Brain computer interfaces (BCIs) are gaining popularity. A novel interface system that synchronizes the activity of hundreds of tiny brain sensors. BCI systems use implantable sensors to record electrical signals in the brain. Then use those signals to drive external devices such as robotic prosthetics or computers. These ingenious systems will play a major role in understanding how the brain functions in the future. BCIs may, thereby, help develop new medical therapies. They can play a potential role as assistive devices that may help people with spinal or brain injuries to move or communicate.
A team of researchers have taken the BCIs to the next level. Published in the journal Nature Electronics, their ingenious findings are going to play an important role in the field of medicine. At present BCIs use up to two sensors to obtain signals from a few hundred neurons. There is a demand for sensors which can collect signals from higher number of neurons. In this scientificbreakthrough the team has developed an ingenious BCI system. The novel system uses a coordinated network of microscale, wireless independent neural sensors. The size of about a grain of salt, these neural sensors can record and stimulate brain activity. Known as “neurograins”, the sensors independently obtain the electrical pulses produced by firing neurons and wirelessly transmit the signals to a central hub. The central hub in turn processes and coordinates the signals. According to the team, they could successfully use 50 autonomous “neurograins” to record neural activity in a rodent. The outcome of this novel system is remarkable. It may help record neuronal signals in great details. This will pave way to a better understanding of the activities of the brain. Thus, therapies for people with spinal or brain injuries can be developed in the future using this ingenious system.
This study aimed at collecting neuronal signals from a live brain (rodent was used as the animal model). Experts from multiple disciplines were needed to deal with the challenges of developing, designing and operating the BCI system. Till date BCIs are mainly based on monolithic microelectrode devices (somewhat like a little beds of needles). There are disadvantages of a BCI system based on monolithic microelectrode devices. The architecture of monolithic microelectrode array hinders flexibility in scaling to a large number of nodes and electrode placement, specifically in non-contiguous locations.
This team has converted the monolithic device into tiny sensors that can be spread across the cerebral cortex. The team designed and developed tiny silicon “neurograin” chips which would replace the complex electronics presently being used to detect, amplify and transmit neural signals. The body-external communications hub, a thin patch (size of a thumb print) that attaches to the scalp outside the skull, was developed to receives signals from those tiny chips. Functioning like a miniature cellular phone tower, the body-external communications hub employs a network protocol to coordinate the signals from the neurograins. It even supplies power wirelessly to the neurograins. Each neurograin has its own network address and has been designed to operate using a minimal amount of electricity.
There were multiple hurdles in developing this new BCI system. The system required both wireless networking and power transfer, simultaneously, at the mega-bit-per-second rate. All of this had to be under power constraints and extremely tight silicon area. The research team has also gone on to test the novel BCL system’s ability to stimulate the brain as well as record from it. The body-external communications hub has been used to stimulate the brain with tiny electrical pulses that can activate neural activity. In the future this feature of the ingenious system could be used to restore the brain function lost due to injury or illness. According to the team the ingenious BCI system developed by them can support up to 770 neurograins. In the future, the team hopes to scale up the BCI enabling it to support several thousands of neurograins which will help gain a better understanding of the brain’s functioning.
Brain computer interfaces (BCIs) are gaining attention as life changing supportive devices for people with devastating brain or spinal injuries. This team has developed ingenious wirelessly, networked and powered, electronic microchips. This novel systemcan autonomously perform neural sensing and electrical micro-stimulation. Future work is still needed for this new BCI system. This system will provide deeper understanding of the brain’s activity. It will also revolutionize therapies available for extreme brain injuries.
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