Location, location: using functional magnetic resonance imaging to pinpoint brain differences relevant to stimulant use.

AIMS: The purpose of this review is to summarize the neural substrate dysfunctions and disrupted cognitive, affective and experiential processes observed in methamphetamine and cocaine-dependent individuals.
METHODS: We reviewed all publications in PubMed that conducted comparison studies between healthy volunteers and cocaine-, amphetamine- or methamphetamine-dependent individuals using functional magnetic resonance imaging.
RESULTS: Stimulant dependence is characterized by a distributed alteration of functional activation to a number of experimental paradigms. Attenuated anterior and posterior cingulate activation, reduced inferior frontal and dorsolateral prefrontal cortex activation and altered posterior parietal activation point towards an inadequate demand-specific processing of information. Processes reported most consistently to be deficient in these functional neuroimaging studies include inhibitory control, executive functioning and decision-making.
CONCLUSION: One emerging theme is that stimulant-dependent individuals show specific, rather than generic, brain activation differences, i.e. instead of showing more or less brain activation regardless of task, they exhibit process-related brain activation differences that are consistent with a shift from context-specific, effortful processing to more stereotyped, habitual response generation.