Neurofeedback is a non-invasive method of direct brain function training.  It is also a type of biofeedback and is therefore, also called EEG Biofeedback.  It uses the electrodes (which act like tiny microphones) placed on the client's scalp to record and amplify the EEG, or brainwaves and control auditory, visual, and/or tactile feedback which allows learning to take place.  This operant learning initiates self-regulation and enhances relaxation, both necessary components of good brain function.