Researchers at Brown University have developed wireless micro-implants that can function as a network of neural sensors and stimulators in the brain. The research team has dubbed their creation “neurograins,” which are intended to be implanted in the brain in large numbers. When inside, they can transmit data to an external communication hub, in the form of a patch attached to the scalp. The researchers hope that the neurograins will be able to record brain activity from a large number of neurons in the brain, allowing for advanced functionality when using brain-computer interfaces.
Brain-computer interfaces hold enormous promise as life-changing technologies for people with a variety of conditions. However, the technique is still in its infancy, and designing sensors that can effectively and safely monitor brain activity is a work in progress. Part of the issue is the complexity of the brain, and capturing this using a single sensor or affixing enough sensors in place is difficult. These researchers turned to miniaturization as a way to create a multitude of tiny sensors that can measure brain activity in numerous locations, all at once.
“One of the big challenges in the field of brain-computer interfaces is engineering ways of probing as many points in the brain as possible,” said Arto Nurmikko, a researcher involved in the study, in a Brown University announcement. “Up to now, most brain-computer interfaces have been monolithic devices – a bit like little beds of needles. Our team’s idea was to break up that monolith into tiny sensors that could be distributed across the cerebral cortex. That’s what we’ve been able to demonstrate here.”
The neurograins are tiny silicon chips about the size of a grain of salt. Getting them to this size was a challenge, requiring multiple iterations of computer-aided design. The neurograins transmit data to a thumbprint-sized patch affixed to the skull and they also are powered wirelessly by the patch. The patch acts as a communication hub, coordinating the signals from each neurograin.
“This work was a true multidisciplinary challenge,” said Jihun Lee, another researcher involved in the study. “We had to bring together expertise in electromagnetics, radio frequency communication, circuit design, fabrication and neuroscience to design and operate the neurograin system.”
“It was a challenging endeavor, as the system demands simultaneous wireless power transfer and networking at the mega-bit-per-second rate, and this has to be accomplished under extremely tight silicon area and power constraints,” said Vincent Leung, another researcher involved in the study. “Our team pushed the envelope for distributed neural implants.”
So far, the researchers have tested the neurograins in rodents, and placed a total of 48 on the cerebral cortex of each animal. They successfully recorded neural data. Strikingly, the neurograins can also provide neural stimulation, which could come in handy for modifying or restoring brain function in disease.
Study in Nature Electronics: Neural recording and stimulation using wireless networks of microimplants
Via: Brown University