title: Balanced modulation of striatal activation from D2 /D3 receptors in caudate and ventral striatum: Disruption in cannabis abusers.
abstract: Proper communication between dorsal caudate (CD) and ventral striatum (VS) is likely to be crucial for on-time responses and its disruption might result in impulsivity. Here, we used functional magnetic resonance imaging (fMRI) with a sensorimotor reaction time task and positron emission tomography (PET) with [(11)C]raclopride in 14 healthy controls and 18 cannabis abusers to contrast the modulation of striatal fMRI responses by dopamine receptors (D2 /D3 R) in CD and VS. In controls, we show that the fMRI signals in VS that occurs concomitantly with on-time responses showed opposite modulation from D2 /D3 R in CD (inhibitory) and D2 /D3 R in VS (stimulatory). In contrast, this modulation was not significant in cannabis abusers. Findings suggest that action speed requires balanced VS-inhibition from D2 /D3 R in CD and VS-facilitation from D2 /D3 R in VS.
authors.affiliation: National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, 20892.
authors.forename: Dardo
authors.initials: D
authors.lastname: Tomasi
authors.affiliation: National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, 20892.
authors.forename: Gene-Jack
authors.initials: GJ
authors.lastname: Wang
authors.affiliation: National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, 20892.|National Institute on Drug Abuse, National Institutes of Health, Bethesda, Maryland, 20892.
authors.forename: Nora D
authors.initials: ND
authors.lastname: Volkow
mesh_terms: D000328:Adult; D001931:Brain Mapping; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology*; D018492:Dopamine Antagonists; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D002189:Marijuana Abuse / Q000000981:diagnostic imaging / Q000503:physiopathology*; D049268:Positron-Emission Tomography; D011597:Psychomotor Performance / Q000187:drug effects / Q000502:physiology*; D020891:Raclopride; D019275:Radiopharmaceuticals; D011930:Reaction Time; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D050637:Receptors, Dopamine D3 / Q000378:metabolism*
chemical_list: D018492:Dopamine Antagonists; D019275:Radiopharmaceuticals; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D020891:Raclopride
keywords: dopamine; functional magnetic resonance imaging; positron emission tomography; raclopride; reaction time; reward; sensorimotor