New Breakthrough Allows Light to Traverse the Human Brain
WafricNews - June 20, 2025
In a stunning leap for neuroscience, researchers in Glasgow have achieved what once sounded like science fiction: they’ve detected light that travels through the entire human head — from one side to the other.
This breakthrough, led by Professor Daniele Faccio and his team at the University of Glasgow, pushes the limits of how we see inside the brain, offering a powerful new approach to non-invasive brain imaging that could someday rival MRI and CT scans.
What’s the Big Deal?
For years, scientists have used a method called functional near-infrared spectroscopy (fNIRS) to study the brain. It’s affordable, portable, and uses harmless light to measure brain activity, especially how blood oxygen levels change in outer brain regions.
But here’s the problem: fNIRS could only see a few centimeters deep. The skull and brain tissue scatter and absorb light so intensely, scientists believed it was physically impossible to detect any light that could pass all the way through.
Well, that theory just got turned on its head.
Lighting Up the Brain Like Never Before
The Glasgow researchers managed to detect photons — tiny packets of light — that traveled over 15 centimeters, cutting straight through the entire width of an adult human head. That means light passed through skin, skull, brain, and out the other side, in what’s now called diametrical photon transmission.
It’s the first time such a feat has been accomplished in an adult human. Until now, the idea of collecting light after it passed through that much biological tissue seemed like a fantasy. Some calculations even predicted the light would be reduced by a factor of 10⁵³ — an unimaginably tiny signal.
But using extremely sensitive detectors and advanced imaging methods, the Glasgow team proved otherwise.
“This work explores the limits of photon transport in the brain,” said Prof. Faccio, the lead author of the study published in Neurophotonics.
Why It Matters — Especially for Africa and the Global South
Most countries in Africa lack access to advanced, bulky imaging machines like MRIs or PET scans. The idea that a small, portable, low-cost system could one day see deep into the brain is a game-changer — not just for labs in Glasgow or New York, but for clinics in Lagos, Nairobi, Accra, and beyond.
Imagine diagnosing neurological conditions in rural health centers, monitoring brain injuries at football fields, or even helping detect early signs of mental illness — all using a simple light-based device. This could become a democratizing technology for global health.
Why Was This Thought Impossible?
Near-infrared light is known for scattering when it hits biological tissue. The more layers it goes through, the weaker and more scrambled it becomes. Traditional fNIRS systems only shine light into the scalp and pick up the scattered reflections nearby.
But collecting light on the opposite side of the head — after it passes through the entire brain — was considered not just difficult, but futile. Now that we know it can be done, researchers around the world are likely to revisit their assumptions.
What Comes Next?
The breakthrough doesn’t mean your doctor will be using head-scanning flashlights, but it opens new research avenues. The next steps include:
- Building better detectors to capture more deep-traveling photons.
- Developing imaging algorithms to reconstruct clearer pictures of the brain.
- Creating portable devices that can be tested in clinical settings.
If perfected, this technique could revolutionize the way we study and treat brain-related conditions — and make brain imaging accessible to parts of the world previously left behind.
By WafricNews Desk.
By WafricNews Desk.
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