Optical Noninvasive Brain-Computer Interface Development: Challenges and Opportunities

The Defense Advanced Research Projects Agency's Revolutionizing Prosthetics program demonstrated the potential for neural interface technologies, enabling patients to control and feel a prosthetic arm and hand, and even pilot an aircraft in simulation. These landmark achievements required invasive, chronically implanted penetrating electrode arrays, which are fundamentally incompatible with applications for the able-bodied warfighter or for long-term clinical applications. Noninvasive neural recording approaches have not been as effective, suffering from severe limitations in temporal and spatial resolution, signal-to-noise ratio, depth penetration, portability, and cost. To help close these gaps, researchers at the Johns Hopkins University Applied Physics Laboratory (APL) are exploring optical techniques that record correlates of neural activity through either hemodynamic signatures or neural tissue motion as represented by the fast optical signal. Although these two signatures differ in terms of spatiotemporal resolution and depth at which the neural activity is recorded, they provide a path to realizing a portable, low-cost, high-performance brain-computer interface. If successful, this work will help usher in a new era of computing at the speed of thought.