Integrating white matter anisotropy and structural connectivity for enhanced electric field precision in tDCS: a computational study

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique with promising application in the treatment of neurological and psychiatric disorders. However, its efficacy is hindered by inter-subject variability in aftereffects, mainly due to anatomical differences across subjects which are not considered during protocol design. Among these, structural connectivity plays a crucial role but remains underexplored in tDCS research. This study advances tDCS modelling by integrating white matter anisotropy into finite element method (FEM) simulations to assess how structural connectivity variations influence electric field (EF) distribution. By combining advanced computational approaches, we explore the relationship between EF strength and cortical connectivity, offering new insights into the subject-specific effects of tDCS. Incorporating white matter anisotropy altered EF distribution in the most connected regions to the anodal stimulation site, affecting its intensity, direction, and spread. Preliminary findings also suggest a positive and significant (p<0.05) correlation between EF focality and the strength of connectivity between cortical areas P2 and C2.