OBJECTIVES: Affective neuroscience research that investigates core symptoms of pediatric bipolar disorder (PBD) may be effective in differentiating PBD phenotypes. The current study used affect-modulated startle to examine potential differences in reactivity to emotional stimuli (reward and punishment) in narrow and broad phenotype PBD and controls. METHODS: Thirty children meeting DSM-IV bipolar disorder criteria (i.e. narrow phenotype PBD with defined manic episodes with elevated/expansive mood), 19 children meeting criteria for severe mood dysregulation (i.e. broad phenotype with chronic irritability, hyper-reactivity, and hyperarousal), and 19 controls completed a lottery startle paradigm involving reward (money) and punishment (loud noise). Startle probes were presented during anticipation of the emotional stimulus, immediately following the presentation of the stimulus, or during return to baseline following the stimulus. RESULTS: By self-report, patients and controls found the putative punishment to be preferable to the neutral condition. In the reward condition, patient samples reported greater arousal than did controls, but no between-group differences were found on the magnitude of startle response during the reward, punishment, or neutral conditions. CONCLUSIONS: The failure to find differences in affect-modulated startle between control children and those with narrow or broad PBD phenotypes speaks to the methodological challenges associated with studying reward mechanisms in PBD. Alternative paradigms that focus on different aspects of reward mechanisms are discussed.
We present a novel weighted Fourier series (WFS) representation for cortical surfaces. The WFS representation is a data smoothing technique that provides the explicit smooth functional estimation of unknown cortical boundary as a linear combination of basis functions. The basic properties of the representation are investigated in connection with a self-adjoint partial differential equation and the traditional spherical harmonic (SPHARM) representation. To reduce steep computational requirements, a new iterative residual fitting (IRF) algorithm is developed. Its computational and numerical implementation issues are discussed in detail. The computer codes are also available at http://www.stat.wisc.edu/-mchung/softwares/weighted.SPHARM/weighted-SPHARM.html. As an illustration, the WFS is applied i n quantifying the amount ofgray matter in a group of high functioning autistic subjects. Within the WFS framework, cortical thickness and gray matter density are computed and compared.
It has been widely assumed that emotional avoidance during bereavement leads to either prolonged grief, delayed grief, or delayed somatic symptoms. To test this view, as well as a contrasting adaptive hypothesis, emotional avoidance was measured 6 months after a conjugal loss as negative verbal-autonomic response dissociation (low self-rated negative emotion coupled with heightened cardiovascular activity) and compared with grief measured at 6 and 14 months. The negative dissociation score evidenced reliability and validity but did not evidence the assumed link to severe grief. Rather, consistent with the adaptive hypothesis, negative dissociation at 6 months was associated with minimal grief symptoms across 14 months. Negative dissociation scores were also linked to initially high levels of somatic symptoms, which dropped to a low level by 14 months. Possible explanations for the initial cost and long-term adaptive quality of emotional avoidance during bereavement, as well as implications and limitations of the findings, are discussed.
BACKGROUND: Recent studies have highlighted the role of right-sided anterior temporal and prefrontal activation during anxiety, yet no study has been performed with social phobics that assesses regional brain and autonomic function. This study compared electroencephalograms (EEGs) and autonomic activity in social phobics and controls while they anticipated making a public speech. METHODS: Electroencephalograms from 14 scalp locations, heart rate, and blood pressure were recorded while 18 DSM-IV social phobics and 10 controls anticipated making a public speech, as well as immediately after the speech was made. Self-reports of anxiety and affect were also obtained. RESULTS: Phobics showed a significantly greater increase in anxiety and negative affect during the anticipation condition compared with controls. Heart rate was elevated in the phobics relative to the controls in most conditions. Phobics showed a marked increase in right-sided activation in the anterior temporal and lateral prefrontal scalp regions. These heart rate and EEG changes together accounted for > 48% of the variance in the increase in negative affect during the anticipation phase. CONCLUSIONS: These findings support the hypothesis of right-sided anterior cortical activation during anxiety and indicate that the combination of EEG and heart rate changes during anticipation account for substantial variance in reported negative affect.