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Visual Processing Abnormalities in Anorexia Nervosa and Body Dysmorphic Disorder
Full text linkAnorexia Nervosa (AN) and Body Dysmorphic Disorder (BDD) are disorders of body image that share phenomenological and psychological patterns of flawed perception of appearance. Our working model of visual processing dysfunction in AN and BDD describes a primary deficit in configural/holistic visual processing. The consequence of this is a secondary, “inappropriate,” reliance on detailed processing of image features, which is abnormally deployed in situations in which healthy controls deploy configural processing. We hypothesize that this results in a diminished holistic template that is less able to aid in integration, producing a conscious perception dominated by details. We used EEG and fMRI to investigate possible biomarkers of aberrant early visual system activity, that may inform diagnoses, treatments, and therapies in the future.The aim of my thesis is to understand the neural dynamics underlying visual processing abnormalities in AN and BDD. I used neuroimaging techniques, specifically functional magnetic resonance imaging (fMRI) and electroencephalography (EEG), to address this research question. Several fMRI studies have shown abnormal brain activation patterns during global encoding of faces and objects for BDD (1–3) and AN (4; 5). In addition to fMRI, I used EEG, which provides superior time resolution and thereby an opportunity to discover biomarkers complementary to the underlying pathophysiology uncovered in fMRI studies. To date, there have been no studies investigating early visual processing in electrophysiological components in either AN or BDD groups, one key area of focus for my dissertation. In order to determine if individuals with AN and BDD have similar abnormalities in early holistic processing and slower detail processing relative to controls, I investigated amplitude and latency differences in early visual event related potentials (ERP), namely the P100 and N170.These components are thought to reflect configural and detailed processing, respectively, and are abnormal in those with schizophrenia (6) and William’s Syndrome (7), two disorders in which individuals may suffer from similar abnormalities in global processing. The results of reduced P100 amplitudes and delayed N170 latency suggests early visual processing deficiencies in AN. Moreover, there was evidence of a possible brain-behavior relationship in the BDD group, as worse insight correlated with reduced N170 amplitude.Next, I performed a joint analysis of EEG and fMRI signals using a technique called Fusion independent components analysis (ICA) to generate a joint spatiotemporal profile that leverages spatial and temporal resolution advantages of the respective modalities. This allowed us to localize early electrophysiological processes using the high spatial resolution of fMRI, and had yet to be performed in these populations. We found that AN and BDD showed hypoactivity in early and dorsal visual stream systems for low spatial frequencies, suggesting that a common deficiency in holistic processing is operating in primary visual structures as early as 100 ms post exposure and extends later in time (170 ms) into dorsal stream higher order regions. However, the patterns of hypoactivity are not identical; BDD but not AN additionally demonstrated hyperactivity compared to controls in ventral visual stream systems for high spatial frequency houses, and BDD showed hypoactivity in dorsal visual regions for low spatial frequency faces in comparison to participants with AN. Thus, an imbalance in detailed versus configural/holistic processing for non appearance-related stimuli may characterize both disorders, but the defect appears to be more pronounced in BDD. This dissertation contributes novel findings to the understanding of the pathophysiology underlying visual processing in these disorders, using methods that have not yet been performed in these populations. We found evidence of similar abnormalities between AN and BDD. There were also important differences in electrophysiological and hemodynamic signatures as well, which warrants further investigation. Further experiments that test other ERP components, frequency analyses, and simultaneous EEG-fMRI studies, and replication of the current findings in larger samples, will allow further characterization of neural signatures that can be used as possible biomarkers for more accurate diagnoses and treatment. Deeper understanding of the early visual processing mechanisms in AN and BDD could better inform perceptual treatments, and ERP or fMRI components may have the potential to be to used to track and monitor patient symptoms or disease severity in the future
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
Cognitive-behavioral therapy for obsessive–compulsive disorder: access to treatment, prediction of long-term outcome with neuroimaging
No full textDispelling 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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