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Background: Transcranial Magnetic Stimulation (TMS) is a widely used tool to explore the causal role of focal brain regions in cognitive processing. TMS effects over attentional processes are consistent and replicable, while at the same time subjected to individual variability. This individual variability needs to be understood to better comprehend TMS effects, and most importantly, its clinical applications., Objective: This study aimed to explore the role of white matter variability in TMS neuromodulatory effects on behavior in healthy participants (N = 50)., Methods: Participants completed an attentional task in which orienting and alerting cues preceded near-threshold targets. Continuous Theta Burst Stimulation (cTBS) was applied over the left frontal eye field (FEF) or an active vertex condition. White matter was explored with diffusion-weighted imaging tractography and Tract-Based Spatial Statistics (TBSS)., Results: Behaviorally, TMS over the left FEF slowed down reaction times (especially in the alerting task), impaired accuracy in the objective task, and reduced the proportion of seen targets (as compared to the vertex condition). Attentional effects increased, overall, when TMS was applied to the left FEF as compared to the vertex condition. Correlations between white matter and TMS effects showed i) reduced TMS effects associated with the microstructural properties of long-range white matter pathways such as the superior longitudinal fasciculus (SLF), and interhemispheric fibers of the corpus callosum (CC), and ii) increased TMS effects in participants with high integrity of the CC connecting the stimulated region with the opposite hemisphere. Additionally, variability in attentional effects was also related to white matter, showing iii) increased alerting effects in participants with low integrity of association, commissural, and projection fibers, and iv) increased orienting effects in participants with high integrity of the right SLF III., Conclusion: All these observations highlight the importance of taking into account individual variability in white matter for the understanding of cognitive processing and brain neuromodulation effects., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: Impaired self-awareness (SA) after acquired brain injury (ABI) has traditionally been linked to deficits in executive functions. However, conflicting findings about this relationship have been reported in the literature. This inconsistency is probably due to the multicomponent nature of both constructs, as not all aspects of executive functions may be equally relevant to all components of self-awareness. This study explored whether offline SA (i.e. metacognitive knowledge) and online SA (i.e. error detection) relate to a less studied executive component, conflict monitoring/resolution., Method: Twenty-six patients with ABI performed the Three-Conflict Cognitive Control Task (3CCT), an experimental task that allowed to measure the ability to monitor and solve three different types of conflicts (Distractors-filtering, Spatial Stroop and Simon). Measures of SA were collected: offline SA was based on self-informant discrepancy about patient's everyday functional difficulties, and online SA was based on error detection abilities during a performance-based naturalistic task (The Breakfast Conflict Task)., Results: After controlling for global cognition, the conflict monitoring measure of 3CCT demonstarted incremental validity in predicting offline and online SA measured in naturalistic tasks., Conclusions: Conflict monitoring/resolution seems to be an important component of SA. This finding contributes to further understand the relationship between executive functions and SA. In addition, conflict monitoring/resolution is an executive component that should be considered when designing assessment and intervention strategies to deal with ISA.

Social and nonsocial directional stimuli (such as gaze and arrows, respectively) share their ability to trigger attentional processes, although the issue of whether social stimuli generate other additional (and unique) attentional effects is still under debate. In this study, we used the spatial interference paradigm to explore, using functional magnetic resonance imaging, shared and dissociable brain activations produced by gaze and arrows. Results showed a common set of regions (right parieto-temporo-occipital) similarly involved in conflict resolution for gaze and arrows stimuli, which showed stronger co-activation for incongruent than congruent trials. The frontal eye field showed stronger functional connectivity with occipital regions for congruent as compared with incongruent trials, and this effect was enhanced for gaze as compared with arrow stimuli in the right hemisphere. Moreover, spatial interference produced by incongruent (as compared with congruent) arrows was associated with increased functional coupling between the right frontal eye field and a set of regions in the left hemisphere. This result was not observed for incongruent (as compared with congruent) gaze stimuli. The right frontal eye field also showed greater coupling with left temporo-occipital regions for those conditions in which larger conflict was observed (arrow incongruent vs. gaze incongruent trials, and gaze congruent vs. arrow congruent trials). These findings support the view that social and nonsocial stimuli share some attentional mechanisms, while at the same time highlighting other differential effects. Highlights Attentional orienting triggered by social (gaze) and nonsocial (arrow) cues is comparable. When social and nonsocial stimuli are used as targets, qualitatively different behavioral effects are observed. This study explores the neural bases of shared and dissociable neural mechanisms for social and nonsocial stimuli. Shared mechanisms were found in the functional coupling between right parieto-temporo-occipital regions. Dissociable mechanisms were found in the functional coupling between right frontal eye field and ipsilateral and contralateral occipito-temporal regions., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.)

