This article [J. Biomed. Opt. 15, 026020 (2010)] was originally published online on 28 April 2010 with an omission in the acknowledgments. The following sentence has been added to the text:

This work was supported in part by the National Institutes of Health Grant R01HD043154 and The Hartwell Foundation (to M.M.).

All versions of the article were corrected on 5 May 2010.