title: Locomotor role of the corticoreticular-reticulospinal-spinal interneuronal system.
abstract: In vertebrates, the descending reticulospinal pathway is the primary means of conveying locomotor command signals from higher motor centers to spinal interneuronal circuits, the latter including the central pattern generators for locomotion. The pathway is morphologically heterogeneous, being composed of various types of inparallel-descending axons, which terminate with different arborization patterns in the spinal cord. Such morphology suggests that this pathway and its target spinal interneurons comprise varying types of functional subunits, which have a wide variety of functional roles, as dictated by command signals from the higher motor centers. Corticoreticular fibers are one of the major output pathways from the motor cortex to the brainstem. They project widely and diffusely within the pontomedullary reticular formation. Such a diffuse projection pattern seems well suited to combining and integrating the function of the various types of reticulospinal neurons, which are widely scattered throughout the pontomedullary reticular formation. The corticoreticular-reticulospinal-spinal interneuronal connections appear to operate as a cohesive, yet flexible, control system for the elaboration of a wide variety of movements, including those that combine goal-directed locomotion with other motor actions.
authors.affiliation: Department of Physiology, Sapporo Medical University, School of Medicine, Sapporo 060-8556, Japan. matsuk@sapmed.ac.jp
authors.forename: Kiyoji
authors.initials: K
authors.lastname: Matsuyama
authors.forename: Futoshi
authors.initials: F
authors.lastname: Mori
authors.forename: Katsumi
authors.initials: K
authors.lastname: Nakajima
authors.forename: Trevor
authors.initials: T
authors.lastname: Drew
authors.forename: Mamoru
authors.initials: M
authors.lastname: Aoki
authors.forename: Shigemi
authors.initials: S
authors.lastname: Mori
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology / Q000648:ultrastructure; D007395:Interneurons / Q000502:physiology* / Q000648:ultrastructure; D009043:Motor Activity / Q000502:physiology*; D009044:Motor Cortex / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology / Q000648:ultrastructure; D012154:Reticular Formation / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology