Nat. Med. 13, 1102–1107 (2007); published online 2 September 2007; corrected after print 17 September 2007

In the version of this article initially published, the name of one person acknowledged was misspelled, and reference 4 should have been:

Moghaddam, B. & Adams, B.W. Reversal of phencyclidine effects by a group II metabotropic glutamate receptor agonist in rats. Science 281, 1349–1352 (1998).

These errors have been corrected in the HTML and PDF versions of the article.