Researchers at Cornell University have developed a neural implant smaller than a grain of salt that uses laser powered wireless technology to monitor brain activity for over a year, marking a major advance in neuroengineering and implantable device design.
The device, called a microscale optoelectronic tetherless electrode, or MOTE, measures roughly 300 microns long and 70 microns wide, yet can transmit electrical signals from inside the brain without wires or bulky hardware. It was co led by Professor Alyosha Molnar and Assistant Professor Sunwoo Lee, who powered the implant using red and infrared laser beams that safely penetrate brain tissue. Data is sent back through faint pulses of infrared light.
“As far as we know, this is the smallest neural implant that can measure electrical activity in the brain and report it wirelessly,” said Molnar. “By using pulse position modulation, similar to satellite optical communication, we can use very little power and still get reliable data.”
The researchers first tested the MOTE in cell cultures before implanting it into the barrel cortex of mice, a region that processes sensory input. Over a year, it recorded neuronal spikes and network activity while the animals remained healthy. One added benefit is potential MRI compatibility, since its aluminium gallium arsenide semiconductor could allow safe imaging.
Compared to earlier wireless brain implants, the MOTE stands out for its size, laser based power system, and long recording duration. Other devices, such as Northwestern University’s dopamine tracking implant, worked for shorter periods and were far larger. Meanwhile, human speech decoding implants require invasive infrastructure.
The Cornell device’s potential spans both medicine and neuroscience. For patients with epilepsy, Parkinson’s or Alzheimer’s, continuous monitoring could improve diagnosis and treatment. Its minimal invasiveness also reduces surgical risks, while long term recordings could reveal new insights into learning, sleep and neurodegeneration. Future versions might even close the loop by detecting biomarkers and triggering stimulation or drug release automatically.
As Molnar noted, “By using very little power to communicate and still get the data out optically, we open the door to monitoring brain behaviour over periods we couldn’t imagine before.”
You can read the complete research here.