Monthly Archives: April 2021

BrainGate demonstrates a high-bandwidth wireless brain-computer interface (BCI)

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I wrote about some brain computer interface (BCI) work out of Stanford University (California, US), in a Sept. 17, 2020 posting (Turning brain-controlled wireless electronic prostheses into reality plus some ethical points), which may have contributed to what is now the first demonstration of a wireless brain-computer interface for people with tetraplegia (also known as quadriplegia).

From an April 1, 2021 news item on ScienceDaily,

In an important step toward a fully implantable intracortical brain-computer interface system, BrainGate researchers demonstrated human use of a wireless transmitter capable of delivering high-bandwidth neural signals.

Brain-computer interfaces (BCIs) are an emerging assistive technology, enabling people with paralysis to type on computer screens or manipulate robotic prostheses just by thinking about moving their own bodies. For years, investigational BCIs used in clinical trials have required cables to connect the sensing array in the brain to computers that decode the signals and use them to drive external devices.

Now, for the first time, BrainGate clinical trial participants with tetraplegia have demonstrated use of an intracortical wireless BCI with an external wireless transmitter. The system is capable of transmitting brain signals at single-neuron resolution and in full broadband fidelity without physically tethering the user to a decoding system. The traditional cables are replaced by a small transmitter about 2 inches in its largest dimension and weighing a little over 1.5 ounces. The unit sits on top of a user’s head and connects to an electrode array within the brain’s motor cortex using the same port used by wired systems.

For a study published in IEEE Transactions on Biomedical Engineering, two clinical trial participants with paralysis used the BrainGate system with a wireless transmitter to point, click and type on a standard tablet computer. The study showed that the wireless system transmitted signals with virtually the same fidelity as wired systems, and participants achieved similar point-and-click accuracy and typing speeds.

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A March 31, 2021 Brown University news release (also on EurekAlert but published April 1, 2021), which originated the news item, provides more detail,

“We’ve demonstrated that this wireless system is functionally equivalent to the wired systems that have been the gold standard in BCI performance for years,” said John Simeral, an assistant professor of engineering (research) at Brown University, a member of the BrainGate research consortium and the study’s lead author. “The signals are recorded and transmitted with appropriately similar fidelity, which means we can use the same decoding algorithms we used with wired equipment. The only difference is that people no longer need to be physically tethered to our equipment, which opens up new possibilities in terms of how the system can be used.”

The researchers say the study represents an early but important step toward a major objective in BCI research: a fully implantable intracortical system that aids in restoring independence for people who have lost the ability to move. While wireless devices with lower bandwidth have been reported previously, this is the first device to transmit the full spectrum of signals recorded by an intracortical sensor. That high-broadband wireless signal enables clinical research and basic human neuroscience that is much more difficult to perform with wired BCIs.

The new study demonstrated some of those new possibilities. The trial participants — a 35-year-old man and a 63-year-old man, both paralyzed by spinal cord injuries — were able to use the system in their homes, as opposed to the lab setting where most BCI research takes place. Unencumbered by cables, the participants were able to use the BCI continuously for up to 24 hours, giving the researchers long-duration data including while participants slept.

“We want to understand how neural signals evolve over time,” said Leigh Hochberg, an engineering professor at Brown, a researcher at Brown’s Carney Institute for Brain Science and leader of the BrainGate clinical trial. “With this system, we’re able to look at brain activity, at home, over long periods in a way that was nearly impossible before. This will help us to design decoding algorithms that provide for the seamless, intuitive, reliable restoration of communication and mobility for people with paralysis.”

The device used in the study was first developed at Brown in the lab of Arto Nurmikko, a professor in Brown’s School of Engineering. Dubbed the Brown Wireless Device (BWD), it was designed to transmit high-fidelity signals while drawing minimal power. In the current study, two devices used together recorded neural signals at 48 megabits per second from 200 electrodes with a battery life of over 36 hours.

While the BWD has been used successfully for several years in basic neuroscience research, additional testing and regulatory permission were required prior to using the system in the BrainGate trial. Nurmikko says the step to human use marks a key moment in the development of BCI technology.

