Addiction biology
February 1, 2025
Kellen M McDonald, Mikki Schantell, Jason A John et al.
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.
Neurobiology of disease
February 1, 2025
Peihan J Huang, Jake J Son, Yasra Arif et al.
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.
Brain communications
January 1, 2025
Mikki Schantell, Mia C Lulli, Kellen M McDonald et al.
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.
Journal of psychopharmacology (Oxford, England)
August 1, 2024
Camilo A Castelblanco, Seth D Springer, Mikki Schantell et al.
Chronic cannabis users show altered brain oscillations during visuospatial processing. Compared to non-users, regular users had weaker theta oscillations in occipital and cerebellar regions and weaker gamma responses in left temporal cortices. Alpha oscillations did not differ, but alpha connectivity among higher-order attention areas was weaker in users and correlated with performance. These results suggest chronic cannabis use is associated with changes in neural dynamics and connectivity supporting visuospatial attention, potentially reflecting compensatory activity or early aberrant dynamics.
Human brain mapping
August 1, 2024
Mikki Schantell, Jason A John, Anna T Coutant et al.
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.