text: More detailed computation simulations can be carried out accounting for not cellular models, but taking into consideration the functional syncytium and enabling the cells to mutually interact, the so-called electrotonic coupling.
  In case of tissue simulation or in wider cases, such as in whole organ simulations, all the cellular models are note applicable anymore, and several corrections have to be made. Firstly, the governing equations can not be just ordinary differential equations, but a system of partial differential equations has to be accounted for. A suitable choice may be the monodomain model:
  <math>\triangledown \cdot(D\nabla V)=(C_m\frac{\partial V}{\partial t} + I_{ion}(V,u)) 
  where  is the effective conductivity tensor, is the capacitance of the cellular membrane,  the transmembrane ionic current,  and  are the domain of interest and its boundary, respectively, with  the outward boundary of .