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Nick F. Ramsey

2 papers in the library · publishing 2019-2021

Papers

Task-independent acute effects of delta-9-tetrahydrocannabinol on human brain function and its relationship with cannabinoid receptor gene expression: a neuroimaging meta-regression analysis

bioRxiv (Cold Spring Harbor Laboratory) November 3, 2021 Brandon Gunasekera, Cathy Davies, Grace Blest‐hopley et al. preprint

A single dose of delta-9-tetrahydrocannabinol (THC) alters brain activation signals in a widespread network of regions, with some areas showing increased and others decreased activity. The magnitude of these changes is directly related to the local expression of the cannabinoid type-1 (CB1) receptor, but not the type-2 (CB2) receptor. THC increased activation in the anterior cingulate, superior frontal cortices, middle temporal and occipital gyri, striatum, amygdala, thalamus, and cerebellum crus II, while decreasing it in the middle temporal gyrus, superior temporal gyrus, angular gyrus, precuneus, cuneus, inferior parietal lobule, and cerebellum lobule IV/V. A dose-response relationship was observed in certain brain regions.

Acute effects of ∆9-tetrahydrocannabinol (THC) on resting state brain function and their modulation by COMT genotype.

European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology June 1, 2019 Matthijs G. Bossong, Hendrika H Van Hell, Chris D Schubart et al.

A single dose of THC, the main psychoactive ingredient in cannabis, increases blood flow (perfusion) in brain regions linked to the salience network—the bilateral insula, medial superior frontal cortex, and left middle orbital frontal gyrus—while decreasing connectivity between that last area and the precuneus. The perfusion increase in the left insula correlated with subjective changes in perception and relaxation. Genetic variation in the COMT Val158Met genotype modulated these effects: only Val/Met heterozygotes showed increased perfusion in the executive network after THC, suggesting that prefrontal dopamine levels influence susceptibility to cannabis's acute effects.