Localization of class-related mu-rhythm desynchronization in motor imagery based Brain-Computer Interface sessions

We localize the sources of class-dependent eventrelated desynchronisation (ERD) of the mu-rhythm related to different types of motor imagery in Brain-Computer Interfacing (BCI) sessions. Our approach is based on localization of singletrial Fourier coefficients using sparse basis field expansions (SFLEX). The analysis reveals focal sources in the sensorimotor cortices, a finding which can be regarded as a proof for the expected neurophysiological origin of the BCI control signal. As a technical contribution, we extend S-FLEX to the multiple measurement case in a way that the activity of different frequency bins within the mu-band is coherently localized.