ABSTRACT
This chapter introduces a non-invasive brain function measurement using light including NIRS at first. It discusses the techniques which enable non-invasive measurement of brain activity accompanied by high spatial and temporal resolution using near-infrared light or a static magnetic field. The development of non-invasive techniques to allow the measurement of brain activity is imperative for revealing how the human brain functions. Light is scattered and goes in various directions in biological tissue. The nature of the medium with respect to light can be characterized by absorption and scattering. The relationship between local neural activity and subsequent changes in cerebral blood flow is called neurovascular coupling. The measurement of fast intrinsic optical responses is a promising method that may provide a useful alternative to electrophysiological techniques for dynamic measurements of neural activation. Optical techniques offer a number of technical advantages; measurements are fast, cost-effective, and non-invasive, with high spatial and temporal resolution.
