The Central Pattern Generator (CPG) is a neural circuit
that can produce a rhythmic motor pattern with no need for sensory feedback
or descending control . We have some references for CPGs below. Pub. med. links are provided if applicable, links to full articles are provided if there is no indication of copyright violation.
V1 spinal neurons regulate the speed of vertebrate locomotor outputs. Gosgnach, Simon et. al. Nature, Vol. 440, pp. 215 - 219. 9th March 2006.
How fast can you go? (this article is a non-technical summary of the paper in (2)). Borodinsky, Laura N. Nature, News and Views. Vol. 440, pp. 158-159. 9th March 2006.
Bio-Inspired Emergent Control of Locomotion
Mattia; Arena, Paolo and Fortuna, Luigi. World Scientific Series
on Nonlinear Science. Series A. Vol 48. Editor: Chua, Leon O.