Inverse source problems in electro- and magneto- encephalography
Résumé
Electro- and Magneto- encephalography (EEG and MEG) are measuring non-invasively the post-
synaptic brain electrical activity. At each time instant, EEG and MEG provide a few hundreds of
measurements at the scalp (or near) level, and these measurements can be obtained at about a
millisecond time resolution. In the frequency domain of interest for brain signals, the electromagnetic
propagation over the head is governed by the quasi-static approximation. The inverse problem of source
localisation seeks to identify the cortical electrical sources from the measurements. As the cortex is a
very convoluted surface, it is usually modeled with several thousand variables, which make the source
localisation an ill-posed problem. We will explore several strategies to solve this inverse problem with
different strategies to regularize this ill-posed problem.