Complementary Features of Attention Bias Modification Therapy and Cognitive-Behavioral Therapy in Pediatric Anxiety Disorders.

OBJECTIVE: In the treatment of anxiety disorders, attention bias modification therapy (ABMT) and cognitive-behavioral therapy (CBT) may have complementary effects by targeting different aspects of perturbed threat responses and behaviors. ABMT may target rapid, implicit threat reactions, whereas CBT may target slowly deployed threat responses. The authors used amygdala-based connectivity during a threat-attention task and a randomized controlled trial design to evaluate potential complementary features of these treatments in pediatric anxiety disorders. METHOD: Prior to treatment, youths (8-17 years old) with anxiety disorders (N=54), as well as healthy comparison youths (N=51), performed a threat-attention task during functional MRI acquisition. Task-related amygdala-based functional connectivity was assessed. Patients with and without imaging data (N=85) were then randomly assigned to receive CBT paired with either active or placebo ABMT. Clinical response was evaluated, and pretreatment amygdala-based connectivity profiles were compared among patients with varying levels of clinical response. RESULTS: Compared with the CBT plus placebo ABMT group, the CBT plus active ABMT group exhibited less severe anxiety after treatment. The patient and healthy comparison groups differed in amygdala-insula connectivity during the threat-attention task. Patients whose connectivity profiles were most different from those of the healthy comparison group exhibited the poorest response to treatment, particularly those who received CBT plus placebo ABMT. CONCLUSIONS: The study provides evidence of enhanced clinical effects for patients receiving active ABMT. Moreover, ABMT appears to be most effective for patients with abnormal amygdala-insula connectivity. ABMT may target specific threat processes associated with dysfunctional amygdala-insula connectivity that are not targeted by CBT alone. This may explain the observation of enhanced clinical response to CBT plus active ABMT.

Age-related differences in the neural correlates of trial-to-trial variations of reaction time.

Intra-subject variation in reaction time (ISVRT) is a developmentally-important phenomenon that decreases from childhood through young adulthood in parallel with the development of executive functions and networks. Prior work has shown a significant association between trial-by-trial variations in reaction time (RT) and trial-by-trial variations in brain activity as measured by the blood-oxygenated level-dependent (BOLD) response in functional magnetic resonance imaging (fMRI) studies. It remains unclear, however, whether such "RT-BOLD" relationships vary with age. Here, we determined whether such trial-by-trial relationships vary with age in a cross-sectional design. We observed an association between age and RT-BOLD relationships in 11 clusters located in visual/occipital regions, frontal and parietal association cortex, precentral/postcentral gyrus, and thalamus. Some of these relationships were negative, reflecting increased BOLD associated with decreased RT, manifesting around the time of stimulus presentation and positive several seconds later. Critically for present purposes, all RT-BOLD relationships increased with age. Thus, RT-BOLD relationships may reflect robust, measurable changes in the brain-behavior relationship across development.

Neural circuitry engaged during unsuccessful motor inhibition in pediatric bipolar disorder.

OBJECTIVE: Deficits in motor inhibition may contribute to impulsivity and irritability in children with bipolar disorder. Studies of the neural circuitry engaged during failed motor inhibition in pediatric bipolar disorder may increase our understanding of the pathophysiology of the illness. The authors tested the hypothesis that children with bipolar disorder and comparison subjects would differ in ventral prefrontal cortex, striatal, and anterior cingulate activation during unsuccessful motor inhibition. They also compared activation in medicated versus unmedicated children with bipolar disorder and in children with bipolar disorder and attention deficit hyperactivity disorder (ADHD) versus those with bipolar disorder without ADHD. METHOD: The authors conducted an event-related functional magnetic resonance imaging study comparing neural activation in children with bipolar disorder and healthy comparison subjects while they performed a motor inhibition task. The study group included 26 children with bipolar disorder (13 unmedicated and 15 with ADHD) and 17 comparison subjects matched by age, gender, and IQ. RESULTS: On failed inhibitory trials, comparison subjects showed greater bilateral striatal and right ventral prefrontal cortex activation than did patients. These deficits were present in unmedicated patients, but the role of ADHD in mediating them was unclear. CONCLUSIONS: In relation to comparison subjects, children with bipolar disorder may have deficits in their ability to engage striatal structures and the right ventral prefrontal cortex during unsuccessful inhibition. Further research should ascertain the contribution of ADHD to these deficits and the role that such deficits may play in the emotional and behavioral dysregulation characteristic of bipolar disorder.

Using affect-modulated startle to study phenotypes of pediatric bipolar disorder.

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.