FMRI-MEG integrative neuroimaging in an apparent visual motion perception task

We have developed an fMRI-MEG integrative neuroimaging method that is capable of analyzing spatiotemporal multiple cortical activities. The method determines the center of gravity in each fMRI activated cluster as the location of the linear constraints. First, activated multiple clusters were determined by statistically analyzing fMRI data. Secondly, using the fMRI activated clusters as spatial constraints, the orientations of equivalent current dipoles (ECDs) placed at the center of gravity in each voxel of all activated clusters were estimated by a procedure maximizing inner product of lead field and measured field vectors. Thirdly, the activities of all ECDs were estimated, and dynamic activities of them were visualized. The linear constraints for the voxels in a cluster are defined to suppress the power from the source at the center of gravity of the other cluster. The spatial distributions and the time courses of activities for all ECDs were successfully reconstructed. We applied the newly developed method to data obtained during an apparent visual motion perception task and could confirm its availability. Although there were individual differences, the present fMRI-MEG integrative neuroimaging method successfully detected dynamic cortical activities in multiple visual areas, such as V1, V2, V5 and IPS.