Near-Infrared Spectroscopy (NIRS) measures the hemodynamic changes following focal neuronal activity in the brain non-invasively. NIRS affords imaging of neocortical functions in a mobile, unobtrusive, and economical way, promising a high impact on future BCI applications. In this session we will introduce the principles of NIRS, i.e. the biological and physical background of the measurement, its instrumentation, and some recent applications in the field of BCI. In the experimental session we will explain the principles of a NIRS scanner and demonstrate its use and the preparation of a typical experimental setup. We will perform a physiological experiment of measuring the hemodynamic changes caused by executed and imaginary hand-gripping. The experimental results will then be analyzed using methods commonly applied to NIRS signals