1. Department of Materials Science and Engineering Massachusetts Institute of Technology Cambridge MA 02142 USA
2. Research Laboratory of Electronics Massachusetts Institute of Technology Cambridge MA 02139 USA
3. McGovern Institute for Brain Research Massachusetts Institute of Technology Cambridge MA 02139 USA
4. Department of Health Sciences and Technology Swiss Federal Institute of Technology Zürich 8093 Switzerland
5. Computer Science and Artificial Intelligence Lab Massachusetts Institute of Technology Cambridge MA 02139 USA
6. Institute of Biomedical Engineering National Chiao Tung University 1001 University Road Hsinchu 30010 Taiwan
7. Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA 02142 USA
8. Department of Bio and Brain Engineering Korea Advanced Institute of Science and Technology Daejeon 34141 Republic of Korea
9. Department of Brain and Cognitive Sciences Massachusetts Institute of Technology Cambridge MA 02139 USA