COGNITIVE AND NEURAL MECHANISMS OF DECISION MAKING

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The overall aim of this project is to assess the neurocognitive mechanisms of judgement and decision-making that may be impaired in recreational MDMA ("Ecstasy") users, and the relationship of these defective mechanisms to the complex strategical and tactical decision-making operations needed to safely drive a motor vehicle. the widespread use of Ecstasy by young people causes concern, especially due to its associated risk of traffic accidents. Epidemiological research and case studies have shown that impaired judgement and higher risk taking are the most likely contributors to Ecstasy-related traffic accidents. Research also shows that there is a link between recreational Ecstasy use, possible serotonin neurotoxicity, decline in decision-making, impulse control, and other mechanisms of executive functions, and a potential impact on driving behavior. These problems seem to remain long after the recreational use of Ecstasy has ceased, suggesting that the neuropharmacological damage may be long lasting or permanent. Although the residual cognitive effects of Ecstasy have been studied extensively in drug free Ecstasy users, these studies have focused primarily on mechanisms of memory, divided attention, semantic recognition, verbal reasoning and learning. Very little is known about how Ecstasy impacts directly the mechanisms of judgement/decision-making, working memory, and impulse control, in abstinent users. Therefore, this study will test a series of hypotheses on cognition and driving behavior in Ecstasy users. The overall hypothesis is that recreational use of MDMA, and to a lesser extent other drugs (e.g. cannabis), will produce residual cognitive effects that in turn result in errors in judgement during the driving task. These errors in judgement are directly related to decline in specific executive functions as measured by neuropsychological tests of frontal lobe functions. Elucidation of the residual effects of Ecstasy on judgement, decision-making, and impulse control has several important practical consequences, in addition to its obvious value in advancing fundamental knowledge in cognitive neuroscience.