Marijuana alters the human cerebellar clock.
Daniel S O'Leary, Robert I. Block, Beth M Turner, Julie Koeppel, Vincent A Magnotta, Laura L. Boles Ponto, G Leonard Watkins, Richard D Hichwa, Nancy C Andreasen
Neuroreport June 11, 2003 DOI: 10.1097/00001756-200306110-00009 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort Peer reviewed |
|---|---|
| Sample size | 24 |
| Population | Occasional and chronic marijuana smokers |
| Intervention | Marijuana |
| Topics | Cannabis |
| Key findings | Smoking marijuana increased rCBF in the ventral forebrain and cerebellar cortex in both occasional and chronic users, but chronic users showed less frontal lobe activation. Counting and tapping rates increased after marijuana, correlating with cerebellar rCBF, suggesting marijuana accelerates a cerebellar clock. |
Abstract
The effects of marijuana on brain perfusion and internal timing were assessed using [15O] water PET in occasional and chronic users. Twelve volunteers who smoked marijuana recreationally about once weekly, and 12 volunteers who smoked daily for a number of years performed a self-paced counting task during PET imaging, before and after smoking marijuana and placebo cigarettes. Smoking marijuana increased rCBF in the ventral forebrain and cerebellar cortex in both groups, but resulted in significantly less frontal lobe activation in chronic users. Counting rate increased after smoking marijuana in both groups, as did a behavioral measure of self-paced tapping, and both increases correlated with rCBF in the cerebellum. Smoking marijuana appears to accelerate a cerebellar clock altering self-paced behaviors.