Development of locomotion in the rat: the significance of early movements

• Published in: Early human development Vol. 34; no. 1; pp. 89 - 100
• Main Authors: Westerga, J., Gramsbergen, A.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier Ireland Ltd 01.09.1993; New York,NY Elsevier; Amsterdam
• Subjects: Aging; Animals; Biological and medical sciences; Dendrite bundles; Development; Electromyography; Fundamental and applied biological sciences. Psychology; Kinematic analysis; Locomotion; Motor Activity - physiology; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; Motor Neurons - physiology; Muscle activity; Muscle Development; Muscles - innervation; Muscles - physiology; Nervous System - growth & development; Nervous System Physiological Phenomena; Rat; Rats; Restraint, Physical; Space life sciences; Spinal Cord - growth & development; Spinal Cord - physiology; Vertebrates: nervous system and sense organs; Development; Locomotion; Kinematic analysis; Rat; Dendrite bundles; Muscle activity; Motor pathway; Rodentia; Check; Immobilization; Nervous system; Motor neuron; Vertebrata; Mammalia; Newborn animal; Animal; Morphology; Biological effect
• ISSN: 0378-3782; 1872-6232
• DOI: 10.1016/0378-3782(93)90044-U

The development of the nervous system is determined by an interaction between genetic and epigenetic factors. We investigated the possible role of proprioceptive afferent input in the development of locomotion in the rat. Kinematic analysis of locomotion in normal rats reveals a marked transition from immature overground locomotion into the adult pattern around the 15th postnatal day. Around this age, the timing of EMG activity in the tibialis anterior and the gastrocnemius muscle in the hindpaw gains accuracy and the intensity of the EMG increases. In the soleus muscle we observbed an increased regularity in the shape of individual motor unit potentials. Neuroanatomical research revealed the occurrence of dendrite bundles in the motoneuronal pool of the soleus muscle pool from the 16th day as the result of a reorganisation. Immobilisation of one hindlimb in an extended position by casts around the leg from the first till the 20th postnatal day does not interfere with the development of dendrite bundles in the soleus motoneuronal pool. Howeverm, we demonstrated long lasting abnormalities in the timing of the EMG activation patterns in the gastrocnemius and the tibialis anterior muscles. It is conceivable that the experimental interference with afferent feed back is the causative factor of these functional abnormalities.