Big Improvements To Brain-Computer Interface

Big Improvements to Brain-Computer Interface

When people suffer spinal cord injuries and lose mobility in their limbs, it’s a neural signal processing problem. The brain can still send clear electrical impulses and the limbs can still receive them, but the signal gets lost in the damaged spinal cord.

The Center for Sensorimotor Neural Engineering (CSNE)—a collaboration of San Diego State University with the University of Washington (UW) and the Massachusetts Institute of Technology (MIT)—is working on an implantable brain chip that can record neural electrical signals and transmit them to receivers in the limb, bypassing the damage and restoring movement. Recently, these researchers described in a study published in the journal Nature Scientific Reports a critical improvement to the technology that could make it more durable, last longer in the body and transmit clearer, stronger signals.

The technology, known as a brain-computer interface, records and transmits signals through electrodes, which are tiny pieces of material that read signals from brain chemicals known as neurotransmitters. By recording brain signals at the moment a person intends to make some movement, the interface learns the relevant electrical signal pattern and can transmit that pattern to the limb’s nerves, or even to a prosthetic limb, restoring mobility and motor function.

The current state-of-the-art material for electrodes in these devices is thin-film platinum. The problem is that these electrodes can fracture and fall apart over time, said one of the study’s lead investigators, Sam Kassegne, deputy director for the CSNE at SDSU and a professor in the mechanical engineering department.

Kassegne and colleagues developed electrodes made out of glassy carbon, a form of carbon. This material is about 10 times smoother than granular thin-film platinum, meaning it corrodes less easily under electrical stimulation and lasts much longer than platinum or other metal electrodes.

“Glassy carbon is much more promising for reading signals directly from neurotransmitters,” Kassegne said. “You get about twice as much signal-to-noise. It’s a much clearer signal and easier to interpret.”

The glassy carbon electrodes are fabricated here on campus. The process involves patterning a liquid polymer into the correct shape, then heating it to 1000 degrees Celsius, causing it become glassy and electrically conductive. Once the electrodes are cooked and cooled, they are incorporated into chips that read and transmit signals from the brain and to the nerves.

Researchers in Kassegne’s lab are using these new and improved brain-computer interfaces to record neural signals both along the brain’s cortical surface and from inside the brain at the same time.

“If you record from deeper in the brain, you can record from single neurons,” said Elisa Castagnola, one of the researchers. “On the surface, you can record from clusters. This combination gives you a better understanding of the complex nature of brain signaling.”

A doctoral graduate student in Kassegne’s lab, Mieko Hirabayashi, is exploring a slightly different application of this technology. She’s working with rats to find out whether precisely calibrated electrical stimulation can cause new neural growth within the spinal cord. The hope is that this stimulation could encourage new neural cells to grow and replace damaged spinal cord tissue in humans. The new glassy carbon electrodes will allow her to stimulate, read the electrical signals of and detect the presence of neurotransmitters in the spinal cord better than ever before.

Ad Astra, John Glenn (1921-2016)

An astronaut.

A pilot.

A husband.

A father.

A United States Senator.

An American hero.

An original.

John Glenn (1921-2016) was all those things and more. When he rocketed into space on Feb. 20, 1962, to become the first American to orbit Earth, the flight set the nation on course to meet ever-more ambitious goals.

The life and career of Senator Glenn eclipses those of many. In spite of his accomplishments, he was a humble and gracious man (and 4-term U.S. senator).

During Glenn’s first flight, a scheduled 30-minute test to determine whether Glenn could fly the capsule manually became a matter of life and death when the automatic system malfunctioned after the first orbit.

“I went to manual control and continued in that mode during the second and third orbits, and during re-entry,” Glenn recalled later. “The malfunction just forced me to prove very rapidly what had been planned over a longer period of time.” Another problem seemed even more serious – telemetry indicated the spacecraft’s heat shield was loose. It seemed possible that Glenn and the spacecraft would be incinerated on re-entry. Glenn left the retrorocket pack in place to steady the heat shield during re-entry. “It made for a very spectacular re-entry from where I was sitting,” he said. Big chunks of the burning material came flying by the window.

He wasn’t sure whether the flaming debris was the rocket pack or the heat shield breaking up. “Fortunately,” he told an interviewer,“ it was the rocket pack – or I wouldn’t be answering these questions.”

In the words of President Obama, who awarded him the Presidential Medal of Freedom in 2012: “When John Glenn blasted off from Cape Canaveral atop an Atlas rocket in 1962, he lifted the hopes of a nation. And when his Friendship 7 spacecraft splashed down a few hours later, the first American to orbit the Earth reminded us that with courage and a spirit of discovery there’s no limit to the heights we can reach together. With John’s passing, our nation has lost an icon and Michelle and I have lost a friend. John spent his life breaking barriers, from defending our freedom as a decorated Marine Corps fighter pilot in World War II and Korea, to setting a transcontinental speed record … The last of America’s first astronauts has left us, but propelled by their example we know that our future here on Earth compels us to keep reaching for the heavens. On behalf of a grateful nation, Godspeed, John Glenn.”

Glenn left the Astronaut Corps in 1964 and resigned from the Marine Corps in 1965. And, after some time in private industry ran for and was elected ti the U.S. Senate in 1974, carrying all 88 counties of Ohio. He was re-elected in 1980 with the largest margin in Ohio history. Ohio returned him to the Senate for a third term in 1986. In 1992 he was elected again, becoming the first popularly elected senator from his state to win four consecutive terms. During his last term he was the ranking member of both the Governmental Affairs Committee and the Subcommittee on Air/Land Forces in the Senate Armed Services Committee. He also served on the Select Committee on Intelligence and the Special Committee on Aging. He was considered one of the Senate’s leading experts on technical and scientific matters, and won wide respect for his work to prevent the spread of weapons of mass destruction.

In 1998, Glenn flew on the STS-95 Discovery shuttle flight, a 9-day mission during which the crew supported a variety of research payloads including deployment of the Spartan solar-observing spacecraft, the Hubble Space Telescope Orbital Systems Test Platform, and Glenn’s investigations on space flight and the aging process.

NASA Administrator Charlie Bolden remembers, “Senator Glenn’s legacy is one of risk and accomplishment, of history created and duty to country carried out under great pressure with the whole world watching.”

Today, we honor him for all that he stood for and continues to stand for – grace under pressure, humility, ability, strength.

Godspeed, John Glenn.

6K notes View Post

smparticle2

8 years ago