New Fiber-Optic Device Revolutionizes Neural Activity Control

A groundbreaking advancement in neurotechnology has emerged from researchers at Washington University in St. Louis. They have developed a novel fiber-optic device called PRIME (Panoramically Reconfigurable IlluMinativE) fiber, which can manipulate neural activity across thousands of neurons simultaneously. This innovative device holds the potential to transform brain research, similar to how fiber-optic technology has revolutionized telecommunications.

The team, comprising experts from the McKelvey School of Engineering and WashU Medicine, has addressed a significant limitation in existing optical fibers. Traditional fibers can only deliver light to a single destination, which restricts researchers’ ability to explore complex brain circuits. To overcome this, the PRIME fiber can direct light in multiple directions, akin to a controllable disco ball illuminating different areas of the brain.

Innovative Techniques Enhance Brain Research

Led by Song Hu, a professor of biomedical engineering, and in collaboration with Adam Kepecs, a professor of neuroscience and psychiatry, the research team employed ultrafast-laser 3D microfabrication. This technique allowed them to inscribe thousands of light emitters into a fiber no thicker than a human hair. The result is a device capable of delivering multi-site, reconfigurable optical stimulation, enabling unprecedented scale in deep-brain stimulation.

In their proof-of-concept studies, the team analyzed the effects of PRIME in freely behaving animal models. Shuo Yang, a postdoctoral researcher and the first author of the study, highlighted the significance of their work: “We’re carving very small light emitters into very small pieces, meaning tiny mirrors that are 1/100th the size of a human hair.” This advancement facilitates precise control over neural activity, allowing researchers to explore how different brain circuits interact and give rise to specific behaviors.

During experiments, Keran Yang, a graduate student and co-first author, utilized the PRIME fiber to manipulate neuron activity within the superior colliculus, a critical area for sensorimotor transformation. By systematically inducing freezing or escape behaviors based on varying light patterns, the team demonstrated the device’s versatility. “This kind of tool lets us ask questions that were impossible before,” Yang explained.

Future Directions and Potential Applications

Looking ahead, the researchers aim to enhance the PRIME fiber into a bidirectional interface that combines optogenetics with photometry. This upgrade would enable simultaneous stimulation and recording of brain activity, providing deeper insights into neural functions. “This device significantly expands what’s possible in experimentally linking distributed neural activity to perception and action,” Kepecs noted.

The ultimate goal of the research team is to develop a wireless and wearable version of the PRIME fiber. “The less cumbersome the tool, the more natural the data they can get from freely behaving subjects that are not bogged down in wires,” Hu stated. With ongoing innovations, the potential applications of this technology could lead to breakthroughs in understanding brain functions and treating neurological disorders.

The findings from this research, published in Nature Neuroscience, represent not only a significant neurotechnology innovation but also a fabrication breakthrough in the field. As researchers continue to explore the applications of this technology, it may pave the way for new methods of studying and interpreting brain activity, ultimately enhancing our understanding of human behavior and cognition.

For more detailed insights, refer to the study: Shuo Yang et al, “Laser-engineered PRIME fiber for panoramic reconfigurable control of neural activity,” Nature Neuroscience (2025). DOI: 10.1038/s41593-025-02106-x.