“I am privileged to be part of a team pushing the frontiers of brain-machine interfaces for human use,” Nurmikko said. “Importantly, the wireless technology described in our paper has helped us to gain crucial insight for the road ahead in pursuit of next generation of neurotechnologies, such as fully implanted high-density wireless electronic interfaces for the brain.”

The new study marks another significant advance by researchers with the BrainGate consortium, an interdisciplinary group of researchers from Brown, Stanford and Case Western Reserve universities, as well as the Providence Veterans Affairs Medical Center and Massachusetts General Hospital. In 2012, the team published landmark research in which clinical trial participants were able, for the first time, to operate multidimensional robotic prosthetics using a BCI. That work has been followed by a steady stream of refinements to the system, as well as new clinical breakthroughs that have enabled people to type on computers, use tablet apps and even move their own paralyzed limbs.

“The evolution of intracortical BCIs from requiring a wire cable to instead using a miniature wireless transmitter is a major step toward functional use of fully implanted, high-performance neural interfaces,” said study co-author Sharlene Flesher, who was a postdoctoral fellow at Stanford and is now a hardware engineer at Apple. “As the field heads toward reducing transmitted bandwidth while preserving the accuracy of assistive device control, this study may be one of few that captures the full breadth of cortical signals for extended periods of time, including during practical BCI use.”

The new wireless technology is already paying dividends in unexpected ways, the researchers say. Because participants are able to use the wireless device in their homes without a technician on hand to maintain the wired connection, the BrainGate team has been able to continue their work during the COVID-19 pandemic.

“In March 2020, it became clear that we would not be able to visit our research participants’ homes,” said Hochberg, who is also a critical care neurologist at Massachusetts General Hospital and director of the V.A. Rehabilitation Research and Development Center for Neurorestoration and Neurotechnology. “But by training caregivers how to establish the wireless connection, a trial participant was able to use the BCI without members of our team physically being there. So not only were we able to continue our research, this technology allowed us to continue with the full bandwidth and fidelity that we had before.”

Simeral noted that, “Multiple companies have wonderfully entered the BCI field, and some have already demonstrated human use of low-bandwidth wireless systems, including some that are fully implanted. In this report, we’re excited to have used a high-bandwidth wireless system that advances the scientific and clinical capabilities for future systems.”

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Brown has a licensing agreement with Blackrock Microsystems to make the device available to neuroscience researchers around the world. The BrainGate team plans to continue to use the device in ongoing clinical trials.

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Here’s a link to and a citation for the paper,

Home Use of a Percutaneous Wireless Intracortical Brain-Computer Interface by Individuals With Tetraplegia by John D Simeral, Thomas Hosman, Jad Saab, Sharlene N Flesher, Marco Vilela, Brian Franco, Jessica Kelemen, David M Brandman, John G Ciancibello, Paymon G Rezaii, Emad N. Eskandar, David M Rosler, Krishna V Shenoy, Jaimie M. Henderson, Arto V Nurmikko, Leigh R. Hochberg. IEEE Transactions on Biomedical Engineering, 2021; 1 DOI: 10.1109/TBME.2021.3069119 Date of Publication: 30 March 2021

This paper is open access.

If you don’t happen to be familiar with the IEEE, it’s the Institute of Electrical and Electronics Engineers. BrainGate can be found here, and Blackrock Microsystems can be found here.

The first story here to feature BrainGate was in a May 17, 2012 posting. (Unfortunately, the video featuring a participant picking up a cup of coffee is no longer embedded in the post.) There’s also an October 31, 2016 posting and an April 24, 2017 posting, both of which mention BrainGate. As for my Sept. 17, 2020 posting (Turning brain-controlled wireless electronic prostheses into reality plus some ethical points), you may want to look at those ethical points.

Use kombucha to produce bacterial cellulose

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The combination of the US Army, bacterial cellulose, and kombucha seems a little unusual. However, this January 26, 2021 U.S. Army Research Laboratory news release (also on EurekAlert) provides some clues as to how this combination makes sense,

Kombucha tea, a trendy fermented beverage, inspired researchers to develop a new way to generate tough, functional materials using a mixture of bacteria and yeast similar to the kombucha mother used to ferment tea.

