Erratum.
The correct legend for the cover of the 31 March 1978 issue of Science is as follows: Hindfoot prints of a 6-hydroxydopamine-treated rat. Although typically akinetic when it is induced to walk by atropine, the rat's gait is characterized by short steps that may be analogous to that of some Parkinson patients. Here the rat has just been placed on the ground, where it first assumed a broad base of support with the hind legs, then brought its feet closer together and walked forward. [Timothy Schallert, University of Illinois at Urbana-Champaign, Champaign].