Sustained attention and executive functioning performance in attention-deficit/hyperactivity disorder

Contains fulltext : 48157.pdf (publisher's version ) (Closed access)The aim of this study was to further refine the cognitive phenotype of attention-deficit/hyperactivity disorder (ADHD), with respect to the ability to sustain attention and executive functioning. Participants were 34 boys with ADHD (combined type) and 28 normal controls. The groups were closely matched for age and IQ. All participants were 12 years of age. Both groups performed a computerized sustained attention task and a response interference task. Measures related to speed, accuracy, and time on task were collected. We found that children with ADHD performed slower, less accurately, more impulsively, and with less stability than controls. Both groups produced more errors with increasing time on task, reflecting reduced vigilance. Importantly, no interaction with time on task was found. The overall pattern of results suggests that measures related to accuracy are more informative than measures related to speed of responding in refining the cognitive phenotype of ADHD

ac Josephson effect in the resonant tunneling through mesoscopic superconducting junctions

We investigate ac Josephson effect in the resonant tunneling through mesoscopic superconducting junctions. In the presence of microwave irradiation, we show that the trajectory of multiple Andreev reflections can be closed by emitting or absorbing photons. Consequently, photon-assisted Andreev states are formed and play the role of carrying supercurrent. On the Shapiro steps, dc component appears when the resonant level is near a series of positions with spacing of half of the microwave frequency. Analytical result is derived in the limit of infinite superconducting gap, based on which new features of ac Josephson effect are revealed.Comment: 11 pages, 3 figure

Identification of an age-dependent biomarker signature in children and adolescents with autism spectrum disorders

Background: Autism spectrum disorders (ASDs) are neurodevelopmental conditions with symptoms manifesting before the age of 3, generally persisting throughout life and affecting social development and com

Psychosocial stress and brain function in adolescent psychopathology

Objective: To explore how conduct, hyperactivity/inattention, and emotional symptoms are associated with neural reactivity to social-emotional stimuli, and the extent to which psychosocial stress modulates these relationships. Method: Participants were community adolescents recruited as part of the European IMAGEN study. Bilateral amygdala regions of interest were used to assess the relationship between the three symptom domains with fMRI neural reactivity during passive viewing of dynamic angry and neutral facial expressions. Exploratory functional connectivity and whole-brain multiple regression approaches were used to analyze how the symptoms and psychosocial stress relate to other brain regions. Results: In response to the social-emotional stimuli, adolescents with high levels of conduct or hyperactivity/inattention symptoms showed hyperactivity of the amygdala, and several regions across the brain, when they experienced a greater number of stressful life events. This effect was not observed with emotional symptoms. A cluster in the mid-cingulate was found to be common to both conduct problems and hyperactivity symptoms. Exploratory functional connectivity analyses suggested amygdala-precuneus connectivity is associated with hyperactivity/inattention symptoms. Conclusions: The results link hyperactive amygdala responses, and regions critical for top-down emotional processing, with high levels of psychosocial stress in individuals with greater conduct and hyperactivity/inattention symptoms. This work highlights the importance of studying how psychosocial stress impacts functional brain responses to social-emotional stimuli, particularly in adolescents with externalizing symptoms

Virtual Ontogeny of Cortical Growth Preceding Mental Illness

Background: Morphology of the human cerebral cortex differs across psychiatric disorders, with neurobiology and developmental origins mostly undetermined. Deviations in the tangential growth of the cerebral cortex during pre/perinatal periods may be reflected in individual variations in cortical surface area later in life. Methods: Interregional profiles of group differences in surface area between cases and controls were generated using T1-weighted magnetic resonance imaging from 27,359 individuals including those with attention-deficit/hyperactivity disorder, autism spectrum disorder, bipolar disorder, major depressive disorder, schizophrenia, and high general psychopathology (through the Child Behavior Checklist). Similarity of interregional profiles of group differences in surface area and prenatal cell-specific gene expression was assessed. Results: Across the 11 cortical regions, group differences in cortical area for attention-deficit/hyperactivity disorder, schizophrenia, and Child Behavior Checklist were dominant in multimodal association cortices. The same interregional profiles were also associated with interregional profiles of (prenatal) gene expression specific to proliferative cells, namely radial glia and intermediate progenitor cells (greater expression, larger difference), as well as differentiated cells, namely excitatory neurons and endothelial and mural cells (greater expression, smaller difference). Finally, these cell types were implicated in known pre/perinatal risk factors for psychosis. Genes coexpressed with radial glia were enriched with genes implicated in congenital abnormalities, birth weight, hypoxia, and starvation. Genes coexpressed with endothelial and mural genes were enriched with genes associated with maternal hypertension and preterm birth. Conclusions: Our findings support a neurodevelopmental model of vulnerability to mental illness whereby prenatal risk factors acting through cell-specific processes lead to deviations from typical brain development during pregnancy