We tested whether dynamic interaction between limbic regions supports a control systems model of excitatory and inhibitory components of a negative feedback loop, and whether dysregulation of those dynamics might correlate with trait differences in anxiety and their cardiac characteristics among healthy adults. Experimental Design: Sixty-five subjects received fMRI scans while passively viewing angry, fearful, happy, and neutral facial stimuli. Subjects also completed a trait anxiety inventory, and were monitored using ambulatory wake ECG. The ECG data were analyzed for heart rate variability, a measure of autonomic regulation. The fMRI data were analyzed with respect to six limbic regions (bilateral amygdala, bilateral hippocampus, Broadmann Areas 9, 45) using limbic time-series cross-correlations, maximum BOLD amplitude, and BOLD amplitude at each point in the time-series. Principal Observations: Diminished coupling between limbic time-series in response to the neutral, fearful, and happy faces was associated with greater trait anxiety, greater sympathetic activation, and lowered heart rate variability. Individuals with greater levels of trait anxiety showed delayed activation of Brodmann Area 45 in response to the fearful and happy faces, and lowered Brodmann Area 45 activation with prolonged left amygdala activation in response to the neutral faces. Conclusions: The dynamics support limbic regulation as a control system, in which dysregulation, as assessed by diminished coupling between limbic time-series, is associated with increased trait anxiety and excitatory autonomic outputs. Trait-anxious individuals showed delayed inhibitory activation in response to overt-affect stimuli and diminished inhibitory activation with delayed extinction of excitatory activation in response to ambiguous-affect stimuli. Hum Brain Mapp 30:47-58,2009. (c) 2007 Wiley-Liss, Inc.

Background. The presence of the adhesion molecules intercellular adhesion molecule-1 (ICAM-1) and soluble vascular cell adhesion molecule-1 (VCAM-1) is associated with elevated risk of cardiovascular disease. Subjects with human immunodeficiency virus (HIV) disease have multiple risk factors for cardiovascular disease, including elevated serum lipid levels, insulin resistance, and elevated levels of ICAM-1 and VCAM-1. This study assessed the variables associated with elevated adhesion molecule levels in this patient population.Methods. Serum levels of ICAM-1 and VCAM-1 were assessed in 31 subjects without HIV disease and 52 subjects with HIV disease. Pearson correlation indicated a significant relationship between ICAM concentration and other variables, including CD4(+) cell count, HIV viral burden, insulin sensitivity, and serum lipid level. Multiple regression modeling was used to determine the strengths of association among the variables.Results. Subjects with HIV disease had elevated levels of ICAM-1 and VCAM-1. Pearson correlation analysis revealed significant associations between ICAM-1 and VCAM-1 level and insulin sensitivity, plasma lipid level, and presence of type 2 soluble receptor for tumor necrosis factor-alpha (sTNFR2). With multiple regression modeling to control for interdependence, only sTNFR2, a marker of inflammation, was an independent predictor of ICAM-1 and VCAM-1 levels.Conclusions. The study suggests that many of the variables associated with ICAM-1 and VCAM-1 levels can be related to their impact on inflammation.