Target cells of rubrospinal tract fibres within the lumbar spinal cord

This short review concerns the problem of how the red nucleus contributes to the initiation and execution of movements. However, it deals with only one aspect of this problem, and focuses on the question of which intrinsic spinal interneuronal networks are used by neurones in the red nucleus to induce movements. The evidence is reviewed that neurones in the red nucleus have access to interneurones with a great variety of functions, excitatory as well as inhibitory. These interneurones are interposed in a number of different spinal reflex pathways, and include both the first and last order interneurones of these pathways. Through them different sets of motoneurones may be affected. All types of interneurones involved are also used by other descending systems, e.g. by cortico- and/or reticulospinal systems, and integrate descending commands with information from various peripheral receptors.