1,720,954 research outputs found
The Chronometry of Time Processing in Visual and Premotor Cortices
Full text linkTime is the most elusive dimension of everyday experience; we cannot touch nor see time nevertheless time is embedded in any sensory experience of the world and we can surely perceive it. How time is extracted from sensory inputs, how it is processed and represented in the human brain is far from clear. During my PhD I have tried to understand how temporal information in the millisecond range is extracted from visual inputs; i.e. how it is encoded/read-out and perceived. Specifically, I have asked “when”, at which stage of temporal information processing (i.e., from sensory drive integration to duration recognition) visual and premotor areas, brain regions known to play a role in temporal computations, are engaged. Focusing on the chronometry of these areas in duration encoding, I tried to better understand the functional role of these areas and at the same time, using stimuli with different sensory load and different durations ranges I have tried to gain insight on the mechanisms underlying duration perception.
To test the chronometry of different areas in duration encoding I used Transcranial Magnetic Stimulation (TMS), that I have applied over visual and premotor areas at different timings from the onset (to the offset) of visual stimuli that had to be judged in duration. In other words, I assumed that TMS applied at different timings after visual stimulus onset would affect duration judgments differently depending on the involvement over time of the target area during the processing of temporal information.
The combination of high temporal resolution (paired-pulse) TMS and duration discrimination tasks allowed me to test: A. the chronometry of primary visual cortex (V1) and extrastriate area V5/MT during the encoding of visual stimuli with different sensory load i.e., empty intervals and filled durations (chapter 2). B. the chronometry of V1 and Supplementary Motor Area (SMA) in duration encoding and reading out of visual temporal information (chapter 4) and C. to test the existence of a topographic representation of time in SMA (chapter 5). Finally, the experimental data of chapters 2 and 4 were modeled using a recently developed leaky integration model (Toso et al., 2021). This model sees duration perception as a result of the leaking integration of a sensory drive from primary sensory cortex (in Chapter 3 a description of the model with the modelling of chapter 2’s data and in Chapter 4, experimental data and modelling)
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
Transcranial direct current stimulation of the medial prefrontal cortex dampens mind-wandering in men
Full text linkMind-wandering, the mind's capacity to stray from external events and generate task-unrelated thought, has been associated with activity in the brain default network. To date, little is understood about the contribution of individual nodes of this network to mind-wandering. Here, we investigated the role of medial prefrontal cortex (mPFC) in mind-wandering, by perturbing this region with transcranial direct current stimulation (tDCS). Young healthy participants performed a choice reaction time task both before and after receiving cathodal tDCS over mPFC, and had their thoughts periodically sampled. We found that tDCS over mPFC - but not occipital or sham tDCS - decreased the propensity to mind-wander. The tDCS-induced reduction in mind-wandering occurred in men, but not in women, and was accompanied by a change in the content of task-unrelated though, which became more related to other people (as opposed to the self) following tDCS. These findings indicate that mPFC is crucial for mind-wandering, possibly by helping construction of self-relevant scenarios capable to divert attention inward, away from perceptual reality. Gender-related differences in tDCS-induced changes suggest that mPFC controls mind-wandering differently in men and women, which may depend on differences in the structural and functional organization of distributed brain networks governing mind-wandering, including mPFC
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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