Attentional Control and Brain Metabolite Levels in Methamphetamine Abusers
Received 2 February 2006; received in revised form 11 July 2006; accepted 13 July 2006. published online 13 November 2006.
Background
Methamphetamine abuse is associated with neurotoxicity to frontostriatal brain regions with concomitant deleterious effects on cognitive processes.
Methods
By using a computerized measure of selective attention and single-voxel proton magnetic resonance spectroscopy, we examined the relationship between attentional control and brain metabolite levels in the anterior cingulate cortex (ACC) and primary visual cortex (PVC) in 36 currently abstinent methamphetamine abusers and 16 non–substance-using controls.
Results
The methamphetamine abusers exhibited reduced attentional control (i.e., increased Stroop interference) compared with the controls (p = .04). Bonferroni-adjusted comparisons revealed that ACC levels of N-acetyl aspartate (NAA)–creatine and phosphocreatine (Cr) were lower and that levels of choline (Cho)–NAA were higher in the methamphetamine abusers compared with the controls, at the adjusted p value of .0125. Levels of NAA-Cr, but not of Cho-NAA, within the ACC correlated with measures of attentional control in the methamphetamine abusers (r = −.41; p = .01) but not in controls (r = .22; p = .42). No significant correlations were observed in the PVC (methamphetamine abusers, r = .19; p = .28, controls, r = .38; p = .15).
Conclusions
Changes in neurochemicals within frontostriatal brain regions including ACC may contribute to deficits in attentional control among chronic methamphetamine abusers.
aDepartment of Psychiatry and Behavioral Sciences, University of California, Davis, California
bImaging Research Center, University of California, Davis, California
cDepartment of Radiology, University of California, Davis, California
dDepartment of Biomedical Engineering, University of California, Davis, California
eCalifornia Pacific Medical Center, San Francisco, California
fKaiser Chemical Dependence Recovery Program, Sacramento, California.
Address reprint requests to Ruth Salo, Ph.D., Imaging Research Center and Department of Psychiatry and Behavioral Sciences, University of California–Davis Medical Center, 4701 X Street, Sacramento, CA 95817
ABSTRACT