To visualize the optical properties in cerebral cortex of in vivo rat brain, we investigated a spectral refl ectance images estimated by the Wiener estimation method form a digital RGB camera. The reduced scattering coeffi cient and absorption coeffi cient were successfully estimated by the diffuse refl ectance spectroscopy with the Monte Carlo simulation for light transport. In order to confi rm the possibility of the method, we performed in vivo experiments for exposed brain of rats during cortical spreading depression. The sequential images of total hemoglobin indicated the hemodynamic change in cerebral cortex. On the other hand, increases in μ s’ was observed before the profound increase in total hemoglobin, which is indicative of changes in light scattering by tissue. The results indicate potential of the method to evaluate the pathophysiological conditions of in vivo brain.