Research Spotlight: Probe Smaller Than a Human Hair to Map the Brain

The Lundbeck Foundation is a research-focused foundation that is a major driver of neuroscience innovation. The Foundation, which is the largest shareholder of Lundbeck and owns 70 percent of the company, annually provides approximately $100 million in research grants, the majority going to brain research projects. We’re spotlighting innovative research funded by the Foundation and highlighting neuroscience pioneers who are working to advance understanding of the brain and brain diseases.

A notoriously difficult problem in neuroscience is the lack of direct access to the brain and neural activity. The ability to directly observe, examine and record brain activity could accelerate research and provide new insights into brain dysfunction. A Lundbeck Foundation-funded research project aims to solve this challenge once and for all with one of the world’s smallest optical-fiber probes. The research project is called Multi-BRAIN and is led by Christos Markos, an Associate Professor at the Department of Photonics Engineering at the Technical University of Denmark (DTU). The research aims to unravel the activities in the brain directly through extremely tiny fiber probes.

“The optical fiber will be the smallest fiber probe, that I know of, which can enter the brain to accelerate pre-clinical research. If it succeeds, we will obtain a new tool that can potentially diagnose, understand and help decipher several major neurodegenerative diseases,” says Christos Markos, who hopes the mini-probe would be applicable in future research areas looking at diseases such as Alzheimer’s and Parkinson’s disease.

The project aims to develop an optical fiber probe that can stimulate neurons in the brain while recording and imaging their activity instantaneously. That way the tool may depict neural activity of the brain while testing pre-clinical procedures.  

“The ability to deliver compounds to the brain through the probe using microfluidic channels, while mapping the activity, would be a valuable addition we aim to incorporate into this small probe. Together with the idea of using the probe to activate and record neurons, we would have a strong tool for future brain research,” says Christos Markos.

Optical fibers
The probe is expected to be even smaller than a human hair and will enter the brain through a micro hole in the skull. That way it will be able to enter the brain while doing minimal damage to the brain tissue. On average, a human hair measures around 100 micrometers. One micrometer is a millionth of a meter, meaning the probe would be 100 times smaller than a centimeter.

“The technology of optical fibers relies upon a thermal-drawing process. The materials that will end up as the final fiber are molten together in a furnace, after which it is stretched out to a very thin strand. It is this kind of operation that is also used for kilometers of optical fibers used for telecommunication,” explains Christos Markos.

“This has been my scientific vision for more than five years. The idea of combining multiple scientific disciplines with the new technological advances in optical fibers can hopefully take us forward in understanding and solving several neurodegenerative diseases,” says Christos Markos.

Learn more about the Lundbeck Foundation and grantees at 


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