Figure 1.

Spatiotemporal imaging of brain activity. The linear estimation approach for combining electromagnetic measurements with anatomical MRI and fMRI information is illustrated schematically. The inverse operator (W) is computed from anatomical information in the forward solution (A), fMRI information in the estimated source covariance matrix (R), and the sensor noise covariance matrix (C) from the MEG measurements. Applying the inverse operator to the MEG measurements [x(t)] yields movies of estimated cortical source activation over time [ŝ(t)]. The movies depict spatiotemporal estimates of the orchestration of cortical activation during a given task or behavior.