Nature Reviews Neuroscience 16, 94–108 (2015)

On page 97 of the above article, the final line of the text of Box 1 should have read 'The figure part b, bottom, is adapted (by rearranging and annotating the smoothed data line in the original figure), with permission, from Berg, R. W. and Kleinfeld, D. Rhythmic whisking by rat: retraction as well as protraction of the vibrissae is under active muscular control. J. Neurophysiol. 89, 104–117 (2003)'. This has been corrected in the online version.