Acknowledgments
The authors thank Sherry Loveless for technical assistance in the preparation of this paper. This work was funded, in part, by support from the Center for Neurotechnology Studies of the Potomac Institute for Policy Studies (JG). Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the U.S. Department of Energy under contract DE-AC04-94AL85000. The opinions expressed in this paper are solely those of the authors and do not reflect the position of the Department of Energy or any U.S. governmental agency.