Functional Near Infrared Spectroscopy

Functional Near-Infrared Spectroscopy (fNIRS) is an innovative neuroimaging technique that offers a non-invasive method to monitor brain activity. Utilising near-infrared light, fNIRS measures changes in blood oxygenation levels within the brain, providing insights into neural function and connectivity.

The principle behind fNIRS is based on the differential absorption of near-infrared light by oxygenated and deoxygenated haemoglobin. When neural activity occurs in a specific brain region, the demand for oxygen increases, leading to a localised increase in blood flow. This haemodynamic response alters the balance between oxygenated and deoxygenated haemoglobin, which fNIRS detects through light absorption patterns.

One of the significant advantages of fNIRS is its portability and ease of use compared to other neuroimaging techniques like Functional Magnetic Resonance Imaging (fMRI). fNIRS equipment is typically more compact and less expensive, making it accessible for a variety of settings, including clinical environments, research laboratories, and even schools. Moreover, the technique’s non-invasive nature means it is well-tolerated by a wide range of participants, including infants and patients with neurodevelopmental disorders.

fNIRS has found applications across diverse fields. Cognitive neuroscience is employed to investigate brain functions such as language processing, memory, and executive functions. Its real-time monitoring of cortical activation makes it invaluable for studying dynamic cognitive processes. In clinical settings, fNIRS is used to assess brain function in patients with conditions such as stroke, traumatic brain injury, and epilepsy. The technique also holds promise in the emerging field of brain-computer interfaces, where it can facilitate communication and control in individuals with severe motor impairments.

Even though it has many advantages, fNIRS is not without limitations. The technique is primarily limited to monitoring cortical activity, as near-infrared light cannot penetrate deeply into the brain. Consequently, it provides limited information about subcortical structures. Additionally, fNIRS’s spatial resolution is lower than fMRI’s, which can be a drawback in studies requiring detailed anatomical precision.

Therefore, Functional Near-Infrared Spectroscopy is a versatile and promising tool in the area of neuroimaging. Its non-invasive nature, portability, and broad applicability make it a valuable asset for both research and clinical practice. As technology advances, fNIRS will likely play an increasingly important role in understanding brain function and dysfunction.