Home > A validation of event-related fMRI comparisons between users of cocaine, nicotine, or cannabis and control subjects.

Murphy, Kevin and Dixon, Veronica and LaGrave, Kathleen and Kaufman, Jacqueline and Risinger, Robert and Bloom, Alan and Garavan, Hugh (2006) A validation of event-related fMRI comparisons between users of cocaine, nicotine, or cannabis and control subjects. American Journal of Psychiatry , 163 , (7) , pp. 1245-1251.

URL: http://ajp.psychiatryonline.org/cgi/content/full/1...

OBJECTIVE: Noninvasive brain imaging techniques are a powerful tool for researching the effects of drug abuse on brain activation measures. However, because many drugs have direct vascular effects, the validity of techniques that depend on blood flow measures as a reflection of neuronal activity may be called into question. This may be of particular concern in event-related functional magnetic resonance imaging (fMRI), where current analytic techniques search for a specific shape in the hemodynamic response to neuronal activity.

METHOD: To investigate possible alterations in task-related activation as a result of drug abuse, fMRI scans were conducted on subjects in four groups as they performed a simple event-related finger-tapping task: users of cocaine, nicotine, or cannabis and control subjects.

RESULTS: Activation measures, as determined by two different analytic methods, did not differ between the groups. A comparison between an intravenous saline and an intravenous cocaine condition in cocaine users found a similar null result. Further in-depth analyses of the shape of the hemodynamic responses in each group also showed no differences.

CONCLUSIONS: This study demonstrates that drug groups may be compared with control subjects using event-related fMRI without the need for any post hoc procedures to correct for possible drug-induced cardiovascular alterations. Thus, fMRI activation differences reported between these drug groups can be more confidently interpreted as reflecting neuronal differences.

 

Item Type:Article
Date:2006
Page Range:pp. 1245-1251
Publisher:American Psychiatric Association
Volume:163
Number:7
Keywords:Cannabis, cocaine, Ireland, nervous system diagnosis, neuroimaging, nicotine
EndNote:View
Accession Number:HRB 4142 (Electronic Only)
Subjects:HA Screening, identification, and diagnostic method > Medical screening and diagnostic method
B Substances > Cocaine
B Substances > Cannabis / Marijuana
A Substance use, abuse, and dependence > Theory of substance use > Biological substance use disorder theory
E Concepts in biomedical areas > General life processes (physiology)
B Substances > Tobacco (cigarette smoking)

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