Forward Model of Rat Electroencephalogram: Comparative Study of Numerical Simulations With Measurements on Rat Head Phantoms

In the paper, we propose a procedure to be used for the validation of software for forward modeling of rat electroencephalogram with scalp potentials measured on rat head phantoms. Measurements are performed on a cuboidal phantom, a simplified shape of a rat brain, and an anatomically realistic, computed tomography (CT)-based phantom considering the brain and the skull. The physical phantoms are composed of an agar mixture to mimic the rat brain, excitation dipoles for modeling the neural activity of the brain, electrodes for monitoring the surface electric potential and a 3D printed skull. To ensure correct positions of dipoles and electrodes for numerical simulations, the phantoms are scanned by a computed tomography. After that, reconstructed 3D models are simulated in three EM solvers and results are compared with EEG measurements. Differences between simulations and measurements are further analyzed by parametric simulations and discussed. Obtained results provide the software validation method for rat brain forward modeling. Properly validated computation of electric potentials is essential for development of electrical brain stimulation protocols as well as in optimization of electrode placement.