INTRINSIC OPTICAL-CHANGES IN NEURONAL TISSUE - BASIC MECHANISMS

Associated with changes in the level of physiological activity in neur onal tissue are changes in the intrinsic optical properties of the tis sue. As a consequence, it is possible to optically monitor neuronal ac tivity without the use of dyes or other contrast-enhancing agents. Suc h optical techniques have been applied in the laboratory for more than 50 years. Recent developments in near-infrared spectroscopy and intra operative optical imaging have suggested a number of clinically import ant applications of this technology. This article provides an overview of what is known about the physiological correlates and underlying me chanisms associated with activity-evoked optical changes in neuronal t issue.