Brain imaging study of the acute effects of Delta9-tetrahydrocannabinol (THC) on attention and motor coordination in regular users of marijuana.
METHODS
Twelve regular users of marijuana underwent two positron emission tomography (PET) scans using [18F] Fluorodeoxyglucose (FDG), one while subject to the effects of 17 mg THC, the other without THC. In both sessions, a virtual reality maze task was performed during the FDG uptake period.


RESULTS
When subject to the effects of 17 mg THC, regular marijuana smokers hit the walls more often on the virtual maze task than without THC. Compared to results without THC, 17 mg THC increased brain metabolism during task performance in areas that are associated with motor coordination and attention in the middle and medial frontal cortices and anterior cingulate, and reduced metabolism in areas that are related to visual integration of motion in the occipital lobes.


CONCLUSIONS
These findings suggest that in regular marijuana users, the immediate effects of marijuana may impact on cognitive-motor skills and brain mechanisms that modulate coordinated movement and driving.
Weinstein
Aviv
A
Department of Nuclear Medicine, Sourasky Medical Center, Tel Aviv, Israel. vaviv@hadassah.org.il
Brickner
Orit
O
Lerman
Hedva
H
Greemland
Mazal
M
Bloch
Miki
M
Lester
Hava
H
Chisin
Roland
R
Mechoulam
Raphael
R
Bar-Hamburger
Rachel
R
Freedman
Nanette
N
Even-Sapir
Einat
E
D001288:Attention / Q000187:drug effects*; D001786:Blood Glucose / Q000378:metabolism*; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000187:drug effects*; D013759:Dronabinol / Q000494:pharmacology*; D019788:Fluorodeoxyglucose F18; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000187:drug effects; D006179:Gyrus Cinguli / Q000000981:diagnostic imaging / Q000187:drug effects; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D002189:Marijuana Abuse / Q000000981:diagnostic imaging*; D018782:Maze Learning / Q000187:drug effects; D011939:Mental Recall / Q000187:drug effects; D009483:Neuropsychological Tests; D009778:Occipital Lobe / Q000000981:diagnostic imaging / Q000187:drug effects; D049268:Positron-Emission Tomography; D011597:Psychomotor Performance / Q000187:drug effects*; D014057:Tomography, X-Ray Computed; D014584:User-Computer Interface
D001786:Blood Glucose; D019788:Fluorodeoxyglucose F18; D013759:Dronabinol