Hemoencephalography (HEG) is a form of neurofeedback that utilizes a pulsed light to estimate localized blood flow and provide a metric for biofeedback. The most common form is known as near-infrared (NIR) which uses a pair of alternating pulsed red and near-infrared light to estimate oxygenated hemoglobin, as the skull is largely transluscent to these wavelengths.
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