With Army funding, using this mixture, also called a SCOBY, or symbiotic culture of bacteria and yeast, engineers at MIT [Massachusetts Institute of Technology] and Imperial College London produced cellulose embedded with enzymes that can perform a variety of functions, such as sensing environmental pollutants and self-healing materials.

The team also showed that they could incorporate yeast directly into the cellulose, creating living materials that could be used to purify water for Soldiers in the field or make smart packaging materials that can detect damage.

“This work provides insights into how synthetic biology approaches can harness the design of biotic-abiotic interfaces with biological organization over multiple length scales,” said Dr. Dawanne Poree, program manager, Army Research Office, an element of the U.S. Army Combat Capabilities Development Command, now known as DEVCOM, Army Research Laboratory. “This is important to the Army as this can lead to new materials with potential applications in microbial fuel cells, sense and respond systems, and self-reporting and self-repairing materials.”

The research, published in Nature Materials was funded by ARO [Army Research Office] and the Army’s Institute for Soldier Nanotechnologies [ISN] at the Massachusetts Institute of Technology. The U.S. Army established the ISN in 2002 as an interdisciplinary research center devoted to dramatically improving the protection, survivability, and mission capabilities of the Soldier and Soldier-supporting platforms and systems.

“We foresee a future where diverse materials could be grown at home or in local production facilities, using biology rather than resource-intensive centralized manufacturing,” said Timothy Lu, an MIT associate professor of electrical engineering and computer science and of biological engineering.

Researchers produced cellulose embedded with enzymes, creating living materials that could be used to purify water for Soldiers in the field or make smart packaging materials that can detect damage. These fermentation factories, which usually contain one species of bacteria and one or more yeast species, produce ethanol, cellulose, and acetic acid that gives kombucha tea its distinctive flavor.

Most of the wild yeast strains used for fermentation are difficult to genetically modify, so the researchers replaced them with a strain of laboratory yeast called Saccharomyces cerevisiae. They combined the yeast with a type of bacteria called Komagataeibacter rhaeticus that their collaborators at Imperial College London had previously isolated from a kombucha mother. This species can produce large quantities of cellulose.

Because the researchers used a laboratory strain of yeast, they could engineer the cells to do any of the things that lab yeast can do, such as producing enzymes that glow in the dark, or sensing pollutants or pathogens in the environment. The yeast can also be programmed so that they can break down pollutants/pathogens after detecting them, which is highly relevant to Army for chem/bio defense applications.

“Our community believes that living materials could provide the most effective sensing of chem/bio warfare agents, especially those of unknown genetics and chemistry,” said Dr. Jim Burgess ISN program manager for ARO.

The bacteria in the culture produced large-scale quantities of tough cellulose that served as a scaffold. The researchers designed their system so that they can control whether the yeast themselves, or just the enzymes that they produce, are incorporated into the cellulose structure. It takes only a few days to grow the material, and if left long enough, it can thicken to occupy a space as large as a bathtub.

“We think this is a good system that is very cheap and very easy to make in very large quantities,” said MIT graduate student and the paper’s lead author, Tzu-Chieh Tang. To demonstrate the potential of their microbe culture, which they call Syn-SCOBY, the researchers created a material incorporating yeast that senses estradiol, which is sometimes found as an environmental pollutant. In another version, they used a strain of yeast that produces a glowing protein called luciferase when exposed to blue light. These yeasts could be swapped out for other strains that detect other pollutants, metals, or pathogens.

The researchers are now looking into using the Syn-SCOBY system for biomedical or food applications. For example, engineering the yeast cells to produce antimicrobials or proteins that could benefit human health.

Here’s a link to and a citation for the paper,

Living materials with programmable functionalities grown from engineered microbial co-cultures by Charlie Gilbert, Tzu-Chieh Tang, Wolfgang Ott, Brandon A. Dorr, William M. Shaw, George L. Sun, Timothy K. Lu & Tom Ellis. Nature Materials (2021) DOI: https://doi.org/10.1038/s41563-020-00857-5 Published: 11 January 2021

This paper is behind a paywall.