作者单位:Univ Calif Los Angeles, Dept Neurosci, Los Angeles, CA 90095 USA[1]Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA[2]Stanford Univ, Dept Bioengn, Stanford, CA 94305 USA[3]Stanford Univ, Dept Neurol & Neurol Sci, Stanford, CA 94305 USA[4]