COMETS: A MATLAB toolbox for simulating local electric fields generated by transcranial direct current stimulation (tDCS)

Purpose Three-dimensional (3D) numerical computation of electric fields generated by transcranial direct current stimulation (tDCS) has widened our insight into the underlying mechanisms of current conduction, accelerated the development of novel electrode montages, and enabled more accurate field concentrations to targeted brain areas. However, there is no well-established field simulator specifically designed to analyze electric fields due to tDCS. Methods We developed a MATLAB-based toolbox, COMETS ( COM putation of E lectric field due to T ranscranial current Stimulation), for simulating local electric fields generated by tDCS. Since COMETS has a simple and interactive graphical user interface, users can readily simulate various electrode configurations, sizes, and orientations without coding any MATLAB scripts. COMETS evaluates 3D cortical current distributions based on the electrostatic finite element method (FEM). Results Although only a standard human head model is provided in the current version, users may import their own head model datasets for specific research. For advanced 3D visualization of the resultant cortical current distributions, output data can also be exported to readily accessible ASCII-format data files. The toolbox package is freely available at http://www.COMETStool.com for noncommercial and academic uses. Conclusions It is expected that our toolbox COMETS can contribute to popularizing the numerical analysis of cortical stimulation current in the field of noninvasive electrical brain stimulation.