  The electroencephalography (EEG) forward problem, the computation of the
electric potential generated by a known electric current source configuration
in the brain, is a key step of EEG source analysis. In this problem, it is
often desired to model the anisotropic conductivity profiles of the skull and
of the white matter. These profiles, however, cannot be handled by standard
surface integral formulations and the use of volume finite elements is
required. Leveraging on the representation theorem using an anisotropic
fundamental solution, this paper proposes a modified symmetric formulation for
solving the EEG forward problem by a surface integral equation which can take
into account anisotropic conductivity profiles. A set of numerical results is
presented to corroborate theoretical treatments and to show the impact of the
proposed approach on both canonical and real case scenarios.
