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A structural magnetic resonance imaging studyof Orbitofrontal Cortex in Psychosis
Full text linkABSTRACT
BACKGROUND: La corteccia Orbitofrontale (OFC) è la parte più inferiore e ventrale della corteccia prefrontale ed è situata tra le orbite degli occhi. Grazie alle sue connessioni con l’amigdala, l’ippocampo, il talamo, la corteccia prefrontale dorso laterale e il lobo temporale superiore, è coinvolta in numerosi processi cognitivi come l’integrazione sensoriale, meccanismi di ricompensa e punizione, decision-making, regolazione delle emozioni e controllo degli impulsi. Lesioni alla OFC producono deficit cognitivi, affettivi e sociali simili a quelli presenti nella schizofrenia. Anche se con qualche inconsistenza, esistono evidenze di una riduzione di volume della OFC nella schizofrenia, e questa riduzione sembra associata con la psicopatologia e con alterazioni della cognizione. Tuttavia, non è ancora chiaro se queste riduzioni di volume sono presenti prima dell’insorgere della malattia o se insorgono con il progredire della stessa.
OBIETTIVI: Gli obiettivi dello studio erano misurare i volumi della OFC e delle sue sottoaree, tracciati sulle immagini di risonanza magnetica, in un gruppo di pazienti affetti da schizofrenia (SCZ), in un gruppo di pazienti all’esordio psicotico (FEP), reclutati all’interno del progetto “Psychosis Incident Cohort Outcome Study” (PICOS), e in un gruppo di controlli sani (HC) e di studiare i cambiamenti nel tempo dei volumi della OFC in questo campione.
METODI: Sono state raccolte le variabili sociodemografiche e cliniche di 26 pazienti con schizophrenia, 16 pazienti all’esordio e 21 controlli sani. Le sessioni di risonanza magnetica sono state condotte tramite uno scanner 1,5 T e le immagini sono state analizzate mediante il software BRAINS2. I soggetti hanno effettuato una seconda risonanza dopo un periodo medio di 3 anni. La OFC e le sue sottoaree sono state tracciate e segmentate in sostanza grigia e bianca.
RISULTATI: Nel confronto trasversale, il volume della sostanza bianca e di quella grigia della parte laterale sinistra della OFC erano maggiori negli SCZ, rispetto ai FEP e ai HC. Nel confronto longitudinale, il volume della sostanza grigia della OFC dei FEP ha avuto un maggior decremento nel tempo rispetto a quello degli SCZ e dei HC.
DISCUSSIONE: La parte laterale sinistra della OFC sembra una regione particolarmente interessata da alterazioni volumetriche nella schizofrenia. La riduzione nel tempo di sostanza grigia della OFC nei FEP sembra confermare l’ipotesi che il volume cerebrale è maggiormente affetto da riduzione nella prima fase della malattia.ABSTRACT
BACKGROUND: The orbitofrontal cortex (OFC) is the most inferior and ventral region of the prefrontal cortex that lies above the orbits. Through its connections with the amygdala, hyppocampus, thalamus, dorsolateral prefrontal cortex and superior temporal lobe, it is involved in several cognitive processes, such as sensory integration, reward mechanism, decision-making, mood regulation and impulse control. OFC dysfunction is implicated in cognitive, affective and social impairments similar to those present in schizophrenia. Although with some inconsistencies, there is evidence that OFC volumes are reduced in schizophrenia, and that they may be associated with psychopathology and altered cognition. However, it is still not clear whether OFC deficits are present before the onset of the disease or whether they occur with the progression of the illness.
OBJECTIVES: The aims of the study were to measure the volumes of the OFC and its subregions, as traced on MRI scans, in a group of schizophrenia patients (SCZ), in a group of First Episode Psychosis patients (FEP), recruited in the context of the Psychosis Incident Cohort Outcome Study (PICOS), and a in group of healthy controls (HC) and to investigate the changes in OFC volumes over time in this cohort.
METHODS: socio-demographical and clinical data were initially acquired from 26 SCZ patients, 16 FE patients and 21 HC subjects. The MRI sessions were conducted using a 1.5 T scanner and the images were analyzed using the BRAINS2 software. Subjects were scanned the second time after a mean follow up period of 3 years. The OFC and its medial and lateral subregions were traced and they were segmented for grey and white matter.
RESULTS: In the cross sectional comparison, both the white and grey matter of the left lateral OFC was found to be increased in SCZ patients in respect to FEP patients and HC. In the longitudinal comparison the OFC grey matter volume of FEP patients had a greater decrease across time than those of chronic SCZ patients and HC.
DISCUSSION: The left lateral OFC seems to be a brain region particularly affected by volume alteration in schizophrenia. The OFC grey matter reduction in FEP patients across time might confirm the assumption that brain volume is more affected by loss in the very first time of the illness
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
Specific linguistic and pragmatic deficits in Italian patients with schizophrenia
No full textOBJECTIVE:Verbal communication impairments are prominent features of schizophrenia. The grammatical and pragmatic components of expressive and receptive verbal abilities were systematically examined, for the first time, in Italian patients with schizophrenia. Indeed, most of the language literature is composed of studies on English speaking people.METHOD:Elicited narrative production, and syntactic and pragmatic receptive abilities were analyzed in a cohort of 37 patients with schizophrenia and 37 healthy controls. Furthermore, a conversational speech production task was administered to an age- and gender-matched subset of this population. The level of significance was set at
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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