1,720,967 research outputs found
Data from: 'Mobile EEG reveals functionally dissociable dynamic processes supporting real-world ambulatory obstacle avoidance: Evidence for early proactive control'
No full textThis dataset is related to the article entitled 'Mobile EEG reveals functionally dissociable dynamic processes supporting real‐world ambulatory obstacle avoidance: Evidence for early proactive control' accepted for publication by the European journal of Neuroscience on January 19th 2021 (https://doi.org/10.1111/ejn.15120). The dataset includes pre processed (mobile) EEG data of 32 healthy participants (age range 19-65) during an obstacle avoidance task in four different conditions (the name of the files match the name of the conditions in the article): free (no obstacles), pre (pre-set adjustment), far (delayed adjustment) and near (early adjustment). Data are segmented around 'OBSTACLE' event.Dataset included the EEG files of 32 healthy participants in 4 different exerimental conditions (32 x 4 for a total of 128 EEG files, .set and .fdt format). Each file is named as 'Sub', number ('_1') and condition ('_free', '_pre', '_far', '_near')
Action selection uncertainty in the test phase of a transitive inference task: Neuronal correlates in monkey premotor cortex.
No full textCognitively advanced animals are able to dynamically interact with the environment. In this process, action selection could be strongly influenced by the confidence value assigned to single items in the stream of incoming sensory information.
A form of dynamic representation of the environment is the organization of learned items in hierarchically ordered series. In a 6-items transitive inference task, when the list A > B > C > D > E > F is finally created, the probability of choosing B in the pair BC is lower than for the pair BE suggesting that the confidence for the value of B is variable and related to the mental representation of all other elements presented/experienced together. This relationship between performance and symbol separation is also know as symbolic distance effect.
Previous work has focused on the contribution of sensory information to confidence. We explored how confidence on target value could influence action selection by measuring neuronal activity in the premotor cortex of 2 trained monkeys. We selected neurons with activity modulated by the direction of movement and we analyzed how directionality is influenced by the symbolic distance of items to compare. Our results show that directionality in premotor cortex increases with symbolic distance and uncertainty providing support to the idea that the motor system contributes to perceptual confidence
Action selection uncertainty in the test phase of a transitive inference task: Neuronal correlates in monkey premotor cortex
No full textCognitively advanced animals are able to dynamically interact with the environment. In this process, action selection could be strongly influenced by the confidence value assigned to single items in the stream of incoming sensory information.
A form of dynamic representation of the environment is the organization of learned items in hierarchically ordered series. In a 6-items transitive inference task, when the list A > B > C > D > E > F is finally created, the probability of choosing B in the pair BC is lower than for the pair BE suggesting that the confidence for the value of B is variable and related to the mental representation of all other elements presented/experienced together. This relationship between performance and symbol separation is also know as symbolic distance effect.
Previous work has focused on the contribution of sensory information to confidence. We explored how confidence on target value could influence action selection by measuring neuronal activity in the premotor cortex of 2 trained monkeys. We selected neurons with activity modulated by the direction of movement and we analyzed how directionality is influenced by the symbolic distance of items to compare. Our results show that directionality in premotor cortex increases with symbolic distance and uncertainty providing support to the idea that the motor system contributes to perceptual confidence
Effect of Motivation on Movement Control: Neural Correlates in Dorsal Premotor Cortex
No full textThe dorsal premotor cortex (PMd) is a brain area involved in the control of movement. An open question is how the motivation can modulate this function.
We trained a macaque monkey to a modified version of the countermanding task, in which Go trials (~65%) require to make a movement after a go signal, while Stop trials (~35%) require to inhibit the reactive movement after a stop signal.
In each trial, an initial cue (1000 msec delay) informed about the potential amount of reward that would have been delivered if a correct response would have been produced. The meaning of the cue for correct responses was different. In the Go+Stop- condition the cue indicated more reward for the Go trials and less reward for the Stop trials. The opposite was in the Go-Stop+ condition. The cue was not informative (neutral) for the GoStop condition.
We found that the monkey adapted his behavior to the cue value: faster reaction times in Go trials and higher error rate in Stop trials diminished from Go+Stop-, to GoStop and then to Go-Stop+ conditions. In PMd we found that 43/74 neurons recorded distinguished between conditions: some of them started to differentiate between conditions after 500msec from the cue, others close to the go signal. Seventeen/43 neurons were directly involved in movement control and showed different responses to the stop signal presentation depending on the cue presented.
These data suggest that in PMd motivational information is integrated into neural mechanism of movement control by a heterogeneous dynamic
Motor inhibition to dangerous objects: Electrophysiological evidence for task-dependent aversive affordances
Full text linkPrevious work suggests that perception of an object automatically facilitates actions related to object grasping and manipulation. Recently, the notion of automaticity has been challenged by behavioral studies suggesting that dangerous objects elicit aversive affordances that interfere with encoding of an object’s motor properties; however, related electrophysiological studies have provided little support for these claims. We sought EEG evidence that would support the operation of an inhibitory mechanism that interferes with the motor encoding of dangerous objects and we investigated whether such mechanism would be modulated by the perceived distance of an object and the goal of a given task. Electroencephalograms were recorded by 24 participants who passively perceived dangerous and neutral objects in their peripersonal, boundary or extrapersonal space and performed either a reachability judgment task or a categorization task. Our results showed that greater attention, reflected in the visual P1 potential, was drawn by dangerous and reachable objects. Crucially, a frontal N2 potential, associated with motor inhibition, was larger for dangerous objects only when participants performed a reachability judgment task. Furthermore, a larger parietal P3b potential for dangerous objects indicated the greater difficulty in linking a dangerous object to the appropriate response, especially when it was located in the participants’ extrapersonal space. Taken together, our results show that perception of dangerous objects elicits aversive affordances in a task-dependent way and provides evidence for the operation of a neural mechanism that does not code affordances of dangerous objects automatically, but rather on the basis of contextual information
The Neural Correlates of Action Representation in the Real World
Full text linkThis thesis is about action representations and their neural correlates. Action representations serve as internal models of our behaviour, constructed through dynamic interaction between body and environment, shaped by knowledge and experience. We rely on action representations in order to act in an everchanging environment. Considering that much of our real world behaviour involves dynamic movements with degrees of freedom that are not tolerated by traditional brain imaging techniques, we have long been constrained in examining how actions are represented in the brain. In this thesis, limitations of traditional brain imagining techniques are overcome by employing a novel mobile EEG approach, which allows the identification of the neural markers of the action representations underlying real world locomotor behaviour
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
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
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