Nat. Neurosci. 15, 107–112 (2012); published online 13 November 2011; corrected after print 10 August 2012

In the version of this article initially published, the average durations for N2, cha-1(n2411) and cha-1(p503) shown in Figure 2b (white bars) were incorrect because the n-values used to calculate them included cases in which no nictation was observed:

The error has been corrected in the HTML and PDF versions of the article.