A team of American scientists has developed a silicon brain-computer interface (BCI) as thin as a hair, which can be implanted in the brain and is capable of transferring data at high speeds. The device, its creators claim, will transform human-computer interaction.

The BCI can be used to treat neurological conditions such as epilepsy, spinal cord injuries, ALS, strokes, and blindness. It will help control seizures and restore motor, speech, and visual functions thanks to a 'minimally invasive' yet high-performance design.

Ultra-thin silicon chip for wireless brain connection

The interface uses a silicon chip to establish a high-bandwidth wireless connection between the brain and an external computer.

The platform is called the Biological Cortical Interface System (BISC) and has been developed by researchers from Columbia University, New York-Presbyterian Hospital, Stanford University, and the University of Pennsylvania.

The BCI includes a single implantable chip that functions as a portable 'repeater station,' and the custom software necessary for the system to work, the authors explain in a article in Nature Electronics.

“Most implantable systems are built around a container of electronic components that occupies a huge volume of space inside the body,” says Ken Shepard, an engineer at Columbia University and one of the lead authors of the paper.

“Our implant is a single integrated circuit chip so thin that it can slip into the space between the brain and the skull, resting on the brain like a piece of damp tissue paper,” he explains.

Revolutionary potential for neurological disorders

The fact that BISC is made up of a single chip “paves the way for adaptive neuroprostheses and brain-AI interfaces to treat many neuropsychiatric disorders, such as epilepsy,” says Andrea Tolias,from Stanford University and co-author of the study.

“This high-resolution, high-throughput device has the potential to revolutionize the treatment of neurological conditions, from epilepsy to paralysis,” says Brett Youngerman of Columbia University and a clinical collaborator on the project.

CMOS Technology: Smaller, Safer, and More Powerful

BCIs are tools that, through sensors implanted in the brain, capture the electrical signals that neurons use to transfer information throughout the brain and convert them into actions.

The most advanced ones used today in the medical field are made with microelectronic components, such as amplifiers, data converters, radio transmitters, and power management circuits.

But to fit all these elements, a large electronic container must be surgically implanted in the body; by removing part of the skull or placing the device in the chest—and connecting the wires to the brain.

BISC is different: the entire implant, which occupies less than one-thousandth the size of a conventional device, is a single complementary metal-oxide-semiconductor (CMOS) integrated circuit chip only 50 micrometers thick, about the thickness of a human hair.

With a total volume of approximately 3 mm³, the flexible chip conforms to the surface of the brain, yet integrates 65,536 electrodes, 1,024 simultaneous recording channels, and 16,384 stimulation channels.

Minimally invasive implant with WiFi connectivity

The implanted chip includes a radio transceiver (a device that includes a transmitter and a receiver), a wireless power circuit, digital control, power management, data conversion, and the analog circuitry necessary to support the recording and stimulation interfaces.

The The repeater station is itself an 802.11 WiFi device, which in practice forms a repeated wireless network connection from any computer to the brain. “By integrating everything onto a single piece of silicon, we have demonstrated how brain interfaces can be smaller, safer, and much more powerful,” says Shepard. To test the surgical methods and safely implant the device, the authors used preclinical models and demonstrated its quality and stability. Studies are now underway in human patients. “The implants can be inserted through a minimally invasive incision in the skull and slid directly onto the surface of the brain in the subdural space.Its paper-thin shape and the absence of electrodes penetrating the brain or wires connecting the implant to the skull minimize tissue reactivity and signal degradation over time,” Youngerman comments. To accelerate its application to clinical practice, the Columbia and Stanford teams launched Kampto Neurotech, which is developing commercial versions of the chip for preclinical research applications and raising funds to advance the system toward human use. (EFE, Columbia University, Nature Electronics)