In this work, a new method for cortical potential imaging (CPI) is shown. The potential distribution measured on the scalp during standard EEG procedure is back-projected to the cortex surface using an electroquasistatic mechanism. The proposed method combines the information from MRI derived realistic head conductivity model with approximated boundary conditions (surface Laplacian) of the cortical normal currents, together with the finite element method (FEM). The back-projection CPI (BP-CPI) which gives a simple, fast, high-resolution and accurate CPI, solved in only one iteration. The BP-CPI was designed for easy integration with monitoring and stimulation tools for better understanding the underlying cortical activity. The analysis is backed by simulative validation results.