July 2017 MedCity News
The Defense Advanced Research Projects Agency (DARPA) has been working on neural interfaces since 1974, when agency-funded scientists used encephalogram signals to help participants move cursors around a maze. Now, through its Neural Engineering System Design (NESD) program, the agency is sponsoring research into a new generation of technologies that could better enable communication between devices and the brain.
“NESD is pursuing technologies that could someday serve as foundations for future treatments for sensory deficits, such as blindness and deafness,” said Justin Sanchez, who directs DARPA’s Biological Technologies Office. “We envision these systems as neural prostheses, helping the brain to overcome the effects of injury and disease…We expect that the program will also give researchers deeper insights into how the brain processes sensory inputs, and that knowledge could inform a range of future neuroscience efforts.”
First announced in 2016, NESD seeks to translate neurochemical signals into binary code. To achieve this, the agency has awarded contracts to teams at Brown, Columbia, UC Berkeley, Fondation Voir et Entendre (The Seeing and Hearing Foundation) Paradromics and the John B. Pierce Laboratory.
“Our goal with NESD is to communicate with up to one million neurons in the brain, up from the current limit of tens of thousands at a time,” said Sanchez. “We believe that doing so will enable therapeutic applications that offer the user far richer experiences than what has already been demonstrated by technologies such as cochlear implants to treat hearing loss. We also need to shrink the packaging of neural interfaces, overcoming technical hurdles related to biocompatibility and long-term implant..”
The contracted institutions have proposed some bold approaches to access those million neurons. The Brown team seeks to implant 100,000 salt grain-sized sensors in the cerebral cortex to understand speech processing. Researchers at Columbia will use semiconductors placed over the cortex to study vision. Berkeley scientists will develop a miniaturised microscope to interrogate neurons and measure how they respond to visual and tactile stimulation.
“The eyes take in an enormous amount of information every second as photons, and the brain rapidly, and very efficiently, encodes that information as electrochemical signals that we understand as images,” said Sanchez. “For researchers to begin to replicate that process, albeit at much lower scales, they need to figure out how the brain encodes optical inputs and begin to link specific neuronal firing patterns to specific stimuli, making it possible for a machine to read out what the brain is processing.” Ultimately, DARPA sees these projects as another step towards devices that interact directly with the brain – technologies that could ultimately help civilians and service people facing debilitating injuries. “DARPA’s primary constituents are the military services and service members,” said Sanchez. “The brain is involved in every aspect of how military personnel learn complex tasks and manage stressful situations, and it can be subject to extraordinary injury during service to our country. It is the agency’s duty to develop breakthrough technologies to protect service members from harm and, when necessary, help them recover from adverse events.”