26 research outputs found
Enhancing studies of the connectome in autism using the autism brain imaging data exchange II
The second iteration of the Autism Brain Imaging Data Exchange (ABIDE II) aims to enhance the scope of brain connectomics research in Autism Spectrum Disorder (ASD). Consistent with the initial ABIDE effort (ABIDE I), that released 1112 datasets in 2012, this new multisite open-data resource is an aggregate of resting state functional magnetic resonance imaging (MRI) and corresponding structural MRI and phenotypic datasets. ABIDE II includes datasets from an additional 487 individuals with ASD and 557 controls previously collected across 16 international institutions. The combination of ABIDE I and ABIDE II provides investigators with 2156 unique cross-sectional datasets allowing selection of samples for discovery and/or replication. This sample size can also facilitate the identification of neurobiological subgroups, as well as preliminary examinations of sex differences in ASD. Additionally, ABIDE II includes a range of psychiatric variables to inform our understanding of the neural correlates of co-occurring psychopathology; 284 diffusion imaging datasets are also included. It is anticipated that these enhancements will contribute to unraveling key sources of ASD heterogeneity
Analysis of shared heritability in common disorders of the brain
ience, this issue p. eaap8757 Structured Abstract INTRODUCTION Brain disorders may exhibit shared symptoms and substantial epidemiological comorbidity, inciting debate about their etiologic overlap. However, detailed study of phenotypes with different ages of onset, severity, and presentation poses a considerable challenge. Recently developed heritability methods allow us to accurately measure correlation of genome-wide common variant risk between two phenotypes from pools of different individuals and assess how connected they, or at least their genetic risks, are on the genomic level. We used genome-wide association data for 265,218 patients and 784,643 control participants, as well as 17 phenotypes from a total of 1,191,588 individuals, to quantify the degree of overlap for genetic risk factors of 25 common brain disorders. RATIONALE Over the past century, the classification of brain disorders has evolved to reflect the medical and scientific communities' assessments of the presumed root causes of clinical phenomena such as behavioral change, loss of motor function, or alterations of consciousness. Directly observable phenomena (such as the presence of emboli, protein tangles, or unusual electrical activity patterns) generally define and separate neurological disorders from psychiatric disorders. Understanding the genetic underpinnings and categorical distinctions for brain disorders and related phenotypes may inform the search for their biological mechanisms. RESULTS Common variant risk for psychiatric disorders was shown to correlate significantly, especially among attention deficit hyperactivity disorder (ADHD), bipolar disorder, major depressive disorder (MDD), and schizophrenia. By contrast, neurological disorders appear more distinct from one another and from the psychiatric disorders, except for migraine, which was significantly correlated to ADHD, MDD, and Tourette syndrome. We demonstrate that, in the general population, the personality trait neuroticism is significantly correlated with almost every psychiatric disorder and migraine. We also identify significant genetic sharing between disorders and early life cognitive measures (e.g., years of education and college attainment) in the general population, demonstrating positive correlation with several psychiatric disorders (e.g., anorexia nervosa and bipolar disorder) and negative correlation with several neurological phenotypes (e.g., Alzheimer's disease and ischemic stroke), even though the latter are considered to result from specific processes that occur later in life. Extensive simulations were also performed to inform how statistical power, diagnostic misclassification, and phenotypic heterogeneity influence genetic correlations. CONCLUSION The high degree of genetic correlation among many of the psychiatric disorders adds further evidence that their current clinical boundaries do not reflect distinct underlying pathogenic processes, at least on the genetic level. This suggests a deeply interconnected nature for psychiatric disorders, in contrast to neurological disorders, and underscores the need to refine psychiatric diagnostics. Genetically informed analyses may provide important "scaffolding" to support such restructuring of psychiatric nosology, which likely requires incorporating many levels of information. By contrast, we find limited evidence for widespread common genetic risk sharing among neurological disorders or across neurological and psychiatric disorders. We show that both psychiatric and neurological disorders have robust correlations with cognitive and personality measures. Further study is needed to evaluate whether overlapping genetic contributions to psychiatric pathology may influence treatment choices. Ultimately, such developments may pave the way toward reduced heterogeneity and improved diagnosis and treatment of psychiatric disorders
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Use of standardized methods to improve extinction‐risk classification
Standardized classification methods based on quantifiable risk metrics are critical for evaluating extinction threats because they increase objectivity, consistency, and transparency of listing decisions. Yet, in the United States, neither federal nor state agencies use standardized methods for listing species for legal protection, which could put listing decisions at odds with the magnitude of the risk. We used a recently developed set of quantitative risk metrics for California herpetofauna as a case study to highlight discrepancies in listing decisions made without standardized methods. We also combined such quantitative metrics with classification tree analysis to attempt to increase the transparency of previous listing decisions by identifying the criteria that had inherently been given the most weight. Federally listed herpetofauna in California scored significantly higher on the risk‐metric spectrum than those not federally listed, whereas state‐listed species did not score any higher than species that were not state listed. Based on classification trees, state endemism was the most important predictor of listing status at the state level and distribution trend (decline in a species’ range size) and population trend (decline in a species’ abundance at localized sites) were the most important predictors at the federal level. Our results emphasize the need for governing bodies to adopt standardized methods for assessing conservation risk that are based on quantitative criteria. Such methods allow decision makers to identify criteria inherently given the most weight in determining listing status, thus increasing the transparency of previous listing decisions, and produce an unbiased comparison of conservation threat across all species to promote consistency, efficiency, and effectiveness of the listing process.
