Figure 1.

Cross‐talk functions (CTFs) for two different spatial filters aimed at extracting signals from anterior temporal lobe (ATL) while suppressing signals from inferior frontal gyrus (IFG). a) CTF for a classical minimum norm estimator (i.e. using the distributed source constraint) created for a target source (blue dot) in ATL. The CTF has largest amplitudes in ATL as desired. However, it also shows leakage from more distant locations, such as IFG. The area with largest leakage is indicated by a cloud of white dots. b) CTF for a novel estimator, derived by combining the distributed source constraint of a) with a discrete source constraint for IFG. The estimator was designed to optimally project on signals from the target location (blue dot), to suppress leakage from the IFG region (white dots), and to minimize leakage from all other brain areas. This had the intended effect that leakage from inferior frontal areas is reduced. Both images are presented with the same color scale.