New locomotor regions of the brainstem revealed by means of electrical stimulation

New sites in the brainstem eliciting treadmill locomotion have been revealed in decerebrated cats by electrical stimulation. These are the cochlear nuclei, cuneate nucleus, spinocerebellar tracts, and substantia grisea centralis at the level of red nuclei which lie outside the known locomotor regions. Participation of neurons and fibers forming ascending sensory tracts (medial and lateral lemniscus) is of special interest in initiation of locomotion. Collaterals of these tracts pass through the hypothalamic and mesencephalic locomotor regions and may contribute largely to initiation of locomotor generators. Hypotheses about the leading role of non-specific afferent activation of the brainstem reticular formation in initiation of locomotion are put forward.