L -DOPA-Induced Air-Stepping in the Preweanling Rat: Electromyographic and Kinematic Analyses

• Published in: Behavioral neuroscience 2000-12, Vol.114 (6), p.1174-1182
• Main Authors: Tucker, Laura B, Stehouwer, Donald J
• Format: Article
• Language: English
• Subjects: Afferent Pathways - drug effects; air-stepping; Animals; Animals, Newborn; Behavioral psychophysiology; Behavioral sciences; Biological and medical sciences; Biomechanical Phenomena; Electromyography - drug effects; Female; Fundamental and applied biological sciences. Psychology; Hindlimb - innervation; Joints - innervation; Levodopa - pharmacology; Locomotion - drug effects; Male; Motor Neurons - drug effects; Motor Skills - drug effects; Muscle, Skeletal - innervation; Nervous System - drug effects; Neurology; Neurotransmission and behavior; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Rats; Rats, Sprague-Dawley; Rodents
• ISSN: 0735-7044; 1939-0084
• DOI: 10.1037/0735-7044.114.6.1174

Ontogenetic changes in intralimb coordination may result from maturation of the central pattern for locomotion, maturation of peripheral efferents, changes in afferent modulation of the centrally generated pattern, interactions with the substrate, biomechanical changes within the limb itself, or a combination of these. Electromyograms obtained from three hindlimb extensors of rats on Postnatal Days (PND) 5, 10, 15, or 20, during episodes of coordinated L -DOPA-induced air-stepping, showed that muscle activation preceded extension of the corresponding joints at all ages. The delay between the onset of extensor activity and the onset of joint extension increased during ontogeny and was greatest at PND 20. Ontogenetic changes in the relative timing of muscle activity and corresponding joint movements probably resulted from changes in biomechanical factors, changes in afferent modulation of central motor output, or both.