Fig. 2
Behavioral task, EEG and stimulation montage, hardware setup, and experimental overview. (a) The CTT behavioral task where the objective was to maintain the moving circle (~10 pixels) near the center of the middle annulus (~20 pixels) over the course of the experiment (70 mins). The ball was endowed with inherent motion, and oscillatory and dampening forces. Note, only the white ball and gray annulus were visible to participants, in the panel additional rings and distances are for illustrative purposes. (b) EEG locations (light blue) interleaved with stimulation sites for frontal (orange), motor (purple), and parietal (magenta) stimulation. For each stimulation montage, center electrodes are indicted by a star and surrounding electrodes by circles. Note, by design some electrode locations may serve as a center electrode for one montage and outer electrodes for another montage. (c) MRI-derived 3D head model with the stimulation locations placed on the scalp to visualize electrode placement. (d) Data acquisition and stimulation hardware setup in relation to participants’ input and output. (e) Experiment 1 and (g) Experiment 2 block design as programed to be executed within the hardware and software setup in panel (d). Experiments were divided into stimulation off blocks (Stim Off) without tES and stimulation enabled blocks (Stim Enabled) within which the selected tES stimulation condition was applied 4 times. (f) Experiment 1 and (h) Experiment 2 detailed block design with corresponding EEG triggers (dashed vertical line) and trigger codes. Note that the block design is not drawn to scale. Simultaneous EEG and Physio (EEG, ECG, and EOG; teal); and Behavior (CTT, red) were acquired with concurrent Stimulation (gold). Note, EEG and Physio acquisition started several seconds before any trigger delivery; and (e,f) are designed to illustrate the experimental design as programmed to be executed.
