Attentional control and brain metabolite levels in methamphetamine abusers.
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.
Salo
Ruth
R
Department of Psychiatry and Behavioral Sciences, University of California, Davis, California 95817 , USA. resalo@ucdavis.edu <resalo@ucdavis.edu>
Nordahl
Thomas E
TE
Natsuaki
Yutaka
Y
Leamon
Martin H
MH
Galloway
Gantt P
GP
Waters
Christy
C
Moore
Charles D
CD
Buonocore
Michael H
MH
D000328:Adult; D019969:Amphetamine-Related Disorders / Q000378:metabolism* / Q000523:psychology*; D001288:Attention / Q000187:drug effects*; D001923:Brain Chemistry / Q000187:drug effects*; D000697:Central Nervous System Stimulants; D002794:Choline / Q000378:metabolism; D003071:Cognition / Q000502:physiology; D003401:Creatine / Q000378:metabolism; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008694:Methamphetamine; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000187:drug effects; D011930:Reaction Time / Q000502:physiology; D012907:Smoking / Q000378:metabolism / Q000523:psychology; D014793:Visual Cortex / Q000187:drug effects / Q000378:metabolism
D000697:Central Nervous System Stimulants; D008694:Methamphetamine; D003401:Creatine; D002794:Choline