Scientists tested a system that uses brief, patterned flashes of light to activate targeted groups of neurons in genetically engineered mice—cells modified to respond specifically to light. The animals quickly learned to interpret these light patterns as meaningful signals and used them to make decisions and complete tasks, even though none of their natural senses were involved.

Figure 1. Scientists Unlock a Novel Sense by Teaching the Brain to Read Light.

Researchers believe this technique has wide-reaching potential: it could provide sensory feedback for prosthetic limbs, introduce new forms of artificial input for future hearing or vision technologies, offer drug-free pain management, aid recovery after strokes or injuries, and enhance control of robotic or prosthetic devices. Figure 1 shows Scientists Unlock a Novel Sense by Teaching the Brain to Read Light.

Engineers demonstrated the technology by programming it to flash light patterns that mimicked the sequence of a Tetris game. These intricate bursts of light transmitted information straight into the brain, completely bypassing the body’s normal sensory pathways.

A New Approach to Creating and Exploring Brain Signals

“Our brains constantly translate electrical activity into experience, and this technology allows us to interface directly with that process,” said Northwestern neurobiologist Yevgenia Kozorovitskiy, who led the experimental research. “With this platform, we can generate entirely new signals and watch how the brain learns to use them. It moves us a step closer to restoring lost senses and offers a powerful tool for studying how perception works.”

Developing the device required reimagining how to deliver patterned stimulation in a system that is both minimally invasive and fully implantable, explained Northwestern bioelectronics pioneer John A. Rogers, who led the device development. By combining a soft, flexible array of hair-thin micro-LEDs with a wirelessly powered control module, the team built a system that can be programmed in real time while remaining fully beneath the skin—with no impact on the animals’ natural behavior. This marks a major leap toward brain-interface devices that avoid cumbersome wires or bulky external equipment. It has immediate value for neuroscience research and long-term promise for addressing neurological and sensory disorders.

Building on the Foundation of Optogenetics

This work builds on the team’s earlier breakthrough—a fully implantable, wireless, battery-free optogenetic device introduced in Nature Neuroscience in 2021. That earlier system used a single micro-LED to influence social behavior in mice, overcoming the movement-restricting fiber-optic cables of traditional optogenetics.

The new version is more powerful and versatile. Instead of controlling one small region, it features a programmable array of up to 64 micro-LEDs, each dynamically adjustable. This enables more sophisticated light sequences that resemble the distributed activity patterns associated with real sensory experiences. Because perception involves coordination across multiple brain regions, this multi-LED array produces more lifelike stimulation.

“In our first device, we used just one micro-LED,” said Wu. “Now we have 64, letting us design nearly limitless combinations of frequency, intensity, and timing.”

A Softer, Surface-Level Design

Despite added capability, the device remains compact—about the size of a postage stamp and thinner than a credit card. Unlike earlier probes that penetrated brain tissue, this version sits on the skull and delivers light through the bone.

Training the Brain to Decode Artificial Signals

For testing, mice with light-responsive cortical neurons learned to associate a specific pattern of stimulation with a reward. The implant delivered a coded light sequence across four cortical regions, and the mice learned to distinguish this “signal” from many other possible patterns. When they detected the right one, they went to the correct port to receive a reward.

“By choosing the correct port repeatedly, the animal showed it had received and understood the message,” Wu explained. “Since mice can’t tell us what they perceive, their behavior reveals what they’ve learned.”

Toward Advanced Artificial Perception

Having shown that the brain can interpret patterned light as meaningful information, the researchers plan to explore even more complex sequences. Future devices may include more LEDs, tighter spacing, wider cortical coverage, and varied wavelengths capable of reaching deeper brain areas.

Source: SciTECHDaily

Cite this article:

Priyadharshini S(2025), Researchers Train the Brain to Perceive Light in an Entirely New Way, AnaTechMaz, pp.435