OpenMEEG
OpenMEEG, now developed by the Athena project (INRIA Sophia Antipolis), is dedicated essentially to the resolution of the forward MEG (magneto-encephalography) and EEG (electroencephalography) problems. For this purpose, it uses a finite surface element method (BEM) that involves at the same time surface potentials and normal currents, which yields symmetrical matrices unlike classical approaches. This approach yields more precise results as well.
Though developed essentially for problems related to brain, OpenMEEG can also be used in other contexts such as electrocardiography, nerve simulation or electrical propagation in the cochlea.
OpenMEEG starts from a geometric-physical description of the head as nested surfaces in the form of meshes (interfaces between head tissues) and of conductivities of the surface delimited tissues. Then, with a description of EEG and/or MEG capture devices, it yields a leadfield, i.e., the transfer matrix modelizing the linear relation from sources to capture devices.
OpenMEEG is written entirely in C++, but is usable from Matlab or Python. It is used/integrated in a few software suites for analysis of signals in the brain, such as Brainstorm, Fieldtrip or SPM, ...