These studies demonstrate the presence of the MLR in the rat brain. Controlled locomotion on a treadmill could be induced by low level stimulation (less than 50 microA) of an area in the posterior midbrain following a precollicular-prenigral brainstem transection. This area included the lateral part of the cuneiform nucleus and anterior as well as posterior portions of the pedunculopontine nucleus. In addition, the presence of a subthalamic locomotor region in the fields of Forel was determined in rats after prethalamic transections.