Acute marijuana effects on rCBF and cognition: a PET study

The effects of smoking marijuana on cognition and brain function were asses sed with PET using (H2O)-O-15. Regional cerebral blood flow (rCBF) was meas ured in five recreational users before and after smoking a marijuana cigare tte, as they repeatedly performed an auditory attention task. Blood flow in creased following smoking in a number of paralimbic brain regions (e.g. orb ital frontal lobes, insula, temporal poles) and in anterior cingulate and c erebellum Large reductions in rCBF were observed in temporal lobe regions t hat are sensitive to auditory attention effects. Brain regions showing incr eased rCBF may mediate the intoxicating and mood-related effects of smoking marijuana, whereas reduction of task-related rCBF in temporal lobe cortice s may account for the impaired cognitive functions associated with acute in toxication. NeuroReport 11:3835-3841 (C) 2000 Lippincott Williams & Wilkins .