FIGURE 2.

The electrode placement used in the individualized and non-individualized HD θ-tACS protocols. (Top) The individualized placement of electrodes for HD θ-tACS of the ACC targeted through the mPFC-ACC was selected on the basis of a reciprocity-optimized selection of current injection electrodes. Six anode-cathodes (red electrodes) and 10 cathode-anodes (blue electrodes) are shown. Note that to select the optimal electrode arrangement and current injection electrode, the individualized flux pattern with the highest specificity of current flow for a given target region (mPFC-ACC) on the cortical surface model was used. This is an example montage. (Bottom) Non-individualized placement of electrodes in the FCz and Pz areas (Vosskuhl et al., 2015; Fusco et al., 2018) adapted for the HCGSN 100 using the 10-channel mount with five anode-cathodes (red electrodes) in the FCz area and five cathode-anodes (blue electrodes) in the Pz area for a MFC and medial parietal cortex electrode layout. (Left) anterior view without marking the current density; (middle left) sagittal view; (middle right) anterior view; and (right) view from above, with cortex coloring representing the calculated current density on the cortical surface from 0.0 μA/mm² (black) to 1.0 μA/mm² (yellow).