Examinando por Autor "Fernández-del-Olmo, Miguel Á."

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Effects of high-definition transcranial direct current stimulation on conflict resolution: insights from behavioral, EEG and phenomenological measures
(Elsevier, 2024-10) Sanabria, Daniel; Holgado, Darías; Martínez-Pérez, Víctor; Martín-Arévalo, Elisa; Bekinschtein, Tristán A.; Fernández-del-Olmo, Miguel Á.; Luque-Casado, Antonio
The efficacy of non-invasive brain stimulation techniques in enhancing conflict resolution abilities remains a contentious issue in cognitive neuroscience. To contribute further to this topic, we employed a sham-controlled between-groups design to investigate the cognitive, phenomenological, and physiological effects of anodal and cathodal high-definition transcranial direct current stimulation (HD-tDCS) targeting the bilateral dorsolateral prefrontal cortex (DLPFC) during conflict resolution tasks. Sixty participants completed a 30-minute flanker task, a widely used measure of cognitive control and conflict processing. Electroencephalography (EEG) activity was recorded at four time points: at rest, prior to task commencement, during task execution before tDCS administration, during task execution after tDCS administration, and post-task rest. Additionally, a novel method called temporal experience tracing (TET) was employed to retrospectively evaluate participants' subjective experiences throughout the experimental procedure. TET involved participants reporting the intensity of predefined experiential dimensions along a temporal axis. Findings revealed no statistically significant differences between tDCS groups in reaction time, accuracy data, drift diffusion modeling, or EEG frequency power analyses. Analysis of TET data unveiled an anticipated temporal pattern across all subjective dimensions, e.g., an increase in mind-wandering over time. Notably, significant differences between tDCS groups emerged in the "fed-up" and "boredom" dimensions, indicating varied subjective experiences influenced by stimulation conditions. Furthermore, Lempel-Ziv analysis demonstrated that EEG complexity escalated from the pre-task to post-task periods to a greater extent in the cathodal and sham conditions compared to the anodal condition. In summary, this study provides valuable insights into the nuanced effects of tDCS during conflict resolution tasks. Notably, the employment of the novel TET methodology allowed for a comprehensive assessment of participants' subjective experiences throughout the experimental procedure. These findings contribute to advancing our understanding of the cognitive and phenomenological effects of tDCS and underscore the importance of integrating innovative methodologies in neurostimulation research.
The impact of prefrontal tDCS on conflict resolution and its phenomenological dynamics: a HD-tDCS/EEG randomized sham-controlled novel approach based on Drift Diffusion Modeling
(Elsevier, 2023-10) Martínez-Pérez, Víctor; Martín-Arévalo, Elisa; Fuentes, Luis; Fernández-del-Olmo, Miguel Á.; Sanabria, Daniel; Luque-Casado, Antonio
When humans are faced with conflict resolution tasks, performance is usually impaired. The effects of applying non-invasive brain stimulation techniques on conflict resolution performance is still an open question under debate. In this study we will address this issue by assessing the cognitive and physiological effects of applying anodal and cathodal high-definition transcranial direct current stimulation (HD-tDCS) over bilateral dorsolateral prefrontal cortex (DLPFC) on conflict resolution by using a 30-min flanker task. Moreover, the effects of the stimulation on phenomenological constructs such as mind-wandering, boredom, perceived cognitive effort and arousal over the course of the task will be addressed. In a pre-registered, randomized, sham-controlled, parallel study, we will assign participants to one of the three groups of stimulation: anodal, cathodal, and sham. A pre-post resting state EEG and the task-related oscillatory activity during the first and last 6-min temporal blocks of the task will be measured. Stimulation will be applied online from the second to the fourth block of trials (18 minutes). Right after, participants will be asked to report their temporal experience tracing (TET), a method that captures relevant aspects of their phenomenological experiences over a continuous period of time by drawing their headway in the task between two axes. Behavioral data will be analyzed by applying a drift diffusion modelling that enables statistical separation of different components of a speeded binary decision process. This novel approach will allow us to get a more thorough understanding of cognitive processes and electrophysiological mechanisms underlying the effects of cathodal and anodal stimulation on conflict resolution. As far as we know, this will be the most comprehensive piece of work within this research topic.