In a major step forward for neurobiology and bioelectronics, scientists at Northwestern University have created a wireless device that uses light to transmit information directly into the brain. The technology bypasses traditional sensory routes in the body and instead delivers signals straight to neurons.
The device is soft and flexible, fitting beneath the scalp while resting on the skull. From this position, it sends carefully controlled light patterns through the bone to activate specific groups of neurons across the cortex.
Light-Based Brain Signals in Animal Models
During testing, researchers used tiny, precisely timed bursts of light to stimulate targeted populations of neurons deep in the brains of mouse models. (These neurons are genetically modified to respond to light.) The mice quickly learned to interpret certain patterns as meaningful cues. Even without sound, sight or touch, the animals used the incoming information to make decisions and complete behavioral tasks accurately.
This technology could one day support a wide range of medical applications. Potential uses include providing sensory feedback for prosthetic limbs, delivering artificial inputs for future hearing or vision prostheses, controlling robotic limbs, improving rehabilitation after injury or stroke, and modifying pain perception without medications.
The work will appear Monday (Dec. 8) in Nature Neuroscience.
Creating New Brain Signals With Micro-LED Technology
"Our brains are constantly turning electrical activity into experiences, and this technology gives us a way to tap into that process directly," said Northwestern neurobiologist Yevgenia Kozorovitskiy, who led the experimental portion of the study. "This platform lets us create entirely new signals and see how the brain learns to use them. It brings us just a little bit closer to restoring lost senses after injuries or disease while offering a window into the basic principles that allow us to perceive the world."
John A. Rogers, a leading figure in bioelectronics and head of the technology development, said, "Developing this device required rethinking how to deliver patterned stimulation to the brain in a format that is both minimally invasive and fully implantable. By integrating a soft, conformable array of micro-LEDs -- each as small as a single strand of human hair -- with a wirelessly powered control module, we created a system that can be programmed in real time while remaining completely beneath the skin, without any measurable effect on natural behaviors of the animals. It represents a significant step forward in building devices that can interface with the brain without the need for burdensome wires or bulky external hardware. It's valuable both in the immediate term for basic neuroscience research and in the longer term for addressing health challenges in humans."
Kozorovitskiy is the Irving M. Klotz Professor of Neurobiology in Northwestern's Weinberg College of Arts and Sciences and a member of the Chemistry of Life Processes Institute. Rogers holds appointments in materials science and engineering, biomedical engineering and neurological surgery, and directs the Querrey Simpson Institute for Bioelectronics. The study's first author is postdoctoral researcher Mingzheng Wu.
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