Nat. Neurosci. 19, 419 (2016); published online 23 February 2016; corrected after print 23 February 2016

In the version of this article initially published, the page number for the cross-referenced article was given as 414 instead of 420 and the author name was misspelled Frank instead of Franke. The errors have been corrected in the HTML and PDF versions of the article.