EXCEED THE SPACE PROVIDED. Study of the fetus in vivo provides a simple mammalian system that permits investigation of early neurobehavioral development. Understanding the prenatal roots of behavioral organization is fundamental to a deeper understanding of the adaptive capacities and needs of fetuses, full-term neonates, and preterm infants. Behavioral organization, which refers to the nonrandom distribution of motor behavior in space and time, is evident in spontaneous motor activity (SMA), during species-typical action patterns elicited by sensory stimulation, and after motor learning. An organized pattern of movement expressed by the fetus, together with the neural, physiological and biomechanical mechanisms that generate this pattern, constitute an action system. Patterns of movement expressed by an action system may be prescribed by elements of the nervous system, or may emerge as a product of neural plasticity that results from variable motor production, selection of motor synergies, contextual constraint, kinesthetic feedback, and accruing experience. This proposal will explicitly adopt such an interactionist perspective to investigate the prenatal origins of motor coordination and behavioral organization in the rat fetus. Emphasis is placed on understanding the plasticity of mechanisms that govern the early emergence and expression of interlimb coordination in the fetus and neonate. Proposed studies will employ experimental paradigms to promote experience-based changes in motor coordination through explicit training with an interlimb yoke or exposure to other forms of biomechanical constraint of limb movement. The central objective of these experiments is to systematically investigate the role of experience in the prenatal development of motor behavior. Seven core questions will be addressed: (a) Does the rat fetus possess a functional proprioceptive sense, and if so, when does it develop? (b) Does proprioceptive feedback contribute to the neural control of SMA? (c) Does recent kinesthetic experience affect the expression of coordinated behavior? (dj How specific are the effects of prior yoke training on the ability of the fetus to adaptively modify interlimb coordination during a second training session? (e) Does kinesthetic experience exert lasting effects on the ability of the neonate to modify limb coordination? (f) Are neural substrates within the spinal cord sufficient to support the acquisition, persistence, or long-term retention of experience-based changes in motor coordination? (g) Does early kinesthetic experience affect postnatal motor development, as measured by a Perinatal Reflex Assessment Scale or locomotor performance on a motorized treadmill? PERFORMANCE SITE ========================================Section End===========================================
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