Nat. Protoc. 9, 575–585 (2014); doi:10.1038/nprot.2014.035; published online 13 February 2014; corrected after print 18 April 2014

In the version of this article initially published, Table 1 contained a number of errors: lateral resolution for two-photon was erroneously stated as 'r divided by the square root of 2' instead of 'r multiplied by the square root of 2'; the illumination intensity for two-photon microscopy was given as '103 times E' instead of '106 times E'; 'lateral resolution' was assigned the incorrect footnote; and reference 11 was incorrectly cited as a source for the table. An additional footnote (a) has also been added to the version that was originally published. These errors have been corrected in the HTML and PDF versions of the article.