Prosthetic limbs that can be maneuvered via neural implants have shown promise in the laboratory, but there are challenges to making them work in the real world. Chief among these obstacles is the neural implants’ nearly inevitable failure over time, often in a matter of weeks.
Researchers from the University of Houston, Texas; Seattle Children’s Research Institute, Washington; the University of Michigan (U-M), Ann Arbor; and Rensselaer Polytechnic Institute (RPI), Troy, New York; have received a three-year, $5.4 million grant from the Defense Advanced Research Projects Agency (DARPA), to identify the combination of factors that cause neural implants to fail.
Badrinath “Badri” Roysam, PhD, chair of the UH Cullen College of Engineering’s department of electrical and computer engineering, is leading the multi-institution team, which includes leaders in the fields of implant design, 3D multispectral imaging, quantitative histology, and pattern recognition. Two companies are also involved in the project.
According to Roysam, neural implants can fail within six to eight weeks. Once implanted, the brain treats these tiny devices like foreign objects and immediately begins to try to isolate them in an effort to protect itself. “The tissue surrounding the device undergoes complex changes that in the end isolate it electrically,” he said. “At this point, [the implant] stops functioning.”
Researchers understand the fundamentals of the brain’s reaction to the implants, but they still have many questions that Roysam’s team will seek to answer.
The work will begin at U-M, where a team led by professor Daryl Kipke, PhD, will build specialized neural implants for use in laboratory testing. Researchers at the Seattle Children’s Research Institute, under the direction of William Shain, PhD, will take three-dimensional images of how different brain cells react to an implant. Those images will be transmitted to UH, where Roysam’s team will run them through a software platform called FARSIGHT, which will analyze the histology, or cellular makeup, of the images. FARSIGHT will then translate these images into data that quantifies the response of each individual brain cell and cell type to the implant.
RPI researchers Kristin Bennett, PhD, and Mark Embrechts, PhD, will then use advanced pattern recognition software and techniques to identify the factors that cause implants to fail prematurely.
Using this information, the RPI researchers will recommend design changes to the U-M researchers, restarting the whole process.
“DARPA has a vision of a future where a soldier who has lost a limb will regain full use of that limb again through advanced technology,” Roysam said. “We’re proud to be part of this effort, which will also benefit civilians. Ideally, the team will be able to make great strides in the understanding of neural implant failure.”
The grant is part of DARPA’s Histology for Interface Stability Over Time program, which is the next phase of its Revolutionizing Prosthetics program. The grant money is being allocated in two phases: $3.2 million will be awarded immediately, and the remaining $2.2 million will be awarded based on performance.
