Improvement on Attention Networks Among Military Personnel: The Right IFG and tDCS Matter

Abstract

Attention is crucial for military personnel to recover from mental dysfunction and maintain superior cognitive abilities. Transcranial electrical stimulation (tES) is a promising training method for enhancing attention; however, the optimal parameters for tES interventions remain unclear. This study aims to identify the most responsive cortical area and the most effective tES type for attention enhancement. In Experiment 1, 62 healthy male soldiers were examined to determine the most effective stimulation target for attention improvement after 4 (cathodal electrodes) × 1 (anodal electrodes) high-definition transcranial direct current stimulation (tDCS) on the right inferior frontal gyrus (IFG) or the left dorsolateral prefrontal cortex (DLPFC). Experiment 2, involving 75 participants, focused on modulating the previously identified appropriate cortex using both high-definition transcranial alternating current stimulation (tACS) and tDCS to ascertain the most effective tES method based on behavioral and neural activity changes. Both experiments were double-blind and sham-controlled. Executive control of attention networks was significantly improved after tDCS modulation of both the right IFG and the left DLPFC. Notably, only the modulation of the right IFG effectively decreased the Stroop effect. While both tACS and tDCS on the right IFG induced lower neural activity related to the Stroop effect, only tDCS significantly reduced the behavioral performance of the Stroop effect. Consequently, the right IFG emerges as a key targeted cortex for tES modulation in enhancing attention, with tDCS proving more effective than tACS in regulating the right IFG to improve executive control. These findings lay the groundwork for applying tES interventions in the training of attention abilities among military personnel.