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Higher Cortical and Lower Subcortical Metabolism in Detoxified Methamphetamine Users (2001)

Higher Cortical and Lower Subcortical Metabolism in Detoxified Methamphetamine Users (2001)

  1. Jatelka
    American Journal of Psychiatry 2001; 158:383–389

    Volkow et al

    Objective: Methamphetamine has raised concerns because it may be neurotoxic to the human brain. Although prior work has focused primarily on the effects of methamphetamine on dopamine cells, there is evidence that other neuronal types are affected. The authors measured regional brain glucose metabolism, which serves as a marker of brain function, to assess if there is evidence of functional changes in methamphetamine abusers in
    regions other than those innervated by
    dopamine cells.
    Method: Fifteen detoxified methamphetamine abusers and 21 comparison subjects underwent positron emission tomography following administration of [18F]fluorodeoxyglucose.
    Results: Whole brain metabolism in the methamphetamine abusers was 14% higher than that of comparison subjects; the differences were most accentuated in the parietal cortex (20%). After normalization for whole brain metabolism, methamphetamine abusers exhibited significantly
    lower metabolism in the thalamus (17% difference) and striatum (where the differences were larger for the caudate [12%] than for the putamen [6%]). Statistical parametric mapping analyses corroborated these findings, revealing higher
    metabolism in the parietal cortex and lower metabolism in the thalamus and striatum of methamphetamine abusers.
    Conclusions: The fact that the parietal cortex is a region devoid of any significant dopaminergic innervation suggests that the higher metabolism seen in this region in the methamphetamine abusers is the result of methamphetamine effects in circuits other than those modulated by dopamine. In addition, the lower metabolism
    in the striatum and thalamus (major outputs of dopamine signals into the cortex) is likely to reflect the functional consequence of methamphetamine in dopaminergic circuits. These results provide evidence that, in humans, methamphetamine abuse results in changes in
    function of dopamine- and nondopamine- innervated brain regions.