Researchers have made a groundbreaking discovery in the field of brain imaging by detecting light that has traveled through an entire adult human head. For years, near-infrared light has been used to study the brain noninvasively through a technique called fNIRS (functional near-infrared spectroscopy), which measures light absorption by blood in the brain to determine activity.

While fNIRS is valued for its portability and affordability, it has limitations in reaching deep brain regions. Typically, light only penetrates about 4 centimeters into the brain, restricting access to critical areas involved in functions like memory and emotion.

However, a recent study conducted by researchers at the University of Glasgow has shown that it is possible to measure light passing through an entire human head. By using powerful lasers and sensitive detectors, the team was able to capture photons traveling from one side of the head to the other, across its widest point.

Through detailed computer simulations, the researchers confirmed that the detected photons had indeed traversed the entire head, following specific paths guided by regions of the brain with lower scattering. This breakthrough opens up new possibilities for developing optical devices that can reach deeper brain areas than current technologies allow.

While the current method is not yet practical for everyday use and has limitations in terms of data collection time and participant characteristics, this discovery paves the way for future advancements in deep brain imaging. With further development, this approach could lead to more accessible and portable tools for diagnosing and monitoring conditions like strokes, brain injuries, or tumors.