1,720,983 research outputs found
Neuroimaging and neurocognitive assessment of PTSD and MDD in a South African community setting
Get PDFBackground: There is growing evidence of abnormalities in neurocognition, neuroanatomy, and functional connectivity in posttraumatic stress disorder (PTSD) and major depressive disorder (MDD). However, there has been less work on individuals who suffer with comorbid PTSD and MDD. It is important to investigate the neurobiology of this overlap because of its prevalence, its associated morbidity, and the hope that it may shed more light on the mechanisms involved in each disorder, including the role of the prefrontal regions. This dissertation tests the hypothesis that women with PTSD and MDD display distinct patterns of neurocognitive impairment and associated brain dysfunction, relative to healthy controls, and these effects will be amplified in patients with both disorders. Methods: This dissertation was undertaken within the Drakenstein Child Health Study, a study exploring child health determinants in mother-infant dyads from the Drakenstein district, Western Cape. Mothers (between 18 and 50 years) were recruited and divided into 4 groups: PTSD, MDD, PTSD with MDD, and healthy controls. Participants were assessed using the computerised NIH Toolbox, and paper and pencil neurocognitive tests. Domains assessed included memory, learning, and processing speed, and with particular focus on executive function and attention domains. Participants underwent resting-state functional imaging as well as structural brain imaging. Functional connectivity within and between cognitive control networks (salience network, dorsal attention network, and frontoparietal networks) and a default mode network were compared across the 4 groups. Neuroanatomical indices (cortical thickness, volume, and surface area) of 10 frontal cortical regions from the Desikan-Killiany atlas in Freesurfer 6 were analysed across the 4 groups. Results: All three clinical groups demonstrated no group differences on measures of attention and executive function, diagnoses of PTSD and MDD were associated with more intrusive thoughts and delayed recall impairment, respectively. However, neurocognitive findings indicate that PTSD with comorbid MDD is not associated with greater neurocognitive dysfunction relative to mono-diagnostic groups. Abnormal resting-state connectivity was observed for the MDD group in the default mode network, and for both comorbid and MDD patient groups within frontoparietal networks. Abnormal salience network connectivity for the comorbid group was observed when examining performance on the Pattern Comparison Processing Speed test. No between-network connectivity group differences were observed. Surface area and volume reductions of prefrontal regions were evident for PTSD and MDD, however, no volumetric and surface area differences were observed for the comorbid group. Conclusion: In this sample of mothers from a low-middle income region, distinct patterns of neurocognitive dysfunction and impairment in PTSD, MDD, and PTSD with MDD were observed. However, contrary to hypotheses, comorbidity is not associated with greater dysfunction and impairment and the associations of PTSD and comorbid MDD are not amplified in this sample. These findings have implications for the development of treatment plans for patients diagnosed with PTSD, MDD, and PTSD with comorbid MDD, so that interventions are tailored in a way that is responsive to differences between these groups in the presentation of neurocognitive profile, brain function, and structure
Dreaming in Urbach-Wiethe patients the effect of amygdala damage on dreaming
No full textIncludes bibliographical references.As it stands, there is a paucity of literature looking at the effect of damaged amygdalae on dreaming and dream content. Of the many functions, the amygdala is heavily involved in processing emotional stimuli and fear conditioning. In Revonsuo’s threat simulation theory (TST), the amygdala plays an important role in the threat simulation mechanism. This mechanism evaluates the threatening situation, then chooses and executes the avoidant type behaviour to successfully avoid the potential threat. All of this is done in the dream world to ensure that humans have a safe virtual environment in which to practice these responses. To test this theory, a sample of people without a functioning amygdala was needed. Unfortunately, bilateral amygdala lesions are extremely rare in the human population. Urbach-Wiethe disease (UWD) is a rare, autosomal recessive disorder that presents with characteristic amygdala calcifications. A sample of 8 UWD patients and 8 matched controls (all females) from the Northern Cape in South Africa were used
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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