Functional brain connectomes reflect acute and chronic cannabis use

Area of Science:

• Neuroscience
• Neuroimaging
• Cannabis Research

Background:

• Resting-state fMRI studies have examined Δ9-tetrahydrocannabinol (THC) effects on brain connectivity, often focusing on limited regions.
• Previous research has not comprehensively assessed cannabis's impact on whole-brain network organization.

Purpose of the Study:

• To investigate whole-brain functional connectome alterations in cannabis users using 7T resting-state fMRI.
• To differentiate connectivity changes associated with acute THC intoxication versus chronic cannabis use.

Main Methods:

• Utilized ultra-high field (7T) resting-state fMRI scans in 26 cannabis users under placebo and after THC vaporization.
• Employed network-based statistics (NBS) and connICA methodologies for data-driven analysis of functional connectomes.

Main Results:

• Both NBS and connICA identified widespread hyperconnectivity in chronic cannabis users compared to occasional users, indicative of adaptive reorganization.
• connICA revealed hypoconnectivity in attention, limbic, subcortical, and cerebellum networks, and hyperconnectivity between default mode and ventral attention networks during acute THC intoxication.
• Whole-brain analysis distinguished between acute and chronic cannabis use effects on functional brain connectomes.

Conclusions:

• Whole-brain network approaches are valuable for understanding short- and long-term functional brain dynamics related to cannabis use.
• Findings suggest that chronic cannabis exposure induces adaptive network reorganization, while acute intoxication presents distinct connectivity alterations.