Scientists have made significant strides in the field of non-invasive brain imaging by developing a groundbreaking technique that involves shining light through the head, from one side to the other. This innovative approach aims to enhance our understanding of the human brain without the need for invasive procedures.
Currently, the most effective portable and low-cost method for monitoring brain activity is functional near-infrared spectroscopy (fNIRS). However, this technology has its limitations, as it can only penetrate a few centimeters into the brain. For deeper insights, larger and bulkier MRI machines are typically required. The new method developed by researchers at the University of Glasgow in Scotland addresses this challenge by expanding the sensitivity of fNIRS to allow light to pass through the various layers of bone, neurons, and tissue in the human skull.
To achieve this remarkable advancement, the researchers implemented several key modifications. They increased the strength of the near-infrared laser while ensuring that it remained within safe operational boundaries. Additionally, a more comprehensive light collection setup was established. Despite these enhancements, initial experiments revealed that only a small number of photons managed to travel from one side of the head to the other. Nonetheless, this breakthrough represents a significant step forward for portable imaging methods, offering crucial insights into brain activity without the need for surgical intervention.
The findings from this study indicate the potential to extend non-invasive light-based brain imaging technologies to the tomography of critical biomarkers deep within the adult human head. However, the researchers acknowledged several caveats. The new technique was only successful in one out of eight study participants—a man with fair skin and no hair. Furthermore, the method requires a specific setup and an extended scanning time of approximately 30 minutes.
Despite these limitations, the researchers sacrificed certain variables, such as speed, to demonstrate the feasibility of transmitting light through the human head using fNIRS, and they succeeded. Detailed 3D head scans were utilized to create computer models that predicted the movement of photons through the skull. The actual light collected closely matched these models, adding credibility to the results.
Interestingly, the research revealed that light did not scatter randomly as it passed through the head. Instead, it followed preferred pathways, particularly through areas that were more transparent, such as those containing cerebrospinal fluid. This newfound knowledge could enhance the targeting of brain scans in future applications. By varying the source positions on the head, researchers can selectively isolate and probe deeper regions of the brain.
The advantages of fNIRS lie in its relative affordability and compact nature. This technology has the potential to make brain scans for conditions such as strokes, brain injuries, and tumors more accessible to a broader population. As new imaging devices are developed, the insights gained from this research will be invaluable for creating techniques that delve deeper into the brain, even if it may take time before we can achieve practical light transmission through the entire head.
Brain scans hold immense value, contributing to our understanding of everything from adolescence in young individuals to disease treatment in later life stages. The potential of optical modalities for non-invasive imaging of the human brain is poised to bridge the gap between cost-effective portable devices like electroencephalography (EEG) and high-resolution, expensive instruments like functional magnetic resonance imaging (fMRI), as noted by the researchers.
