Reconstructing MEG sources with unknown correlations
Maneesh Sahani, W. M. Keck, Srikantan S. Nagarajan · 2004
Existing source location and recovery algorithms used in magnetoen-cephalographic imaging generally assume that the source activity at dif-ferent brain locations is independent or that the correlation structure is known. However, electrophysiological recordings of local field poten-tials show strong correlations in aggregate activity over significant dis-tances. Indeed, it seems very likely that stimulus-evoked activity would follow strongly correlated time-courses in different brain areas. Here, we present, and validate through simulations, a new approach to source reconstruction in which the correlation between sources is modelled and estimated explicitly by variational Bayesian methods, facilitating accu-rate recovery of source locations and the time-courses of their activation. 1