A single session of bi-hemispheric tDCS over the left dorsolateral prefrontal cortex and right orbitofrontal cortex does not modulate executive function performance in healthy adults

Resumo original em inglês

O que aconteceu

Executive functions (EFs) are top-down cognitive processes essential for adaptive behavior and goal-directed actions, supported by prefrontal cortical networks. The left dorsolateral prefrontal cortex (L-DLPFC) and right orbitofrontal cortex (R-OFC) are key regions implicated in cognitive control and flexible decision-making, respectively. Transcranial direct current stimulation (tDCS) offers a non-invasive means to modulate cortical excitability and investigate causal contributions of these regions to EFs. However, findings on the efficacy of tDCS in enhancing EFs remain inconsistent, particularly for tasks that engage multiple executive components simultaneously. Twenty-one healthy male participants completed a randomized, sham-controlled, double-blind, crossover study. Each participant underwent two sessions (active tDCS and sham) in counterbalanced order. tDCS stimulation consisted of 2.0 mA anodal tDCS over F3 (L-DLPFC) and cathodal tDCS over Fp2 (R-OFC) for 30 min. EFs were assessed using the Flanker/Reverse Flanker fish task, which engages inhibitory control, cognitive flexibility, and working memory. Also, adverse effects and blinding efficacy were assessed post-stimulation. Computational electric-field modeling revealed peak stimulation under the R-OFC, suggesting diffuse prefrontal modulation rather than focal targeting fo the L-DLPFC. Equivalence testing further indicated that the interaction effects were statistically equivalent within predefined bounds of practical relevance. Response time improved significantly from pre- to post-test across both conditions, but this effect was not modulated by tDCS. Adverse effects were mild and infrequent, with no significant differences between tDCS and sham conditions. In conclusion, anodal stimulation of L-DLPFC combined with cathodal stimulation of R-OFC did not produce meaningful behavioral modulation of EFs performance under the present experimental conditions.

Resumo publicado sob licença CC BY. A tradução para o português ainda não chegou a este estudo.