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Near Infra-Red Spectroscopy (NIRS)

NIRS is a method of recording changes in blood oxygen levels. In terms of the brain, it has been dubbed DIY-fMRI, in that like fMRI, it also measures changes in oxygenated and de-oxygenated haemoglobin (although by very different means).

To explain briefly, when an area of the brain is active, it uses oxygen to fuel this activity.

This is immediately followed by an increase in blood flow to that area, carrying fresh oxygen in the form of oxygenated haemoglobin. NIRS works by shining near infrared light into tissue and measuring the amount that is reflected back.

Changes in the concentration of oxygenated and de-oxygenated haemoglobin affect this reflection. NIRS records these changes and in so doing provides an indirect measure of cortical activity. The department has two 24-channels Artinis Oxymon III near infrared systems capable of being configured into one 48-channels system when required.