There are two main processes governing the ionic transport, i.e., diffusion—the particle motion caused by a gradient of concentration, and migration—motion of ions caused by a gradient of electrical potential. These two processes are referred to as electrodiffusion. Electrodiffusion of electrolytes serves as a mean for communication in the nervous system. It can directly affect the excitatory transmission in the synaptic cleft. Electrodiffusion maintains the local ions concentration in brain extracellular spaces at heathy levels but may be also involved in the propagation of epileptic seizures during pathological conditions. The accurate interpretation of physiological observations requires better understanding of the underlying electrodiffusion phenomena.The description of electrodiffusion is very often performed using the Nernst–Planck–Poisson (NPP) model. It has been acknowledged that the spatiotemporal dynamics of the ion concentrations in thin dendrites and dendritic spines of nerve cells follow the Nernst–Planck equation, and sub-membrane currents in neuronal membrane have already been successfully described using the NPP model.