Near Infrared Spectroscopy

One of the major technological breakthroughs in human neuroscience research has been the development of functional magnetic resonance imaging (fMRI). This technique, for the first time allowed us to measure changes in blood oxygen levels (and by extension brain activity) while subjects were performing a specific task. Over the years, this technique has been improved and refined especially in spatial, which can now be as small as 1 mm.

While structural MRI has also been developed for rats and mice, fMRI is technically very challenging, mainly because of the risk of movement artefact. fMRI requires subjects to be completely still, and thus animals have to be either sedated or anesthetised, which obviously precludes any behavioural studies. One potential alternative to fMRI is Near Infrared Spectroscopy (NIRS). NIRS is based on the principle that while most biological tissues are virtually transparent to infrared light, haemoglobin and oxygenated haemoglobin both absorb infrared light. Thus like fMRI, NIRS can be used to measure blood oxygen levels in the brain. Moreover, compared to fMRI, this can be done at a fraction of the co st.

In the project, we aim to develop a wireless NIRS system to measure brain blood oxygenation in freely moving animals.  This project is a collaboration with Professor Bor Shyh Lin from the National Chiao Tung University in Taiwan. Prof Lin is working a miniaturizing a prototype NIRS system that sends data via Bluetooth to a computer. Within our group, we will test the system in freely moving rats, which will help us to further refine the system. This project is supported by a Catalyst: Seeding grant.