Near-Infrared Spectroscopy (NIRS)
Near-Infrared Spectroscopy (NIRS) is a non-invasive neuroimaging technique which uses light to monitor cerebral blood flow (CBF) in the cerebral cortex.
How does it do this? Essentially, the haemoglobin protein which transports oxygen around the body absorbs a different amount of light depending on whether it has an oxygen molecule attached to it or not. NIRS emits these 2 wavelengths of light, via a headband, through the intact skull, and the scattering, absorption and returned light indicates how much oxygenated, de-oxygenated and total haemoglobin is present in the micro-vessels of the cortex. This tells us how demanding and active the corresponding cortical regions are.
The non-intrusive systems mean that participants can engage with other activities (e.g. completing cognitive tasks) whilst CBF is monitored; this can be for discrete points during a study or in its entirity.
We have 2 NIRS systems within the BPNRC and the type utilized depends on individual study requirements:
Continuous wave NIRS (CW NIRS)
We've been measuring CBF with this system for almost 8 years. The CW NIRS allows us to measure the acute; e.g. within a maximum 2-3 hr window, changes in CBF in response to nutritional interventions and we have validated this system with compounds ranging from resveratrol, caffeine and fish oils. Please see these articles within the relevant pages of the publications area.
Frequency domain 'quantitative' NIRS (qNIRS)
The qNIRS opens up a broader range of research possibilities as its different transmission of light allows it to quantify the precise, as opposed to change, levels of oxygenated, de-oxygenated and total haemoglobin. This means that CBF can be measured over longer periods of time, in several participants within 1 session and across time periods (e.g. after a 3 month supplementation period) as recording can be ceased and recommenced whenever necessary.
The BPNRC also has links to local hospitals where functional magnetic resonance imaging (fMRI) is available to utilize for research purposes. Northumbria university also houses an electroencephalogram (EEG) system for research use. If you would like to find out more about these, or the NIRS technique, then please contact us.