Altered functional connectivity and oscillatory dynamics in polysubstance and cannabis only users during visuospatial...

Area of Science:

• Neuroscience
• Cognitive Science
• Addiction Research

Background:

• Cannabis use is linked to other psychoactive substance use and increased addiction risk.
• Neuroimaging studies on long-term cannabis effects are growing, but additive effects of polysubstance use remain understudied.

Purpose of the Study:

• To investigate the neural and functional connectivity differences between cannabis-only users and polysubstance users.
• To examine the impact of cannabis polysubstance use on visuospatial attention.

Main Methods:

• Magnetoencephalography (MEG) was used to record brain activity in 56 adults (polysubstance users, cannabis-only users, nonusers).
• A data-driven beamforming approach identified oscillatory neural responses during a visuospatial attention task.
• Whole-brain connectivity analyses were performed using identified cortical regions.

Main Results:

• Both cannabis-only and polysubstance users showed reduced occipital gamma responses during the pre-stimulus baseline compared to nonusers.
• Cannabis-only users exhibited weaker occipital theta responses than nonusers.
• Polysubstance users displayed significantly reduced beta connectivity between occipital and prefrontal/temporal cortices.

Conclusions:

• Cannabis use in a polysubstance context is associated with distinct functional connectivity alterations.
• Differences in occipital-prefrontal pathways highlight the importance of considering polysubstance use in visuospatial processing and attention.
• Future research should explore specific polysubstance combinations and employ causal designs.