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Nagata, J.

Publications and source records attributed to Nagata, J..

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Aberrant Functional Connectivity between Reward and Inhibitory Control Networks in Pre-Adolescent Binge Eating Disorder

BackgroundBehavioral features of binge eating disorder (BED) suggest abnormalities in reward and inhibitory control. Studies of adult populations suggest functional abnormalities in reward and inhibitory control networks. Despite behavioral markers often developing in children, the neurobiology of pediatric BED remains unstudied. Methods58 pre-adolescent children (aged 9-10-years) with BED and 66 age, BMI and developmentally-matched control children were extracted from the 3.0 baseline (Year 0) release of the Adolescent Brain Cognitive Development (ABCD) Study. We investigated group differences in resting-state functional MRI (rs-fMRI) functional connectivity (FC) within and between reward and inhibitory control networks. A seed-based approach was employed to assess nodes in the reward (orbitofrontal cortex, nucleus accumbens, amygdala) and inhibitory control (dorsolateral prefrontal cortex, anterior cingulate cortex) networks via hypothesis-driven seed-to- seed analyses, and secondary seed-to-voxel analyses. ResultsOur findings revealed reduced FC between the dlPFC and amygdala, and between the anterior cingulate cortex and orbitofrontal cortex in pre-adolescent children with BED, relative to age, gender, BMI and developmentally matched controls. These findings indicating aberrant connectivity between nodes of inhibitory control and reward networks were corroborated by the whole-brain FC analyses. ConclusionsEarly-onset BED may be characterized by diffuse abnormalities in the functional synergy between reward and cognitive control networks, without perturbations within reward and inhibitory control networks, respectively. The decreased capacity to regulate a reward-driven pursuit of hedonic foods, which is characteristic of BED, may in part, rest on this dysconnectivity between reward and inhibitory control networks.

neuroscience

Examining the genetic influences of migratory status on island colonisation by naturally and recently established populations of a bird species

AimFounder effects and recurrent immigration are two major factors that potentially contribute to genetic differentiation and population persistence in the early-stage of remote island colonization. However, their relative importance remains controversial. By conducting population genetics analyses of multiple remote island populations of the bull-headed shrike established naturally within several decades, we examined the relative contributions of founder effects and recurrent immigration on these island populations. LocationJapan TaxonLanius bucephalus MethodsWe used 15 microsatellite loci to analyze the population genetics of four newly established island populations and five Japanese mainland populations. Allelic richness, heterozygosity, genetic differentiation, and the strength of the genetic bottleneck were compared among the islands. Two analyses, STRUCTURE and the DAPC, were conducted to assess the relative influence of founder effects and recurrent immigration on genetic differentiation. Temporal samples collected over eight years on Minami-Daito Island were used to detect any change in genetic structure due to recurrent immigration. ResultsThe founder effect strongly influenced genetic differentiation on the most remote oceanic island, Chichi-jima Island. However, this population became extinct 20 years after colonization, possibly owing to a lack of recurrent immigration. The founder effect moderately influenced a land-bridge island, Kikai-jima Island, indicating the presence of a relatively large founder population without recurrent immigration. Surprisingly, another distant oceanic island, Minami-Daito Island, was likely subject to multiple recurrent immigration events from the mainland, which obscured any genetic differentiation previously established by the founder effect. Main conclusionUnderlying the island-specific population dynamics of colonization, founder effects contributed to the genetic differentiation among the three studied island populations. Importantly, however, recurrent immigration strongly affected the population persistence and subsequent evolutionary processes of remote island populations, potentially overwhelming the founder effect. We argue the importance of recurrent immigration in highly remote island colonization, which has been previously overlooked.

ecology