“…To obtain asymptotic two-compartment models, we rely on a methodology based on classical scaled asymptotic expansions for thin structures (see [8,10,30]) and on an appropriate scaling of tangential and normal diffusion inside the myelin layer. This methodology has been extensively used to model thin coatings (see, e.g., [6,15] and references therein), rough boundaries (see, e.g., [1,19] and references therein) and imperfectly conducting obstacles (see, e.g., [16,17] and references therein).…”