Most of current BCI systems use one or two sensors to sample up to a few hundred neurons, but neuroscientists are interested in systems that are able to gather data from much larger groups of brain cells. A team of researchers has taken a key step toward a next generation of BCI system. It employs a coordinated network of independent, wireless microscale neural sensors, each about the size of a grain of salt, to record and stimulate brain activity. The sensors, called as "neurograins," independently record the electrical pulses made by firing neurons and send the signals wirelessly to a central hub, which coordinates and processes the signals.
Here some key features of recently developed, next generation BCI-
Modified monolithic design:
Arto Nurmikko, a professor in Brown's School of Engineering and the study's senior author said that, "Up to now, most BCIs have been monolithic devices means 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 and can receive signals from neurons more accurately.
New external communication hub:
Researchers developed a newly designed body-external communications hub for a next generation BCI. This hub receives signals from tiny chips and function as a receiver of neural signals.
Jihun Lee, a postdoctoral researcher at Brown and the study's lead author said, "This work was a true multidisciplinary challenge. We had to bring together expertise in electromagnetics, radio frequency communication, circuit design, fabrication and neuroscience to design and operate the neurograin system."
Device design:
The next generation BCI device is a thin patch, about the size of a thumb print, that attaches to the scalp outside the skull. It works like a miniature cellular phone tower, employing a network protocol to coordinate the signals from the neurograins, each of which has its own network address. The patch also supplies power wirelessly to the neurograins, which are designed to operate using a minimal amount of electricity.
Testing trials on animals:
The team placed 48 neurograins on the animal's cerebral cortex, the outer layer of the brain, and successfully recorded characteristic neural signals associated with spontaneous brain activity. The team also tested the devices' ability to stimulate the brain as well as record from it. Stimulation is done with tiny electrical pulses that can activate neural activity. The stimulation is driven by the same hub that coordinates neural recording and could one day restore brain function lost to illness or injury, researchers hope.
The size of the animal's brain limited the team to 48 neurograins for this study, but the data suggest that the current configuration of the system could support up to 770. Ultimately, the team envisions scaling up to many thousands of neurograins, which would provide a currently unattainable picture of brain activity.
There's much more work to be done to make that complete system a reality, but researchers said this study represents a key step in that direction.
"Our hope is that we can ultimately develop a system that provides new scientific insights into the brain and new therapies that can help people affected by devastating injuries," Nurmikko said.
Here is the Image of tiny sensors of Next generation BCI.
References:
- Materials provided by Brown University.
- Jihun Lee, Vincent Leung, Ah-Hyoung Lee, Jiannan Huang, Peter Asbeck, Patrick P. Mercier, Stephen Shellhammer, Lawrence Larson, Farah Laiwalla, Arto Nurmikko. Neural recording and stimulation using wireless networks of microimplants. Nature Electronics, 2021; DOI: 10.1038/s41928-021-00631-8
