On-line optical imaging of the human brain with 160-ms temporal resolution.

We have developed an instrument for non-invasive optical imaging of the human brain that produces on-line images with a temporal resolution of 160 ms. The imaged quantities are the temporal changes in cerebral oxy-hemoglobin and deoxy-hemoglobin concentrations. We report real-time videos of the arterial pulsation and motor activation recorded on a 4 x 9 cm 2 area of the cerebral cortex in a healthy human subject. This approach to optical brain imaging is a powerful tool for the investigation of the spatial and temporal features of the optical signals collected on the brain.