1,720,960 research outputs found
Functional clustering in EEG photic and auditory driving in schizophrenia
No full textThe purpose of this study is to investigate the effects of photic and auditory stimuli on brain functions in schizophrenics by investigating the functional cluster (FC) of EEGs. We recorded EEGs using 16 electrodes oil 10 schizophrenic patients and on 10 normal controls during photic and auditory stimuli. We estimated FC would characterize the strongly interactive brain regions among many brain regions. FC refers to the brain regions that interact much more strongly among themselves than with the rest of the brain. Brain regions that belong to the same cluster are therefore all functionally involved while, presumably, the regions that belong to separate clusters are functionally unrelated. When photic and auditory stimuli are applied, the schizophrenic patients have a very similar cluster composed of the right temporal and occipital regions for both conditions, whereas the normal controls show the normally driven information stream from the posterior areas to the prefrontal cortex. Our findings may suggest that in schizophrenics the right temporal and occipital regions strongly interact with neuronal activities not only in the resting condition but also during the stimulation condition. In addition, this strong interaction supports the abnormal brain functional connectivity and the dysfunction of the cortical structure during photic and auditory stimuli. Our study shows the existence and different pattern of FCs for normal controls and schizophrenics. Thus, FC analysis would be a potential tool to investigate the simultaneous neuronal activity of human EEGs. (c) 2005 Elsevier B.V. All rights reserved
EEG in schizophrenic patients: mutual information analysis
No full textObjective: The aim of the present study is to assess information transmission between different cortical areas in schizophrenics by estimating the average cross mutual information (A-CMI) and to characterize the dynamical property of the cortical areas of schizophrenic patients from multi-channel EEG by establishing the auto mutual information (AMI). Methods: We recorded the EEG from 16 electrodes in 10 schizophrenic patients and 10 age-matched normal controls. We estimated the slope of the AMI to evaluate the complexity of the EEG signal from one electrode and the A-CMI values of all 16 X 16 pairs of electrodes were calculated to investigate the information transmission of different cortical areas in schizophrenic patients. Results: In T5 and C3 electrodes, the schizophrenic patients had lower complexity than normal controls. The schizophrenic patients had significantly higher interhemispheric and intrahemispheric A-CMI values than the normal controls. Conclusions: These results are consistent with previous findings that suggest left hemispheric hypotemporality and inter- and/or intrahemispheric overconnectivity in schizophrenics. Our results of the left hemispheric hypotemporality and the increased interhemispheric information transmission in temporal lobe may support the hypothesis that the abnormal laterlization in temporal lobe are due to left temporal lobe deficit in schizophrenic patients. (C) 2002 Published by Elsevier Science Ireland Ltd
Hemispheric laterality and dimensional complexity in schizophrenia under sound and light stimulation
No full textThe aim of the present study is to investigate the relationship between linear and non-linear activities in human electroencephalograms (EEGs) by examining the linear lateral asymmetry index and the correlation dimension as a non-linear measure of complexity and to typify the characteristics of EEGs between schizophrenic patients and normal controls. We recorded the EEG from 16 electrodes in 10 schizophrenics (6 males and 4 females) and 10 age-matched normal controls (10 males), and calculated their asymmetry indices. The asymmetry index shows which hemispheric activity is dominant through examination of interhemispheric pairs in the frequency domain with EEGs between two regions. We also estimated correlation dimension. Remarkably, lower dimensional complexities appeared on the brain regions, which had significantly lower brain activity, as determined by a lateral asymmetry analysis, in schizophrenics before sound and light (SL) stimulation. We may suggest the possibility of co-varying of both linear and non-linear properties. This co-varying phenomenon maintained after the SL stimulation. Furthermore, schizophrenic patients revealed opposite asymmetric patterns compared to normal controls, as well as reversal phenomena and abnormalities in the left frontal region when SL stimuli were applied. (C) 2003 Elsevier Science B.V. All rights reserved
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
Dispelling 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
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