1,720,990 research outputs found
“Left and right prefrontal routes to action comprehension”
Full text linkSuccessful action comprehension requires the integration of motor information and semantic cues about objects in context. Previous evidence suggests that while motor features are dorsally encoded in the fronto-parietal action observation network (AON); semantic features are ventrally processed in temporal structures. Importantly, these dorsal and ventral routes seem to be preferentially tuned to low (LSF) and high (HSF) spatial frequencies, respectively. Recently, we proposed a model of action comprehension where we hypothesized an additional route to action understanding whereby coarse LSF information about objects in context is projected to the dorsal AON via the prefrontal cortex (PFC), providing a prediction signal of the most likely intention afforded by them. Yet, this model awaits for experimental testing. To this end, we used a perturb-and-measure continuous theta burst stimulation (cTBS) approach, selectively disrupting neural activity in the left and right PFC and then evaluating the participant's ability to recognize filtered action stimuli containing only HSF or LSF. We find that stimulation over PFC triggered different spatial-frequency modulations depending on lateralization: left-cTBS and right-cTBS led to poorer performance on HSF and LSF action stimuli, respectively. Our findings suggest that left and right PFC exploit distinct spatial frequencies to support action comprehension, providing evidence for multiple routes to social perception in humans
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
Le viti native americane e asiatiche. Ibridi portinnesti e varietali.
No full textLe viti americane e asiatiche. Ibridi portinnesti e varietali
Improvements in the identification of archaeological buried feature in QuickBird imagery and in ground magnetic data
No full textVariations 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
Autistic traits predict poor integration between top-down contextual expectations and movement kinematics during action observation
Full text linkAutism is associated with difficulties in predicting and understanding other people's actions. There is evidence that autistic traits are distributed across a spectrum and that subclinical forms of autistic impairments can also be measured in the typical population. To investigate the association between autistic traits and motor responses to others' actions, we quantified these traits and measured cortico-spinal excitability modulations in M1 during the observation of actions embedded in congruent, incongruent and ambiguous contexts. In keeping with previous studies, we found that actions observed in congruent contexts elicited an early facilitation of M1 responses, and actions observed in incongruent contexts, resulted in a later inhibition. Correlational analysis revealed no association between autistic traits and the facilitation for congruent contexts. However, we found a significant correlation between motor inhibition and autistic traits, specifically related to social skills and attention to details. Importantly, the influence of these factors was independent from each other, and from the observer's gender. Thus, results suggest that individuals with higher social deficits and greater detail-processing style are more impaired in suppressing action simulation in M1 when a mismatch between kinematics and context occurs. This points to difficult integration between kinematics and contextual representations in the autistic-like brain
Spatial frequency tuning of motor responses reveals differential contribution of dorsal and ventral systems to action comprehension
Full text linkfirst published May 26, 2020Understanding object-directed actions performed by others is central
to everyday life. This ability is thought to rely on the interaction
between the dorsal action observation network (AON) and a
ventral object recognition pathway. On this view, the AON would
encode action kinematics, and the ventral pathway, the most likely
intention afforded by the objects. However, experimental evidence
supporting this model is still scarce. Here, we aimed to disentangle
the contribution of dorsal vs. ventral pathways to action
comprehension by exploiting their differential tuning to lowspatial
frequencies (LSFs) and high-spatial frequencies (HSFs). We
filtered naturalistic action images to contain only LSF or HSF and
measured behavioral performance and corticospinal excitability
(CSE) using transcranial magnetic stimulation (TMS). Actions were
embedded in congruent or incongruent scenarios as defined by
the compatibility between grips and intentions afforded by the
contextual objects. Behaviorally, participants were better at discriminating
congruent actions in intact than LSF images. This effect
was reversed for incongruent actions, with better performance for
LSF than intact and HSF. These modulations were mirrored at the
neurophysiological level, with greater CSE facilitation for congruent
than incongruent actions for HSF and the opposite pattern for
LSF images. Finally, only for LSF did we observe CSE modulations
according to grip kinematics. While results point to differential
dorsal (LSF) and ventral (HSF) contributions to action comprehension
for grip and context encoding, respectively, the negative congruency
effect for LSF images suggests that object processing may
influence action perception not only through ventral-to-dorsal
connections, but also through a dorsal-to-dorsal route involved
in predictive processing.This work was supported by grants from the
European Commission (MCSA-H2020-NBUCA; Grant 656881) (to L.A.), from
the Italian Ministry of University and Research (PRIN 2017; Protocol
2017N7WCLP) (to C.U.), and from the Italian Ministry of Health (Ricerca
Corrente 2020, Scientific Institute, IRCCS E. Medea) (to A.F.)
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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