[1] Univ Penn, Sch Engn & Appl Sci, Dept Bioengn, Philadelphia, PA 19104 USA
[2] Univ Penn, Perelman Sch Med, Dept Neurosci, Philadelphia, PA 19104 USA
[3] Univ Massachusetts, Dept Neurobiol, Sch Med, Worcester, MA 01655 USA
[4] Harvard Univ, Dept Phys, Cambridge, MA 02138 USA
[5] Harvard Univ, Ctr Brain Sci, Cambridge, MA 02138 USA