[1] Johns Hopkins Univ, Sch Med, Calcium Signals Lab, Baltimore, MD 21205 USA
[2] Johns Hopkins Univ, Sch Med, Dept Biomed Engn, Baltimore, MD 21205 USA
[3] Johns Hopkins Univ, Sch Med, Dept Neurosci, Baltimore, MD 21205 USA
[4] Johns Hopkins Univ, Sch Med, Ctr Cell Dynam, Baltimore, MD 21205 USA