Near-infrared spectroscopy (NIRS) is widely used in studies of brain activity. In this article I explain the principles
and theoretical limits of NIRS. I also discuss the need for the development of portable NIRS.
Near-infrared, spectroscopy, brain, hemoglobin, oxygenation
The Graduate School for the creation of new photonics industries, 1955-1 Kurematsu, Nishi-ku, Hamamatsu, Shizuoka, 431-1202, Japan