1,720,974 research outputs found
Behavioral and neurophysiological modulation of error-related processes
Full text linkThe term brain modulation refers to a wide range of interventions that allow modifying the central nervous system. The general purpose of this dissertation will regard the investigation and modulation of error-related processes through the use of behavioral interventions and noninvasive brain stimulation (NIBS). In order to accomplish this aim, three studies were conducted.
Study 1 investigated the motivation-cognition interaction. In particular, this study aimed to increase error awareness by using rewards in a group of healthy older adults, compared to younger adults. Results showed a reduction of error awareness when participants were rewarded, both older and younger adults. This detrimental effect of rewards suggests more attention in planning motivational interventions with the aim to modulate error awareness.
Study 2 aimed to investigate the neural bases of error awareness and modulate error awareness by using on-line transcranial magnetic stimulation (TMS). Results revealed an implication of the dorsolateral prefrontal cortex (DLPFC) in error awareness. However, this modulation was specifically induced by a single-pulse TMS paradigm, compared to a paired-pulse TMS paradigm that did not produce a modulation of the process. These results highlight how subtle variations of the TMS paradigm can differently affect error awareness.
Study 3 investigated the behavioral and neurophysiological modulation of error-related processes induced by a low-frequency repetitive TMS paradigm. Results showed a reduction of the error positivity (Pe), an electrophysiological component associated with error awareness, only when the left DLPFC was stimulated, compared to the homologous right DLPFC and the Vertex. This result contributes to provide new knowledge about error-related processes, in particular about the neural bases of the Pe.
Finally, a critical review of these studies will provide general insights for the design of future modulatory interventions
Repetitive TMS over the left dorsolateral prefrontal cortex modulates the error positivity: An ERP study
Full text linkError processing is a critical step towards an efficient adaptation of our behavior to achieve a goal. Little research has been devoted to investigate the contribution of the dorsolateral prefrontal cortex (DLPFC) in supporting error processing. In this study, the causal relationship of the DLPFC in error commission was examined by means of a repetitive transcranial magnetic stimulation protocol (rTMS). Specifically, the effects of an inhibitory protocol were assessed by examining the electroencephalographic signal recorded during the execution of a Go/No-Go task. To this aim, a group of 15 healthy young participants performed a three-session study. At each session, either the right DLPFC, the left DLPFC, or the Vertex (control site) were stimulated, for 20 min at 1 Hz. Immediately after the stimulation, participants performed the task. Although no behavioral effects of rTMS emerged, the analysis of event-related electric potentials (ERPs) revealed that the amplitude of a positive potential evoked by error commission, the error positivity (Pe), was reduced after the stimulation of the left DLPFC. On the contrary, the earlier error-related negativity component (ERN) was not affected. These results revealed that the left DLPFC intervenes at later stages of error-related processes. We could speculate that its role is specifically linked to error awareness
Intra-individual variability of error awareness and post-error slowing in three different age-groups
No full textState-dependent tDCS modulation of the somatomotor network: A MEG study
No full textObjective: Transcranial direct current stimulation (tDCS) is a non-invasive technique widely used to investigate brain excitability and activity. However, the variability in both brain and behavioral responses to tDCS limits its application for clinical purposes.This study aims to shed light on state-dependency, a phenomenon that contributes to the variability of tDCS.Methods: To this aim, we investigated changes in spectral activity and functional connectivity in somatomotor regions after Real and Sham tDCS using generalized additive mixed models (GAMMs), which allowed us to investigate how modulation depends on the initial state of the brain.Results: Results showed that changes in spectral activity, but not connectivity, in the somatomotor regions depend on the initial state of the brain, confirming state-dependent effects. Specifically, we found a non-linear interaction between stimulation conditions (Real vs Sham) and initial state: a reduction of alpha and beta power was observed only in participants that had higher alpha and beta power before Real tDCS.Conclusions: This study highlights the importance of considering state-dependency to tDCS and shows how it can be taken into account with appropriate statistical models.Significance: Our findings bear insight into tDCS mechanisms, potentially leading to discriminate between tDCS responders and non-responders. (C) 2022 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved
Novel insights into the relationship between cerebellum and dementia: A narrative review as a toolkit for clinicians
No full textThe role of the cerebellum in neurodegenerative disorders that target cognitive functions has been a subject of increasing interest over the past years. However, a review focused on making clinicians more aware of the role of the cerebellum in dementia is still missing. This narrative review explores the possible factors explaining the involvement of the cerebellum in different kinds of dementia by providing more insights on how this structure can be relevant in clinical practice. It emerged that, despite overlapping in specific areas, structural cerebellar alterations in dementia show a certain degree of disease-specificity. Furthermore, the relevance of cerebellar changes in dementia is corroborated by correlations observed between their topography and cognitive symptomatology, as well as by its previously ignored involvement of the cerebellum in early stages of dementia. Despite needing further investigations, these findings could become a useful diagnostic aid for clinicians that should not be overlooked, in particular for those individuals who do not show distinct and manifest brain or neuropsychological alterations, but that still make clinicians suspect the presence of a neurocognitive disease
Aperiodic component of EEG power spectrum and cognitive performance are modulated by education in aging
Full text linkRecent studies have shown a growing interest in the so-called "aperiodic" component of the EEG power spectrum, which describes the overall trend of the whole spectrum with a linear or exponential function. In the field of brain aging, this aperiodic component is associated both with age-related changes and performance on cognitive tasks. This study aims to elucidate the potential role of education in moderating the relationship between resting-state EEG features (including aperiodic component) and cognitive performance in aging. N = 179 healthy participants of the "Leipzig Study for Mind-Body-Emotion Interactions" (LEMON) dataset were divided into three groups based on age and education. Older adults exhibited lower exponent, offset (i.e. measures of aperiodic component), and Individual Alpha Peak Frequency (IAPF) as compared to younger adults. Moreover, visual attention and working memory were differently associated with the aperiodic component depending on education: in older adults with high education, higher exponent predicted slower processing speed and less working memory capacity, while an opposite trend was found in those with low education. While further investigation is needed, this study shows the potential modulatory role of education in the relationship between the aperiodic component of the EEG power spectrum and aging cognition
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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