9630498 Bekoff The long-term goal of the project is to understand the mechanisms underlying the ontogeny of coordinated motor behavior. The studies will focus on the role of sensory experience in the development of behaviors involving leg movements in embryonic and early postnatal life. Both electromyogram (EMG) and kinematic recordings will be quantitatively analyzed to identify effects of altered sensory input or later behavior. Specifically the goal of the research is to explore the issue of whether, in what way, and to what extent alterations in sensory input produce changes in the development of walking. There are four objectives. The first is to examine the role of sensory experience in the postnatal development of walking. The effect of removing or altering input due to load (resistance) or joint proprioception, will be analyzed. This set of experiments will also look at recovery from deficits are limited to walking or whether they generalize to other locomotor or non-locomotor behaviors. A second objective is to further examine the role of sensory input in mature locomotion. The third objective is to examine similar issues in embryos. This will help determine when the mature responses to sensory stimuli develop and will also examine how sensory input is involved in the embryonic development of motor patterns. Finally, the fourth objective is to look at the effects of skipping a step in a developmental sequence. The effects of eliminating particular embryonic behaviors on the subsequent development of walking will be evaluated. Overall the data generated in these studies will significantly increase our understanding of the role of sensory experience in the development of motor behaviors.