Article impact statement: Using standardized, quantitative methods to assess extinction risk can improve listing decisions by increasing consistency and transparency
Uso de Métodos Estandarizados para Mejorar la Clasificación del Riesgo de Extinción
Resumen
Los métodos estandarizados de clasificación basados en medidas cuantificables del riesgo de extinción son sumamente importantes para evaluar las amenazas de extinción ya que incrementan la objetividad, consistencia y transparencia de las decisiones de listado. Aún así, en los Estados Unidos, ni las agencias federales ni las estatales usan métodos estandarizados para enlistar a las especies para su protección legal, lo que podría poner en discrepancia a las decisiones de listado con la magnitud del riesgo. Usamos un conjunto de medidas cuantitativas del riesgo, desarrollado recientemente para la herpetofauna de California, como un estudio de caso que nos permitiera resaltar las discrepancias en las decisiones de listado hechas sin métodos estandarizados. También combinamos dichas medidas cuantitativas con un análisis de árbol de clasificación para intentar incrementar la transparencia de las decisiones de listado previas al identificar los criterios a los cuales se les había otorgado mayor peso inherentemente. La herpetofauna de California que se encontraba enlistada a nivel federal tuvo un puntaje significativamente más alto en el espectro de la medida del riesgo que aquellas especies que no estaban enlistadas, mientras que las especies enlistadas a nivel estatal no tuvieron un puntaje más alto que aquellas especies que no estaban enlistadas a nivel estatal. Con base en los árboles de clasificación, el endemismo estatal fue el indicador más importante del estado de listado a nivel estatal y tanto la tendencia de distribución (declinación del tamaño de la extensión de una especie) y como la tendencia poblacional (declinación de la abundancia de una especie en sitios localizados) fueron los indicadores más importantes a nivel federal. Nuestros resultados enfatizan la necesidad que tienen los cuerpos de gobierno de adoptar los métodos estandarizados que están basados en criterios cuantitativos para la evaluación del riesgo de conservación. Dichos métodos permiten que quienes toman las decisiones identifiquen los criterios a los cuales se les otorga inherentemente el mayor peso al determinar el estado de listado, lo que incrementa la transparencia de las decisiones previas de listado, y produce una comparación sin sesgos de la amenaza de conservación en todas las especies para promover la regularidad, eficiencia y efectividad de los procesos de listado.
摘要
基于定量风险指标的标准化分类方法可以提高濒危物种名录确定的客观性、一致性和透明度, 因而对评估物种的灭绝风险十分重要。然而, 在美国, 无论是联邦机构还是州立机构, 都没有使用标准化方法来确定法律保护的濒危物种, 这可能会导致濒危物种名录决策与物种面临的灭绝风险程度不相一致。我们以最近开发的一套美国加州爬行动物区系定量风险指标为例, 展示了标准化方法的使用与否在濒危物种名录确定中产生的差异。我们还将这些定量指标与分类树分析相结合, 试图通过找出之前的确定方法中占权重最大的指标来增加决策的透明度。被联邦政府列入名录的加州爬行动物的风险指标谱得分明显高于那些没有列入名录的物种, 而州政府列入名录的物种得分却并不比没有列入的物种高。分类树结果还显示, 州级濒危等级最重要的预测因子为州级特有性, 而在联邦一级最重要的预测因子则是分布趋势 (物种分布范围的缩小) 和种群趋势 (局部地区物种丰度的下降) 。我们的研究结果突出表明管理机构应采用基于定量指标的标准化方法来评估保护风险。这些方法可以帮助决策者找到濒危等级确定中最重要的指标, 从而增加已有确定方法的透明度, 还可以通过公正地比较所有物种面临的保护威胁, 以提升濒危物种名录确定过程中的一致性、效率和效果。【翻译: 胡怡思; 审校: 聂永刚