[Effect of hindbrain structures on autogenous periodic motor activity in the rat pup].

Experiments were performed in order to investigate whether the capacity of periodic motor excitation in rats during early postnatal life is the intrinsic feature of immature spinal cord or it is caused by supraspinal input. It was shown that after low spinal cord transection, birsts of periodic activity can still be obtained in m. gastrocnemius but their duration and amplitude are significantly reduced. After brain stem transection at intercollicular level, this type of activity remains unchanged or slightly increased. It was concluded that periodic motor excitation is due to the spinal mechanisms but bulbo-spinal facilitative influences are necessary for normal intensity of autogenic activity.