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Brain Asymmetries: the lateralization of three different cognitive processes
Get PDFThe hemispheric lateralization has received attention across years because its implication in determine behavioural and individual differences. Specifically, the left hemisphere’s expansion and specialization in the course of the evolution received a lot of attention for its involvement in language functioning. Nevertheless, also the right hemisphere expanded and, in particular, the right parietal lobe increased its dimension and its connections, becoming a specialized area for the multisensory integration mechanisms. Even if the parietal lobe has been extensively studied, there are still unanswered questions about the lateralization of different cognitive processes related to this area.
Given the broad implication of the parietal areas in several cognitive processes, in this thesis three stand-alone studies on healthy population are presented. The studies are independent even if all of them aim at exploring the lateralization of cognitive processes typically related to the parietal areas. A hierarchical structure was followed from the most basic to the most complex cognitive process: (i) visuo-spatial attention, (ii) motor behaviour and (iii) body representation.
In the first study, thirty-six right- and left-handers participants were tested during perceptual (Line Bisection) and representational (Mental Number Line) tasks. Taking into consideration the attentional bias (pseudoneglect), results showed a greater difference between the perceptual and representational domains in the left-handers group. This difference is led by a bias farther to the left in the representational domain, but not in the perceptual one, compared to right-handers. These results suggest that right- and left-handers are differently affected by attentional asymmetries depending on the domain being representational or perceptual.
The second study aimed at exploring the lateralization of the bimanual temporal coupling effect. Thirty-two participants were tested during a bimanual task while the transcranial Direct Current Stimulation was applied over right and left parietal area. Results highlight different effects of the stimulation depending on the level of complexity of the movement.
In the third study, eighteen participants were tested during implicit (not requiring awareness) and explicit (requiring awareness) body-schema related tasks while a cathodic or sham transcranial Direct Current Stimulation was delivered on the right parietal area. Results highlight an effect of stimulation specific for the implicit task, and selective for identification processes rather than widespread to motor related aspects. These results challenge the general idea of a right hemispheric dominance, and rather suggest that body schema processes rely on a bilateral network dependent on awareness encompassing both the left and the right hemisphere.
The three studies together highlight that a black or white hemispheric lateralization of cognitive processes related to parietal areas is not feasible at this point. Indeed, specific features (domain, complexity and awareness) play an important role in concluding for a right or left dominance. For this reason, future studies are needed in order to clarify their weight using different techniques together
Multiple dissociations in patients with disorders of body awareness: Implications for the study of consciousness
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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
Neuroimaging Studies on Disorders of Consciousness : a Meta-Analytic Evaluation
Get PDFNeuroimaging tools could open a window on residual neurofunctional activity in the absence of detectable behavioural responses in patients with disorders of consciousness (DOC). Nevertheless, the literature on this topic is characterised by a large heterogeneity of paradigms and methodological approaches that can undermine the reproducibility of the results. To explicitly test whether task-related functional magnetic resonance imaging (fMRI) can be used to systematically detect neurofunctional differences between different classes of DOC, and whether these differences are related with a specific category of cognitive tasks (either active or passive), we meta-analyzed 22 neuroimaging studies published between 2005 and 2017 using the Activation Likelihood Estimate method. The results showed that: (1) active and passive tasks rely on well-segregated patterns of activations; (2) both unresponsive wakeful syndrome and patients in minimally conscious state activated a large portion of the dorsal-attentional network; (3) shared activations between patients fell mainly in the passive activation map (7492 voxels), while only 48 voxels fell in a subcortical region of the active-map. Our results suggest that DOCs can be described along a continuum-rather than as separated clinical categories-and characterised by a widespread dysfunction of brain networks rather than by the impairment of a well functionally anatomically defined one
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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