Optimization of electrical stimulation parameters based on the primary motor cortex

Transcranial electrical stimulation refers to the transmission of weak electrical currents to the brain through scalp electrodes to induce neuromodulatory effects. Current usually passes through two large electrodes, generating a diffusion electric field. In this article, we propose a new paradigm where multiple small electrodes with independent current control are systematically optimized to generate targeted and effective stimuli under safety constraints. We used finite element method combined with a model based on human head magnetic resonance imaging to develop a linear system that correlates the applied scalp current with the generated electric field. Then apply optimization techniques to derive yield increasing parameters that maximize intensity or focus at the target location. The results indicate that the optimal electrode structure is closely related to the required electric field orientation and optimization criteria. The two optimization methods used have achieved good results.