21 research outputs found

    Microstructural dynamics of motor learning and sleep-dependent consolidation: A diffusion imaging study

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    Memory consolidation can benefit from post-learning sleep, eventually leading to long-term microstructural brain modifications to accommodate new memory representations. Non-invasive diffusion-weighted magnetic resonance imaging (DWI) allows the observation of (micro)structural brain remodeling after time-limited motor learning. Here, we combine conventional diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) that allows modeling dendritic and axonal complexity in gray matter to investigate with improved specificity the microstructural brain mechanisms underlying time- and sleep-dependent motor memory consolidation dynamics. Sixty-one young healthy adults underwent four DWI sessions, two sequential motor trainings, and a night of total sleep deprivation or regular sleep distributed over five days. We observed rapid-motor-learning-related remodeling in occipitoparietal, temporal, and motor-related subcortical regions, reflecting temporary dynamics in learning-related neuronal brain plasticity processes. Sleep-related consolidation seems not to exert a detectable impact on diffusion parameters, at least on the timescale of a few days

    Is emotional dysregulation a component of attention-deficit/hyperactivity disorder (ADHD) ?

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    International audienceINTRODUCTION: Attention-deficit/hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder in children and adolescents. It is characterized by age-inappropriate inattention/impulsiveness and/or hyperactivity symptoms. ADHD shows a high comorbidity with oppositional defiant disorder (ODD), a disorder that features symptoms of emotional lability. Due to this comorbidity, emotional lability was long considered a secondary consequence of ADHD, which could arise under the influence of environmental factors such as inefficient parenting practices, as part of an ODD diagnosis. In this model of heterotypic continuity, emotional lability was considered not to play any causal role regarding ADHD symptomatology. LITERATURE FINDINGS: As opposed to this view, it is now well established that a large number of children with ADHD and without any comorbid disorder exhibit symptoms of emotional lability. Furthermore, recent studies have found that negative emotionality accounts for significant unique variance in ADHD symptom severity, along with motor-perceptual and executive function deficits. Barkley proposed that ADHD is characterized by deficits of executive functions, and that a deficiency in the executive control of emotions is a necessary component of ADHD. According to this theory, the extent to which an individual with ADHD displays a deficiency in behavioral inhibition is the extent to which he or she will automatically display an equivalent degree of deficiency in emotional inhibition. However, not all children with ADHD exhibit symptoms of emotional lability, and studies have found that the association between emotional lability and ADHD was not mediated by executive function or motivational deficits. Task-based and resting state neuroimaging studies have disclosed an altered effective connectivity between regions dedicated to emotional regulation in children with ADHD when compared to typically developing children, notably between the amygdala, the prefrontal cortex, the hippocampus and the ventral striatum. Morphological alterations of the amygdala have also been reported in previous structural studies in children with ADHD. DISCUSSION: Emotional lability can result from different neurobiological mechanisms. In particular, bottom-up and top-down processes can be opposed. Bottom-up related emotional dysregulation involves an increased emotional reactivity, and is thought to be linked to the automatic evaluative activity of the amygdala. Top-down mechanisms are associated with the regulation of such activity, and rely on a prefrontal network including the lateral prefrontal cortex, the anterior cingulate cortex and the orbitofrontal cortex. Since various neuropsychological impairments and alterations in multiple brain networks have been implicated in the etiology of ADHD, contemporary models emphasize its neuropsychological heterogeneity. It is therefore likely that some but not all children with ADHD will exhibit neurobiological alterations in circuits dedicated to emotional regulation, possibly at different levels. Future research will have to identify the different causal pathways and to decide whether emotional lability represents a criterion to subtype ADHD diagnoses. CONCLUSION: Emotional dysregulation is now known to play a causal role regarding ADHD symptomatology. Along with executive functioning, reaction time variability and potentially delay aversion, emotional dysregulation should therefore be included in future theoretical models of ADHD, as well as in clinical practice when identifying the major impairments in this diagnostic group and when deciding therapeutic strategies

    Correction of Susceptibility Distortion in EPI: A Semi-supervised Approach with Deep Learning

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    Echo planar imaging (EPI) is the most common approach for acquiring diffusion and functional MRI data due to its high temporal resolution. However, this comes at the cost of higher sensitivity to susceptibility-induced B0 field inhomogeneities around air/tissue interfaces. This leads to severe geometric distortions along the phase encoding direction (PED). To correct this distortion, the standard approach involves an analogous acquisition using an opposite PED leading to images with inverted distortions and then non-linear image registration, with a transformation model constrained along the PED, to estimate the voxel-wise shift that undistorts the image pair and generates a distortion-free image. With conventional image registration approaches, this type of processing is computationally intensive. Recent advances in unsupervised deep learning-based approaches to image registration have been proposed to drastically reduce the computational cost of this task. However, they rely on maximizing an intensity-based similarity measure, known to be suboptimal surrogate measures of image alignment. To address this limitation, we propose a semi-supervised deep learning algorithm that directly leverages ground truth spatial transformations during training. Simulated and real data experiments demonstrate improvement to distortion field recovery compared to the unsupervised approach, improvement image similarity compared to supervised approach and precision similar to TOPUP but with much faster processing

    Promoting psychological well-being in preschool children: study protocol for a randomized controlled trial of a mindfulness- and yoga-based socio-emotional learning intervention

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    Abstract Background Mental health issues in youths have cascading negative effects on school outcomes, professional life, and physical health. Psychological well-being (P-WB) is an important protective factor against mental illness. Preliminary research suggests that mindfulness- and yoga-based socio-emotional learning (SEL) interventions can each have a positive impact on preschoolers P-WB. The objective of this trial is to rigorously evaluate the effect of a 24-week combined mindfulness- and yoga- based SEL intervention in preschool children from a French socio-economically disadvantaged area. Methods The P-WB promotion intervention is compared to a wait-list control condition in a cluster randomized controlled trial (RCT). Sixty-four pre-Kindergarten classrooms are randomized to the intervention or control group. Primary outcomes measure self-management capacity and core P-WB components: connection, insight, engagement, and positive relationship. Secondary outcomes include measures of mental health, executive functioning, and school performance. Primary and secondary outcomes are assessed through teacher questionnaires, standardized observations of children in school context, and experimental tasks and by collecting results of the national evaluation at first grade. All children-level outcomes are evaluated at pre-intervention, at the end of the intervention, and 1 year later (follow-up analysis), to the exception of school performance which is evaluated at follow-up only. Intention-to-treat analyses, accounting for clustering within classes, will adopt a random effects linear regression model to examine outcomes for the intervention versus control children. Discussion This is the first trial to rigorously evaluate a combined mindfulness- and yoga-based P-WB promotion intervention, and the first RCT evaluating a SEL curriculum in French schools. Results may have key implications for P-WB promotion in preschool children. Trial registration https://www.drks.de/ DRKS00028623. Retrospectively registered on 30 May 202
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