Fig. 8.

(a). Power spectral density of raw source reconstructed time course for the HMM beamformer (green), stationary beamformer (red), and HMM beamformer followed by beta band bandpass filtering (black). Representative 2 s time segment of the raw source reconstructed time course (b), and the corresponding Hilbert envelope time course (c), for the stationary beamformer (red) and the HMM beamformer (blue), where the black dots indicate when there is a switch in HMM state. Note that there is no qualitative evidence of strong discontinuities or oscillatory components due to the fast HMM state switching. Results are shown for the left motor cortex (MNI coords: [36 − 18 52] mm) in the finger tapping MEG dataset.