“Classical” least-squares minimum norm estimation (MNE) was introduced to MEG analysis by Hämäläinen and Ilmoniemi (1984). However, this method has the undesirable property that maxima of inverse solutions are biased towards the sensors (e.g. Fuchs et al., 1999; Lin et al., 2006). Several different approaches have been suggested to alleviate this problem
((https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3018574/)).