Variable resolution electric-magnetic tomography

A nerv type of Distributed Im ene Solution (DIS) is proposed: Variable Resolution Electric and Magnetic Tomography (VARETA). This method is a weighted minimum norm solution in which a regularization parameter is used that varies spatially at each point of the solution grid. Usual DIS (including LORETA) are particular case of VARETA in which the regularization parameter is a constant. At points in which the regularization parameter is small the source is treated as concentrated. When the regularization parameter is large the source is estimated to be zero. Thus Vareta incorporates automatically both concentrated and distributed sources as well as dealing with the pruning of points at which there is no activity.