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sam_power computes the Hilbert envelope of power for continuous data and outputs a 3D+time image. It does not compute event-related power (like sam_ers and sam_ersc or sam_4d and sam_4dc. sam_power is intended for use in connectivity studies of the correlation of the envelope of power among voxels — e.g., by using ICA or the AFNI function “Instacorr”.
sam_power applies the beamformer coefficients to the filtered MEG data (specified by ImageBand) to compute the estimated source timeseries. It then applies the Hibert transform to obtain the envelope of power. This is followed by a lowpass filter (specified by SmoothBand) and resampling at the interval specified by TimeStep. The smoothed, resampled Hilbert envelope of power is written out to each voxel.