DARPA provided funds to six groups working on High-Resolution, Implantable Neural Interfaces

DARPA announced NESD (neural engineering system design) in January 2016 with the goal of developing an implantable system able to provide precision communication between the brain and the digital world. Such an interface would convert the electrochemical signaling used by neurons in the brain into the ones and zeros that constitute the language of information technology, and do so at far greater scale than is currently possible. The work has the potential to significantly advance scientists’ understanding of the neural underpinnings of vision, hearing, and speech and could eventually lead to new treatments for people living with sensory deficits.

“The NESD program looks ahead to a future in which advanced neural devices offer improved fidelity, resolution, and precision sensory interface for therapeutic applications,” said Phillip Alvelda, the founding NESD Program Manager. “By increasing the capacity of advanced neural interfaces to engage more than one million neurons in parallel, NESD aims to enable rich two-way communication with the brain at a scale that will help deepen our understanding of that organ’s underlying biology, complexity, and function.”

Although the goal of communicating with one million neurons sounds lofty, Alvelda noted, “A million neurons represents a miniscule percentage of the 86 billion neurons in the human brain. Its deeper complexities are going to remain a mystery for some time to come. But if we’re successful in delivering rich sensory signals directly to the brain, NESD will lay a broad foundation for new neurological therapies.”

The program’s first year will focus on making fundamental breakthroughs in hardware, software, and neuroscience, and testing those advances in animals and cultured cells. Phase II of the program calls for ongoing basic studies, along with progress in miniaturization and integration, with attention to possible pathways to regulatory approval for human safety testing of newly developed devices. As part of that effort, researchers will cooperate with the U.S. Food and Drug Administration (FDA) to begin exploration of issues such as long-term safety, privacy, information security, compatibility with other devices, and the numerous other aspects regulators consider as they evaluate potential applications of new technologies.

The teams’ approaches include a mix of fundamental research and applied science and engineering. The teams will either pursue development and integration of complete NESD systems, or advance particular aspects of the research, engineering, and mathematics required to achieve the NESD vision, providing new tools, capabilities, and understanding. Summaries of the teams’ proposed research appear below; for additional details, refer to the NESD factsheet.

* A Brown University team led by Dr. Arto Nurmikko will seek to decode neural processing of speech, focusing on the tone and vocalization aspects of auditory perception. The team’s proposed interface would be composed of networks of up to 100,000 untethered, submillimeter-sized “neurograin” sensors implanted onto or into the cerebral cortex. A separate RF unit worn or implanted as a flexible electronic patch would passively power the neurograins and serve as the hub for relaying data to and from an external command center that transcodes and processes neural and digital signals.

Nurmikko aimw to create a “cortical intranet” of tens of thousands of wireless micro-devices — each about the size of a grain of table salt — that can be safely implanted onto or into the cerebral cortex, the outer layer of the brain. The implants, dubbed “neurograins,” will operate independently, interfacing with the brain at the level of a single neuron. The activity of the devices will be coordinated wirelessly by a central communications hub in the form of a thin electronic patch worn on the skin or implanted beneath it.

The system will be designed to have both “read-out” and “write-in” capabilities. It will be able to record neural activity, helping to deepen scientists’ understanding of how the brain processes stimuli from the outside world. It will also have the capability to stimulate neural activity through tiny electrical pulses, a function researchers hope to eventually use in human clinical research aimed at restoring brain function lost to injury or disease.

* A Columbia University team led by Dr. Ken Shepard will study vision and aims to develop a non-penetrating bioelectric interface to the visual cortex. The team envisions layering over the cortex a single, flexible complementary metal-oxide semiconductor (CMOS) integrated circuit containing an integrated electrode array. A relay station transceiver worn on the head would wirelessly power and communicate with the implanted device.

* A Fondation Voir et Entendre team led by Drs. Jose-Alain Sahel and Serge Picaud will study vision. The team aims to apply techniques from the field of optogenetics to enable communication between neurons in the visual cortex and a camera-based, high-definition artificial retina worn over the eyes, facilitated by a system of implanted electronics and micro-LED optical technology.

* A John B. Pierce Laboratory team led by Dr. Vincent Pieribone will study vision. The team will pursue an interface system in which modified neurons capable of bioluminescence and responsive to optogenetic stimulation communicate with an all-optical prosthesis for the visual cortex.

* A Paradromics, Inc., team led by Dr. Matthew Angle aims to create a high-data-rate cortical interface using large arrays of penetrating microwire electrodes for high-resolution recording and stimulation of neurons. As part of the NESD program, the team will seek to build an implantable device to support speech restoration. Paradromics’ microwire array technology exploits the reliability of traditional wire electrodes, but by bonding these wires to specialized CMOS electronics the team seeks to overcome the scalability and bandwidth limitations of previous approaches using wire electrodes.

* A University of California, Berkeley, team led by Dr. Ehud Isacoff aims to develop a novel “light field” holographic microscope that can detect and modulate the activity of up to a million neurons in the cerebral cortex. The team will attempt to create quantitative encoding models to predict the responses of neurons to external visual and tactile stimuli, and then apply those predictions to structure photo-stimulation patterns that elicit sensory percepts in the visual or somatosensory cortices, where the device could replace lost vision or serve as a brain-machine interface for control of an artificial limb.

DARPA structured the NESD program to facilitate commercial transition of successful technologies. Key to ensuring a smooth path to practical applications, teams will have access to design assistance, rapid prototyping, and fabrication services provided by industry partners whose participation as facilitators was organized by DARPA and who will operate as sub-contractors to the teams.

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