The aim of this modeling study was to compare the focality (spatial extent) of induced cortical electric fields between conventional big pad tDCS and 4 X 1 ring electrode configurations. The head model was created at 1 mm X 1 mm X 1mm resolution.

- Peak induced cortical electric field under rectangular pad configuration was matched to that of 4 X 1 ring.
- The 4 X 1 ring led to significant increases in focality.
- Superficial cortical regions can be selectively targeted using a 4 X 1 system.
- Results can be translated to other waveforms (ECT,tACS,etc.)
The typical workflow involved segmentation from MRI scans, creation of finite element mesh and the eventual computation to solve for cortical induced electric fields.
