1,720,964 research outputs found
A prospective study of the impact of severe childhood deprivation on brain white matter in adult adoptees: Widespread localized reductions in volume but unaffected microstructural organization
No full textBackground: Early childhood neglect can impact brain development across the lifespan. Using voxel-based approaches we recently reported that severe and time-limited institutional deprivation in early childhood was linked to substantial reductions in total brain volume in adulthood, more than twenty years later. Here we extend this analysis to explore deprivation-related regional white matter volume and microstructural organization using diffusion-based techniques. Methods: A combination of tensor-based morphometry analysis and tractography was conducted on diffusion weighted imaging data from 59 young adults who spent between 3 and 41 months in the severely depriving Romanian institutions of the 1980’s before being adopted into UK families, and 20 non-deprived age-matched UK controls.Results: Independent of total volume, institutional deprivation was associated with smaller volumes in localized regions across a range of white matter tracts including (1) long-ranging association fibers such as bilateral inferior longitudinal fasciculus, bilateral inferior fronto-occipital fasciculus, left superior longitudinal fasciculi, and left arcuate fasciculus; (2) tracts of the limbic circuitry including fornix and cingulum; and (3) projection fibers with the corticospinal tract particularly affected. Tractographic analysis found no evidence of altered microstructural organization of any tract in terms of hindrance modulated orientational anisotropy (HMOA), fractional anisotropy (FA) or mean diffusivity (MD). Discussion: We provide further evidence for the effects of early neglect on brain development and their persistence in adulthood despite many years of environmental enrichment associated with successful adoption. Localized white matter effects appear limited to volumetric changes with microstructural organization unaffected.<br/
The impact of childhood deprivation on adult neuropsychological functioning is associated with ADHD symptom persistence
No full textBackground: Institutional deprivation in early childhood is associated with neuropsychological deficits in adolescence. Using 20-year follow-up data from a unique natural experiment – the large-scale adoption of children exposed to extreme deprivation in Romanian institutions in the 1980s –we examined, for the first time, whether such deficits are still present in adulthood and whether they are associated with deprivation- related symptoms of attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). Methods: Adult neuropsychological functioning was assessed across five domains (inhibitory control, emotion recognition, decision-making, prospective memory and IQ) in 70 previously-institutionalized adoptees (mean age= 25.3, 50% female) and 22 non-deprived UK adoptees (comparison group, mean age= 24.6, 41% female). ADHD and ASD symptoms were assessed using parent-completed questionnaires. Results: Early institutionalization was associated with impaired performance on all tasks in adulthood. Prospective memory deficits persisted after controlling for IQ. ADHD and ASD symptoms were positively correlated. After controlling for ASD symptoms, ADHD symptoms remained associated with deficits in IQ, prospective memory, proactive inhibition, decision-making quality and emotion recognition. ASD symptoms were not independently associated with neuropsychological deficits when accounting for their overlap with ADHD symptoms. Multiple regression analysis revealed that the link between childhood deprivation and adult ADHD symptoms was statistically explained by deprivation-related differences in adult IQ and prospective memory. Conclusions: These results represent some of the most compelling evidence to date of the enduring power of early, time-limited childhood adversity to impair long-term neuropsychological functioning across the lifespan – effects that are linked specifically to deprivation-related adult ADHD symptoms
Early childhood deprivation is associated with alterations in adult brain structure despite subsequent environmental enrichment
Full text linkEarly childhood deprivation is associated with higher rates of neurodevelopmental and mental disorders in adulthood. The impact of childhood deprivation on the adult brain and the extent to which structural changes underpin these effects are currently unknown. To investigate these questions, we utilized MRI data collected from young adults who were exposed to severe deprivation in early childhood in the Romanian orphanages of the Ceauşescu era and then, subsequently adopted by UK families; 67 Romanian adoptees (with between 3 and 41 mo of deprivation) were compared with 21 nondeprived UK adoptees. Romanian adoptees had substantially smaller total brain volumes (TBVs) than nondeprived adoptees (8.6% reduction), and TBV was strongly negatively associated with deprivation duration. This effect persisted after covarying for potential environmental and genetic confounds. In whole-brain analyses, deprived adoptees showed lower right inferior frontal surface area and volume but greater right inferior temporal lobe thickness, surface area, and volume than the nondeprived adoptees. Right medial prefrontal volume and surface area were positively associated with deprivation duration. No deprivation-related effects were observed in limbic regions. Global reductions in TBV statistically mediated the observed relationship between institutionalization and both lower intelligence quotient (IQ) and higher levels of attention deficit/hyperactivity disorder symptoms. The deprivation-related increase in right inferior temporal volume seemed to be compensatory, as it was associated with lower levels of attention deficit/hyperactivity disorder symptoms. We provide compelling evidence that time-limited severe deprivation in the first years of life is related to alterations in adult brain structure, despite extended enrichment in adoptive homes in the intervening years.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Tracking emotions in the brain - Revisiting the Empathic Accuracy Task
Full text linkMany empathy tasks lack ecological validity due to their use of simplistic stimuli and static analytical approaches. Empathic accuracy tasks overcome these limitations by using autobiographical emotional video clips. Usually, a single measure of empathic accuracy is computed by correlating the participants' continuous ratings of the narrator's emotional state with the narrator's own ratings.In this study, we validated a modified empathic accuracy task. A valence-independent rating of the narrator's emotional intensity was added to provide comparability between videos portraying different primary emotions and to explore changes in neural activity related to variations in emotional intensity over time. We also added a new neutral control condition to investigate general emotional processing. In the scanner, 34 healthy participants watched 6 video clips of people talking about an autobiographical event (2 sad, 2 happy and 2 neutral clips) while continuously rating the narrator's emotional intensity.Fluctuation in perceived emotional intensity correlated with activity in brain regions previously implicated in cognitive empathy (bilateral superior temporal sulcus, temporoparietal junction, and temporal pole) and affective empathy (right anterior insula and inferior frontal gyrus). When emotional video clips were compared to neutral video clips, we observed higher activity in similar brain regions. Empathic accuracy, on the other hand, was only positively related to activation in regions that have been implicated in cognitive empathy.Our modified empathic accuracy task provides a new method for studying the underlying components and dynamic processes involved in empathy. While the task elicited both cognitive and affective empathy, successful tracking of others' emotions relied predominantly on the cognitive components of empathy. The fMRI data analysis techniques developed here may prove valuable in characterising the neural basis of empathic difficulties observed across a range of psychiatric conditions
The impact of early institutional deprivation on brain structure and structural covariance in young adulthood
Full text linkDispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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