[Research progress in the technique of integrating multiple imaging modalities in the functional brain imaging]

In the last few years, brain science has exhibited an explosive growth in hemodynamic/metabolic data on brain function. In particular, PET and functional MRI provide excellent spatial resolution, but their temporal resolutions are severely limited by relatively slow responses of brain metabolism. By contrast, EEG and MEG are able to track modulations of current source activity at millisecond time scales, but suffer from poor spatial resolution. Hence, high-resolution spatiotemporal imaging of brain activity requires integration of information from multiple signal modalities. In this paper we discuss what is known about the physical and physiological basis of the imaging signals, suggest various approaches that have been proposed for integrating information across multiple modalities, and briefly analyze the future directions and remaining challenges in the field of multi-modality integration.