Locomotor projections from the pedunculopontine nucleus to the medioventral medulla.

Retrograde tracers were injected into the rat medioventral medulla (MED) and the injection site was identified as a locomotion- inducing area by electrical stimulation in the decerebrate preparation. Histological reconstructions showed that about 10% of cholinergic pedunculopontine (PPN) and laterodorsal tegmental (LDT) neurons project to the MED. Also, large numbers of non-cholinergic cells in and around the PPN and LDT were found to project to the MED.