Stimulation protocol
SimNibs
Stimulation was delivered (NeuroConn DCStimulator Plus; neuroCare Grouo GmbH, Munich, Germany) using two saline-soaked surface sponge electrodes over the left dlPFC (anode, centered over F3, 10–20 EEG system, size: 5 × 7 cmDemonstration of the electrode placement and simulation of electric field distribution of applied stimulation parameters on MNI head/brain with SimNibs (simnibs.org, Version 3)Both atDCS and sham tDCS started with a 10-s ramp on and ended with a 10-s ramp off. In atDCS, the stimulation started with the first experimental block and lasted until 20 min—through the first half of the experiment blocks, while the second half of the experiment was not stimulated (see Fig. Experimental design. Illustration of atDCS and sham tDCS, which were realized in two sessions, separated approximately by 7 days. (In the sham tDCS, the stimulation duration was 30 s, including 20 s of ramping