Brain and spinal cord injuries can have a dreadful impact on the life of an individual. While it may be possible someday to repair the brain and reconnect the damaged neural pathways, an alternative approach is to record brain activity, directly decode an individualʼs motor intentions, and then use this input to control robotic devices or reanimate the motionless muscles by microstimulation. While the use of brain activity to generate very simple actions has recently be demonstrated, there remain major obstacles that will need to be overcome before these methods can be used for effective therapies in paralyzed humans. One of these problems is the inability of planar probes to provide a 3-dimensional map of local neural activity. Tetrodes, formed by simply twisting 4 wires together and clipping off the end, have thus often become preferred in primate studies over planar silicon probes, like the Michigan probes. The goal of the proposed research is to develop a fabrication technology which can improve the reliability of tetrodes and support the development of 3-dimensional multi-sensing probes with tens to hundreds of channels. This would enable dramatic improvements in brain-machine interfaces for animals and humans that could serve a variety of clinical and military needs.

The approach is to define electrode arrays on the surface of fine needles that can penetrate the brain with minimum damage. Atom beam proximity lithography, with a useful resolution approaching 20 nm, will be used to achieve the precision and repeatability required for standardizing the probe. A new tough, biocompatible insulating coating will be used to insulate the thin film traces from the needle, each other, and body fluid.