Spatial and temporal analysis of human motor activity using noninvasive optical topography

To noninvasively observe the spatiotemporal hemodynamic changes in the cortex that are associated with human cortical activity, we have recently proposed a novel cortical imaging method: noninvasive optical topography (OT). Using OT, which is based on spectroscopic reflection measurement of near-infrared light, we can visualize the changes in the oxygenation states of the cortex. By simulating regional absorption changes in a highly scattering medium using Monte Carlo method, we have determined that linear-signal processing can be used for OT. Furthermore, we have developed a 12-channel OT system and measured the hemodynamic changes around the central sulcus induced by finger movement. The changes caused by contralateral (right) finger movement were found to be significantly different than those due to ipsilateral (left) finger movement.