The development of rhythmic forms of movement such as crawling and breathing is dependant on groups of pattern generating neurons in the central nervous system, but the sensory inputs involved remain unclear. In March 14 Nature, Maximiliano Suster and Michael Bate from University of Cambridge, UK, show that sensory transmission is not required for the development of a central circuit that is adequate for producing rhythmic movements.

Suster and Bate engineered Drosophila embryos and larvae that had either no peripheral sensory function or almost no peripheral sensory neurons. They found that in the complete absence of sensory input crawling still develops, but the polarity of movements is deranged, and backward peristaltic waves predominate (Nature 2002, 416:174-178).

"The developmental significance of this motor activity is not clear, but one possibility is that, as in sensory systems, activity in the motor system is a prerequisite for the proper...