Nature Communications 4: Article number: 2470 (2013); Published: 16 September 2013; Updated: 03 December 2013

There were errors associated with the Supplementary Movies in the version of this Article originally published. The legend of Supplementary Movie 5 was incorrectly associated with Supplementary Movie 4 and Supplementary Movie 5 was omitted. This has now been corrected in the HTML version of the Article; the PDF was correct from the time of publication.