1,721,084 research outputs found
DUAL ROLE OF SNAP-25 AT PRE- AND POST-SYNAPTIC LEVEL DURING DEVELOPMENT
Full text linkImpairment of synaptic function can lead to neurological and psychiatric disorders collectively referred to as synaptopathies. SNAP-25, a SNARE protein controlling synaptic vesicle exocytosis and fundamental presynaptic functions, is implicated in several brain pathologies and, indeed, brain areas of psychiatric patients often display reduced SNAP-25 expression.
We observed that halved SNAP-25 levels at 13–14DIV not only fail to impair synaptic transmission, but instead enhance evoked glutamatergic neurotransmission. This effect is probably dependent on presynaptic voltage-gated calcium channel activity and it is not followed by changes in spontaneous quantal events or in the pool of readily releasable synaptic vesicles. Notably, synapses of neurons with reduced SNAP-25 levels show paired-pulse depression as opposed to paired-pulse facilitation occurring in their wild-type counterpart. These phenotypes disappear with synapse maturation, where instead a reduction of evoked glutamatergic transmission and mEPSC amplitude emerge in heterozygous neurons thus suggesting the onset of a postsynaptic defect. In fact, it has been recently reported that a peculiar postsynaptic SNARE complex is required for long-term potentiation; however, the role of SNAP-25 in this process is not completely understood. We recently demonstrated that acute down-regulation of SNAP-25 in vitro affects spine morphogenesis through binding to p140Cap, thus suggesting that the protein may exert a structural role at the postsynaptic level. Here we demonstrate that in vivo acute down-regulation of SNAP-25 in CA1 hippocampal neurons affects spine number and morphology and causes a specific reduction of the postsynaptic protein PSD-95. Consistently, hippocampal neurons from SNAP-25 het mice show a flawed maturation of postsynaptic specializations, reduced densities of dendritic spines and defective PSD-95 clustering. These effects do not stem from impaired presynaptic function, but as a direct consequence of reduced SNAP-25 levels in the postsynaptic compartment. By co-immunoprecipitation and LUMIER Assay, we show that SNAP-25, PSD-95 and p140Cap are part of the same molecular complex in the brain, with p140Cap being intrinsically capable to bind either to SNAP-25 and PSD-95. These data provide new mechanistic insights as to SNAP-25 involvement in synaptopathies that go beyond the protein’s known roles in presynaptic function
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
From filopodia to synapses : the role of actin-capping and anti-capping proteins
Full text linkActin-capping and anti-capping proteins are crucial regulators of actin dynamics. Recent studies have indicated that these proteins may be heavily involved in all stages of synaptogenesis, from the emergence of filopodia, through neuritogenesis and synaptic contact stabilization, to the structural changes occurring at the synapse during potentiation phenomena. In this review, we focus on recent evidence pointing to an active role of actin-capping and anti-capping proteins in orchestrating the processes controlling neuronal connectivity and plasticity
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