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|Event:||Ancillary Symposium entitled "Tightening The Genotype-Phenotype Gap: From Genetic Variation to Gene Function"|
|Location:||60th Annual Meeting of the American Society of Human Genetics (ASHG) at the Walter E. Washington Convention Center, 801 Mount Vernon Place, NW, Washigton, DC 20001-3614.|
|Start Date:||11/2/2010 8:00 AM|
|End Date:||11/2/2010 5:30 PM|
Adolescents with conduct and substance problems (“Antisocial Substance Disorder” (ASD)) repeatedly engage in risky antisocial and drug-using behaviors. We hypothesized that, during processing of risky decisions and resulting rewards and punishments, brain activation would differ between abstinent ASD boys and comparison boys.
We compared 20 abstinent adolescent male patients in treatment for ASD with 20 community controls, examining rapid event-related blood-oxygen-level-dependent (BOLD) responses during functional magnetic resonance imaging. In 90 decision trials participants chose to make either a cautious response that earned one cent, or a risky response that would either gain 5 cents or lose 10 cents; odds of losing increased as the game progressed. We also examined those times when subjects experienced wins, or separately losses, from their risky choices. We contrasted decision trials against very similar comparison trials requiring no decisions, using whole-brain BOLD-response analyses of group differences, corrected for multiple comparisons. During decision-making ASD boys showed hypoactivation in numerous brain regions robustly activated by controls, including orbitofrontal and dorsolateral prefrontal cortices, anterior cingulate, basal ganglia, insula, amygdala, hippocampus, and cerebellum. While experiencing wins, ASD boys had significantly less activity than controls in anterior cingulate, temporal regions, and cerebellum, with more activity nowhere. During losses ASD boys had significantly more activity than controls in orbitofrontal cortex, dorsolateral prefrontal cortex, brain stem, and cerebellum, with less activity nowhere.
Adolescent boys with ASD had extensive neural hypoactivity during risky decision-making, coupled with decreased activity during reward and increased activity during loss. These neural patterns may underlie the dangerous, excessive, sustained risk-taking of such boys. The findings suggest that the dysphoria, reward insensitivity, and suppressed neural activity observed among older addicted persons also characterize youths early in the development of substance use disorders.
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Alcohol is a commonly used social drug and driving under influence is a well-established risk factor for traffic accidents. To improve road safety, legal limits are set for blood alcohol concentration (BAC) and driving, usually at 0.05% (most European countries) or 0.08% (most US states, Canada and UK). Alcohol, even at these low concentrations, affects brain function and increases fall risk. An increased fall risk has been associated with impaired obstacle avoidance skills. Low level BACs are likely to affect obstacle avoidance reactions during gait, since the brain areas that are presumably involved in these reactions have been shown to be influenced by alcohol.
Therefore we investigated the effect of low to moderate alcohol consumption on such reactions. Thirteen healthy senior individuals were subjected to an obstacle avoidance task on a treadmill after low alcohol consumption. Fast stepping adjustments were required to successfully avoid suddenly appearing obstacles. Response times and amplitudes of the m. biceps femoris, a prime mover, as well as avoidance failure rates were assessed.
After the first alcoholic drink, 12 of the 13 participants already had slower responses. Without exception, all participants' biceps femoris response times were delayed after the final alcoholic drink.
The present results clearly show that even with BACs, considered to be safe for driving, obstacle avoidance reactions are inadequate, late, and too small. This is likely to contribute to an increased fall risk. Therefore we suggest that many of the alcohol-related falls are the result of the disruptive effects of alcohol on the online corrections of the ongoing gait pattern when walking under challenging conditions.
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The ISAJE/WHO Young Scholars Award aims to provide recognition for the contributions to addiction science of young scholars from low and middle income countries and to promote their involvement in the field. The award is given for the best paper published by a young scholar from a low or middle income country on any topic related to addiction. The winner will receive a certificate and financial support to attend an international scientific or clinical meeting in the addiction or substance abuse field, to be chosen by the winner in consultation with the Award Committee.
Applications are invited for the 2010 award. To be eligible, the paper must have been published either online or in print form in a peer-reviewed scholarly journal between 1 July 2007 and 30 June 2010. The research reported should have been carried out predominantly in a low or middle income country, as specified by the World Bank classification. Applicants must be less than 35 years old and should be the lead author in the paper being submitted for the award. They should hold a current academic or research position in a low or middle income country; or should have held such a position at the time the research for the paper was carried out. The deadline for receiving applications is 15 November 2010. > > > >