1,721,300 research outputs found
The role of molecular analyses in the diagnosis and treatment of non-small-cell lung carcinomas
No full textNon-small-cell lung cancer (NSCLC) subtyping has recently been a key factor in determining patient management with novel drugs. In addition, the identification of distinct oncogenic driver mutations frequently associated with NSCLC histotype and coupled to the clinical responses to targeted therapies have revolutionized the impact of histologic type and molecular biomarkers in lung cancer. Several molecular alterations involving different genes (EGFR, KRAS, ALK, BRAF, and HER2) seem to have a remarkable predilection for adenocarcinoma and specific inhibitors of EGFR and ALK are now available for patients with adenocarcinoma harboring the relevant gene alterations. The efficacy of histology-based and molecular-targeted therapies had a deep impact in (1) re-defining classification of lung cancer (particularly adenocarcinomas) and (2) routine clinical practice of pathologists involved in optimization of handling of tissue samples in order to guarantee NSCLC subtyping with the help of immunohistochemistry and adequately preserve tumor cells for molecular analysis. In agreement with the modern multidisciplinary approach to lung cancer, we reviewed here the diagnostic and predictive value of molecular biomarkers according to the clinical, pathologic, and molecular biologist viewpoints
Network connectivity correlates of variability in fluid intelligence performance
No full textAbstract
Abstract reasoning requires a pattern of spatial and temporal coordination among regions across the entire brain. Recent evidence suggests a very high similarity between spontaneous and evoked brain activity in humans, implying that a fine characterization of brain dynamics recorded during resting-state might be informative for the understanding of evoked behavior. In a recent work, we listed and detailed the sets of regions showing robust co-activation during the solution of fluid intelligence (gf) tasks, decomposing such meta-analytic maps in stimulus- and reasoning stage-specific sub-maps. However, while anatomical overlap with well-known resting-state fMRI networks (RSNs) has been documented, we here propose a quantitative validation of such findings via functional connectivity analysis in a sample of healthy participants. Results highlight a striking degree of similarity between the connectivity profile of the gf network and that of the dorsal attention network, with additional overlap with the left and right fronto-parietal control networks. Interestingly, a strong negative correlation with structures of the default mode network (DMN) was also identified. Results of regression models built on two independent fMRI datasets confirmed the negative correlation between gf regions and medial prefrontal structures of the DMN as a significant predictor of individual gf scores. These might suggest a framework to interpret previously reported aging-related decline in both gf and the correlation between “task-positive” networks and DMN, possibly pointing to a common neurophysiological substrate
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
Editorial: ‘Non-invasive brain stimulation and plasticity changes in aging’
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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
State-dependent Transcranial Magnetic Stimulation (TMS) protocols
No full textIn this chapter we describe a novel approach which enhances the functional resolution of transcranial magnetic stimulation (TMS) to a level that allows for differential stimulation of functionally distinct neuronal populations within a cortical area. It is based on the well-known principle of state - dependency : a phenomenon whereby the response of a system to an external stimulus is affected not only by the properties of that stimulus but also by the internal state of the system. With regard to TMS, the neural impact of an applied pulse is determined not only by the stimulation parameters but also by the initial activation state of the affected neurons; therefore, neurons within a cortical area will be differentially affected by TMS if their initial activation states at the time of stimulation are dissimilar. The basic idea in state-dependent TMS is to control this initial state/TMS interaction. By selectively increasing the susceptibility of a specific neuronal population via adaptation and priming, one can differentially stimulate this population from other neurons in the area. The main benefit of state-dependent TMS is that it allows TMS research to move beyond questions of “Is region X necessary for task Y” and investigate the functional neuronal properties within a targeted area. So far, this approach has been successfully used to investigate neuronal representations associated with a wide range of cognitive functions such as numerical cognition, action observation, and conceptual knowledge, and it may hold much promise for future research
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
M1 contributes to the intrinsic but not the extrinsic components of motor skills
No full textProcedural skills consist of several components that can be simultaneously acquired. During a motor-learning task we can distinguish between how a movement is performed (intrinsic component) and the spatial-related (extrinsic) component of this movement. The intrinsic movement component is thought to be supported by motor loops, including primary motor cortex (M1) as assessed with neuroimaging studies. Here we want to test further whether M1 makes a critical contribution to the movement rather than spatial-related component of skill learning. To this purpose, we used repetitive Transcranial Magnetic Stimulation (rTMS) and the serial reaction time (SRT) task. Twenty right-handed participants performed the SRT-task starting with their left or right hand. After this learning session, participants switched to the untrained hand by performing original (spatial-related) and mirror-ordered (movement-based) sequences. rTMS was applied to M1 ipsi- or contralateral to the transfer hand and both sequences were retested. Results revealed rTMS-interference with motor-skill transfer of mirror-ordered but not original sequences, showing that M1 is critically involved in the retrieval/transformation of the intrinsic but not the extrinsic movement coordinates. rTMSinterference in the mirror-condition consisted of both (i) disruption and (ii) release of motor skill transfer depending on the stimulated hemisphere and on transfer-hand. The pattern of results suggests (i) contralateral (right) M1 involvement in retrieval/transformation of motor information during left hand reproduction of previously acquired right-hand motor-skills; and (ii) modulatory interactions of inhibitory nature from the dominant (left) to the non-dominant (right) M1 in the same transfer condition. These results provide further evidence that M1 is essential to intrinsic movement-based skill-learning and novel insight on models of motor learning and hemispheric specialization, suggesting the involvement of interhemispheric inhibition
Dissecting the parieto-frontal correlates of fluid intelligence: A comprehensive ALE meta-analysis study
No full textRecent advances in cognitive neuroscience have shown how experience-independent cognitive abilities termed fluid intelligence (Gf) can predict academic achievement, longevity and resilience to neurodegeneration. Therefore, the understanding of the neurobiological underpinnings of Gf becomes a crucial step for the implementation of cognitive rehabilitation as well as enhancement interventions. Here we present the result of a quantitative meta-analysis of available fMRI and PET literature about Gf in humans, including (i) distinct maps for verbal and visuospatial stimuli, (ii) an analysis of brain regions contributing to processing of more complex stimuli as well as (iii) a model-driven distinction of processing stages occurring during Gf-related problem solving. Results highlight the loading of Gf components over functionally defined resting-state fMRI networks, with different degrees of overlap in both hemispheres and subcortical structures. A major role for nodes of the dorsal attention network during both verbal and visuospatial abstract reasoning tasks represents the most consistent correlate of Gf, with additional contributions by regions of the anterior salience and left fronto-parietal control network. Increase in trial difficulty elicits a more pronounced engagement of the language and left fronto-parietal control networks, while inferring the rules subtending a given Gf task relies on a different anatomo-functional substrate than producing novel solutions. Current findings might allow a clearer association between Gf-related activity and brain connectivity, also providing quantitative ALE maps to be used in network-based brain stimulation and cognitive training interventions
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