A computational model of regional personalized electrodes to select transcranial electric stimulation target.

Introduction: Recently we developed a new procedure to personal- ize the electrode to selectively stimulate specific cortical regions by transcranial electric stimulations (tES).This study aims to assess by computational approach the distribution of the intra-cerebral elec- tric field induced by tES through the personalized in comparison with a non-personalized electrode in human models. Methods: We used two realistic human models and 40 tissue con- ductivities.We targeted bilateral primary motor (M1) and somatosensory cortex (S1) alternatively with the personalized and non-personalized electrode, with the reference on the occipital area. We estimated the distribution of the electric field across the brain structures. Results: The personalized electrode was able to modulate more deeply and strongly the area of the central sulcus than the non- personalized one. This trend was more evident in the regions along the central sulcus more far away from Cz, where the two electrodes are less overlapped and for both targets (M1 and S1). Moreover, the personalized electrode used to target S1 more selectively modulated the postcentral gyrus, whereas the personalized electrode used to target M1 broadened its effects over both the pre and postcentral gyrus. Discussions: This work strengthens the notion that tES can be focused by properly shaping and positioning the stimulating elec- trodes according to the target regions. doi:10.1016/j.clinph.2015.11.419