A system and a method for optimizing the configuration of multisite transcranial current stimulation, including providing an electric field characteristic target map on the brain's cortex, the target map including multiple cortical targets, the multiple cortical targets are localized and/or continuously varying and spatially extended, providing a weight map on the cortical surface prioritizing the important of areas in the target map for the purposes of optimization; and calculating, based on the target and weight maps, optimal currents and optimal locations for a plurality of electrodes intended for providing transcranial current stimulation to globally stimulate at once the multiple cortical targets with excitatory, inhibitory or neutral stimulation.