1,720,964 research outputs found
Brain-Behavior Relationship in a Case of Successful ECT for Drug Refractory Catatonic OCD
No full textAbstract: This case report describes the successful response to electroconvulsive therapy (ECT) in a patient with an unusual presentation of catatonia, whose onset occurred in the context of an extremely severe form of refractory obsessive-compulsive disorder (OCD). We correlated the clinical improvement in catatonic and OCD symptoms with specific changes in brain function as shown by regional cerebral blood flow scans, neurological soft signs examination, and neuropsychological testing. All assessments were conducted before and after the ECT course. The results strongly suggest that a right hemisphere dysfunction was the neural correlate of our patient’s symptoms, and that ECT, by reverting this abnormality, may serve as an effective therapeutic approach for refractory catatonic OCD
Gilles de la Tourette syndrome and voluntary movement: A functional MRI study
No full textTourette syndrome (TS) is hypothesised to be caused by an abnormal organization of movement control. The aim of this study was to use functional magnetic resonance imaging to study motor cortex activation in a TS patient. Usual and unusual self-paced voluntary movements were performed. The TS patient displayed supplementary motor area (SMA) activation during both tasks. This activation reflects a continuous use of the SMA to perform the voluntary motor movements required in both tasks. Moreover, the absence of tics during the execution of these voluntary motor tasks suggests that tic activity may be suppressed by additional mental effort. (c) 2005 Elsevier Ireland Ltd. All rights reserved
A chemical shift imaging study on regional metabolite distribution in a CADASIL family
No full textAbstract A chemical shift imaging (CSI) study was performed to directly assess relative concentrations of N-acetylaspartate (NAA), Cho and Cr metabolites in normal- and abnormal-appearing brain tissue of asymptomatic and symptomatic members of a single family with a neuropathologic, genetic and electrophysiological confirmed diagnosis of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. The aim of the investigation was to evaluate clinical findings and metabolite abnormalities as early appearance of axonal injury in this syndrome. The main findings related statistically significant decreases in the mean metabolite ratios for NAA/Cr, NAA/Cho and Cho/Cr in the anterior parts in comparison with the posterior parts of the centrum semiovale in symptomatic and asymptomatic patients. The effect was considerably greater in the symptomatic patients, indicating a strong correlation between CSI and pathology results. No differences were found between the two areas in the control group. Although lactate signals were hardly detectable in individual spectra, there was a trend toward increased Lac/Cr values in the anterior parts with respect to the posterior parts in the patient group, with the effect particularly evident in the asymptomatic subjects with the gene mutation
Identification of activated regions during a language task
No full textFunctional magnetic resonance imaging (fMRI) techniques are based on the assumption that changes in neural activity are accompanied
by modulation in the blood-oxygenation-level-dependent (BOLD) signal. In addition to conventional increases in BOLD signals, sustained
negative BOLD signal changes are occasionally observed in many fMRI experiments, which show regions of cortex that seem to respond in
antiphase with primary stimulus. The existence of this so-called negative BOLD response (NBR) has been observed and investigated in many
functional studies. Several theoretical mechanisms have been proposed to account for it, but its origin has never been fully explained.
In this study, the variability of fMRI activation, including the sources of the negative BOLD signal, during phonological and semantic
language tasks, was investigated in six right-handed healthy subjects. We found significant activations in the brain regions, mainly in the left
hemisphere, involved in the language stimuli [prominent in the inferior frontal gyrus, approximately Brodmann Areas (BA)7, BA44, BA45
and BA47, and in the precuneus]. Moreover, we observed activations in motor regions [precentral gyrus and supplementary motor area
(SMA)], a result that suggests a specific role of these areas (particularly the SMA) in language processing. Functional analysis have also
shown that certain brain regions, including the posterior cingulate cortex and the anterior cingulate cortex, have consistently greater activity
during resting states compared to states of performing cognitive tasks. In our study, we observed diffuse NBR at the cortical level and a
stronger negative response in correspondence to the main sinuses. These phenomena seem to be unrelated to a specific neural activity,
appearing to be expressions of a mechanical variation in hemodynamics. We discussed about the importance of these responses that are
anticorrelated with the stimulus. Our data suggest that particular care must be considered in the interpretation of fMRI findings, especially in
the case of presurgical studies
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
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