Brain Stimulation for Mental Control

Military personnel need good self-regulation capacity to maintain adequate operational performance in situations of threat and prevent the risk on stress-related mental-health problems. Self-regulation skills could be temporarily facilitated by applying transcranial direct current stimulation (tDCS) to the DLPFC, probably through enhancing DLPFC-dependent executive functions such as working memory and inhibitory control. Yet, the potential longer-lasting benefits for self-regulation capacity under threat of a tDCS intervention have not yet been studied, and the neural underpinnings of these effects remain insufficiently understood.

The goal of this study is to investigate if a 3-session tDCS intervention targeting the DLPFC combined with working memory training improves regulation of reactions to threat. Second, we aim to verify if this intervention improves executive functioning in threat contexts, and to explore tDCS-induced modulations in neural activity linked to cognitive regulation and emotion.

This study is carried out among healthy Dutch military personnel.

A combined tDCS-working memory intervention strengthens self-regulation under threat via effects on DLPFC-linked neural activity

T0. Baseline measures of (i) reactions to threat of shock, (ii) inhibitory control, (iii) EEG.
T1-T3. tDCS sessions with measures of (i) working memory training performance and (ii) emotional state and tDCS side effects
T4. Post-intervention measures of (i) reactions to threat of shock, (ii) inhibitory control, (iii) working memory, (iv) EEG.

A tDCS intervention with an active tDCS group and a placebo group (sham tDCS), consisting of 3 repeated sessions targeting the DLPFC. TDCS is applied with an intensity of 2.0 mA over a 3x3 cm anode (on 10/20 EEG location F4) and 5x7 cm cathode (behind Cz) for 20 minutes, and is combined with a working memory (N-Back) training in a threat context.