1,721,035 research outputs found
Transcranial magnetic stimulation reveals two cortical pathways for visual body processing
No full textVisual recognition of human bodies is more difficult for upside down than upright presentations. This body inversion effect implies that body perception relies on configural rather than local processing. Although neuroimaging studies indicate that the visual processing of human bodies engages a large fronto-temporo-parietal network, information about the neural underpinnings of configural body processing is meager. Here, we used repetitive transcranial magnetic stimulation (rTMS) to study the causal role of premotor, visual, and parietal areas in configural processing of human bodies. Eighteen participants performed a delayed matching-to-sample task with upright or inverted static body postures. Event-related, dual-pulse rTMS was applied 150 ms after the sample stimulus onset, over left ventral premotor cortex (vPMc), right extrastriate body area (EBA), and right superior parietal lobe (SPL) and, as a control site, over the right primary visual cortex (V1). Interfering stimulation of vPMc significantly reduced accuracy of matching judgments for upright bodies. In contrast, EBA rTMS significantly reduced accuracy for inverted but not for upright bodies. Furthermore, a significant body inversion effect was observed after interfering stimulation of EBA and V1 but not of vPMc and SPL. These results demonstrate an active contribution of the fronto-parietal mirror network to configural processing of bodies and suggest a novel, embodied aspect of visual perception. In contrast, the local processing of the body, possibly based on the form of individual body parts instead of on the whole body unit, appears to depend on EBA. Therefore, we propose two distinct cortical routes for the visual processing of human bodies
Investigating embodied representations of emotional expressions in ASD: A study with SEPs
No full textAutism Spectrum Disorder (ASD) is a neurodevelopmental condition characterised by difficulties in social
interaction and communication, as well as repetitive and restricted patterns of behaviour and interests
(American Psychiatric Association, 2000). Recent research suggests that differences in embodied
representations of emotional expressions might play a role in ASD. For instance, several empirical studies
show that recognition of emotional expressions [3], interoception [2] and physiological responses to social
stimuli [4] function differently in ASD individuals. However, the neural mechanisms involved in atypical
embodied representations of emotional expression in ASD has not been systematically investigated.
Recent research highlights that visual perception of faces and bodies in typical population is accompanied
by parallel activity of visual and somatosensory areas [1, 5-8]. Our EEG study provides the first direct
measurement of the activity of the somatosensory cortex during perception of facial emotional
expressions in ASD individuals. Our methodology combines Visual and Somatosensory Evoked Potentials
(VEPs and SEPs), to isolate effects driven by somatosensory or visual processing. This methodology has
already provided evidence of unique contributions of the somatosensory cortex in processing emotional
expressions by Sel et al [8] and we are now interested in investigating whether ASD population show
different patterns of neural response compared to typical individuals. We are analyzing responses in visual
and somatosensory cortical areas in a group of ASD and a control TD participants while they perform a
visual emotion recognition task and a control gender recognition task. We predict a modulation of
somatosensory evoked potentials driven by emotional expressions processing but not by gender.
Moreover, we expect to observe a significant difference in this effect across the two groups
Embodied representations of emotional expressions in ASD
No full textAutism Spectrum Disorder (ASD) is a group of neurodevelopmental disorders characterised by social interaction and communication impairments, as well as repetitive and restricted patterns of behaviour (American Psychiatric Association, 2000). Recent research suggests that differences in representations of emotional expressions might play a role in ASD. Evidence for early atypical modulation of emotional expressions in visual areas has been shown (Batty et al.,2011). Moreover, recent research has highlighted that impaired embodied representations of emotions might also be atypical in ASD. In fact, reduced embodied simulation of emotional expressions in ASD has been highlighted by neuroimaging studies (Dapretto et al., 2006) and physiological responses to social stimuli seem to be atypical in ASD individuals (Hirsten & Ramachandran, 2001). Nevertheless, a selective impairment of embodied representations of emotional expressions in the somatosensory cortex in ASD has not been investigated yet.
Our methodology combines Visual and Somatosensory Evoked Potentials (VEPs and SEPs) to isolate embodiment effects driven by somatosensory or visual processing. This methodology has already provided evidences of the involvement of the somatosensory cortex in processing emotional expressions in typical populations (Sel et al., 2014), and we are now interested in investigating whether ASD population show different patterns of responses compared to typical population. We are measuring visual and somatosensory responses in two groups of ASD and TD while they perform visual emotion recognition task and a control gender recognition task. Preliminary data will be presented, we expect to find a differential modulation of emotional expressions in the visual and somatosensory evoked potentials across the two groups
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
Extrastriate body area underlies aesthetic evaluation of body stimuli
Full text linkHumans appear to be the only animals to have developed the practice and culture of art. This practice presumably relies on special processing circuits within the human brain associated with a distinct subjective experience, termed aesthetic experience, and preferentially evoked by artistic stimuli. We assume that positive or negative aesthetic judgments are an important function of neuroaesthetic circuits. The localization of these circuits in the brain remains unclear, though neuroimaging studies have suggested several possible neural correlates of aesthetic preference. We applied repetitive transcranial magnetic stimulation (rTMS) over candidate brain areas to disrupt aesthetic processing while healthy volunteers made aesthetic preference judgments between pairs of dance postures, or control non-body stimuli. Based on evidence from visual body perception studies, we targeted the ventral premotor cortex (vPMC) and extrastriate body area (EBA), in the left and right hemispheres. rTMS over EBA reduced aesthetic sensitivity for body stimuli relative to rTMS over vPMC, while no such difference was found for non-body stimuli. We interpret our results within the framework of dual routes for visual body processing. rTMS over either EBA or vPMC reduced the contributions of the stimulated area to body processing, leaving processing more reliant on the unaffected route. Disruption of EBA reduces the local processing of the stimuli, and reduced observers’ aesthetic sensitivity. Conversely, disruption of the global route via vPMC increased the relative contribution of the local route via EBA, and thus increased aesthetic sensitivity. In this way, we suggest a complementary contribution of both local and global routes to aesthetic processing
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
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