Rubrospinal control of static and dynamic fusimotor neurones.
Rubrospinal effects on about 60 extracellularyl recorded gamma-motoneurones were studied in anesthetized cats. All cells were antidromically identified from various muscle nerves. 23 cells were regarded as dynamic as they were activated from a mesencephalic region previously known to influence selectively muscle spindle dynamic sensitivity. The pattern of rubrospinal influence on static fusimotor neurones to different muscles closely followed that previously demonstrated for alpha-motoneurones with pr edominantly excitation of flexor neurones and excitation or inhibition in equal amounts of extensor cells. Dynamic fusimotor neurones were influenced in a strictly reciprocal manner with excitation of flexor cells and inhibition of extensor cells except for a few neurones which could not be reached from nucleur ruber. Evidence was also obtained indicating that the shortest path from nucleus ruber to static fusimotor neurones involves one interneurone.
D000818:Animals; D001369:Axons / Q000502:physiology; D002415:Cats; D004558:Electric Stimulation; D006614:Hindlimb / Q000294:innervation; D008636:Mesencephalon / Q000502:physiology; D009046:Motor Neurons / Q000502:physiology*; D009132:Muscles / Q000294:innervation; D009420:Nervous System; D009431:Neural Conduction; D009433:Neural Inhibition; D009434:Neural Pathways; D013116:Spinal Cord / Q000502:physiology*