memory manipulation.
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.