Arrows and gaze stimuli lead to opposite spatial congruency effects. While standard congruency effects are observed for arrows (faster responses for congruent conditions), responses are faster when eye-gaze stimuli are presented on the opposite side of the gazed-at location (incongruent trials), leading to a reversed congruency effect (RCE). Here, we explored the effects of implicit vs. explicit processing of arrows and eye-gaze direction. Participants were required to identify the direction (explicit task) or the colour (implicit task) of left or right looking/pointing gaze or arrows, presented to either the left or right of the fixation point. When participants responded to the direction of stimuli, standard congruency effects for arrows and RCE for eye-gaze stimuli were observed. However, when participants responded to the colour of stimuli, no congruency effects were observed. These results suggest that it is necessary to explicitly pay attention to the direction of eye-gaze and arrows for the congruency effect to occur. The same pattern of data was observed when participants responded either manually or verbally, demonstrating that manual motor components are not responsible for the results observed. These findings are not consistent with some hypotheses previously proposed to explain the RCE observed with eye-gaze stimuli and, therefore, call for an alternative plausible hypothesis., (© 2022. The Author(s).)

Subtle to no attentional differences have been broadly observed when using gaze and arrows as orienting cues. However, recent studies have found opposite effects when they are used as targets in spatial interference tasks, with arrows eliciting faster responses when their position is congruent with the indicated direction and gaze producing faster responses in incongruent conditions. In two preregistered experiments aimed at exploring the mechanisms supporting these findings, we examined whether the congruency sequence effects (CSE) elicited by gaze and arrows generalized from one stimulus to another, using an intrablock design where the type of stimuli was manipulated on a trial-by-trial basis. Typical CSE were observed for arrows, with a decrease of congruency effects after incongruent trials, and reversed CSE for gaze, with an increased inversion of congruency effects after incongruent trials. Both patterns occurred independently of the preceding type of target, showing that congruency effects can decrease after positive outcomes (e.g., arrow trials following an incongruent gaze trial), and generalized across different nonsocial and social stimuli as shown in a third experiment. These results are consistent with the coexistence of a shared spatial interference component between gaze and arrow trials, potentially responsible for the CSE obtained in switching target trials, and an additional social dimension, exclusively engaged in gaze trials. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

It has been proposed that attention triggered by eye-gaze may represent a unique attentional process, different from that triggered by non-social stimuli such as arrows. To investigate this issue, in the present study we compared the temporal dynamics of the conflict processing triggered by eye-gaze and arrow stimuli. We investigated the electrophysiological activity during a task in which participants were required to identify the direction of laterally presented eye-gaze or arrow targets. Opposite behavioural effects were observed: while arrows produced the typical effect, with faster responses when they were congruent with their position, eye-gaze targets produced a reversed effect with faster responses when they were incongruent. Event-related potentials showed common and dissociable congruency modulation: whereas eye-gaze and arrows showed similar effects on earlier ERP components (P1 and N1), they led to opposite effects in later components such as N2 and P3. This represents the first electrophysiological demonstration of both early shared and later dissociable congruency effects for eye-gaze and arrow stimuli., (Copyright © 2019 Elsevier Ltd. All rights reserved.)