LOCALIZED NEAR-INFRARED SPECTROSCOPY AND FUNCTIONAL OPTICAL IMAGING OF BRAIN ACTIVITY

Changes in cerebral blood flow (CBF) and cerebral metabolic rates (CMR O2) have been used as indices for changes in neuronal activity, Near-i nfrared spectroscopy (NIRS) can also measure cerebral haemodynamics an d metabolic changes, enabling the possible use of multichannel recordi ng of NIRS for functional optical imaging of human brain activity. Spa tio-temporal variations of brain regions were demonstrated during vari ous mental tasks. Non-synchronous behaviour of cerebral haemodynamics during the neuronal activation was observed. Gender- and handedness-de pendent lateralization of the function between right and left hemisphe res was demonstrated by simultaneous measurement using two NIR instrum ents during the mirror-drawing task. A lack of interhemispheric integr ation was observed with schizophrenic patients. These observations sug gest an application for NIPS in psychiatric disease management, as an addition to clinical monitoring at the bedside. A time-resolved 64-cha nnel optical imaging system was constructed. This consisted of three p icosecond laser diodes and 64 channels of TAC and CFD systems. Image r econstruction for phantom model systems was performed. Time-resolved q uantitative optical imaging will become real in the very near future.