ABSTRACT

Brain imaging makes it possible to associate neural activity of specific regions with a variety of physiological reactions of the organism. This chapter describes the physical and chemical bases, equipment, and principles of analysis of the intrinsic and voltage-sensitive dye optical imaging techniques. From a physiological point of view, the brain optical imaging methods can be classified into two categories: use of external fluorescence probes and use of intrinsic signals. Intrinsic optical signals (IOS) reflect metabolic activities, mainly oxygenation and deoxygenation, rather than neural spikes, but brain metabolism is directly associated with neural activity. Conventional IOS imaging approach has been used for functional brain mapping, and in studies of hemodynamics. Cerebral blood flow imaging during neurosurgery is necessary to perform vascular reconstruction. Intrinsic signal can be recorded by optical coherence tomography, a method based on low-coherence interferometry for performing high-spatial-resolution three dimensional optical imaging.