Choosing and implementing the rules for contextually adequate behavior depends on frontostriatal interactions. Observations in Parkinson's disease and pharmacological manipulations of dopamine transmission suggest that these corticobasal loops are modulated by dopamine. To determine, therefore, the physiological contributions of dopamine to task-rule-related processing, we performed a cue-targe...

OBJECTIVE In obsessive-compulsive disorder (OCD), symmetry-related symptoms may be important. Although clinical correlates of symmetry-related symptoms have been identified in OCD, few data exist on genetic associations. Animal studies indicate involvement of dopamine in symmetry-related behavior, suggesting this may be relevant to analogous symptoms in OCD. Alterations in dopamine may also ref...

Individual participants vary greatly in their ability to estimate and discriminate intervals of time. This heterogeneity of performance may be caused by reliance on different time perception networks as well as individual differences in the activation of brain structures utilized for timing within those networks. To address these possibilities we utilized event-related functional magnetic reson...

OBJECTIVES Studies of mania risk have increasingly relied on measures of subsyndromal tendencies to experience manic symptoms. The measures of mania risk employed in those studies have been shown to predict manic onset, to show familial associations, and to demonstrate expected correlations with psychosocial variables related to bipolar disorder. However, little work has been conducted to valid...

s | 87 the studied polymorphisms via the restriction fragment length polymorphism method. Clinical factors such as gender, age, duration of illness, and final medication dosage were noted as well. The researchers measured psychopathology biweekly, using the Positive and Negative Syndrome Scale (PANSS) fivefactor model scale (positive, negative, excitement, cognitive, and depressive). A mixed mo...

BACKGROUND While the heritability of cigarette smoking and nicotine dependence (ND) is well-documented, the contribution of specific genetic variants to specific phenotypes has not been closely examined. The objectives of this study were to test the associations between 321 tagging single-nucleotide polymorphisms (SNPs) that capture common genetic variation in 24 genes, and early smoking and ND...

PURPOSE Most candidate gene studies on the neurobiology of voluntary exercise behavior have focused on the dopaminergic signaling pathway and its role in the mesolimbic reward system. We hypothesized that dopaminergic candidate genes may influence exercise behavior through additional effects on executive functioning and that these effects are only detected when the types of exercise activity ar...