This is a continuing project on the basic neurophysiology underlying information processing and rhythmic pattern generation. The goal is to study principles of nerve network operation through use and development of quantitative experimental techniques and computer-based physiologically realistic mathematical models. The focus on rhythmic pattern generators recognizes their significance in producing widely varied neuromuscular behaviors such as walking, talking, eating, writing, swimming, breathing, and heartbeat. A summary of the main features of our research plan includes: 1. Use of a simple animal model that offers ease of research yet has typical pattern generating mechanisms. 2. Use of detailed quantitative measurement of neural properties underlying pattern generation. This is much more readily achieved in simple systems than in ones more complex. 3. Use of testable mathematical models based on quantitative measurement of neuronal properties in the physiological preparation. This allows an assessment of our understanding of underlying mechanisms by comparing model predictions with physiologically generated patterns. 4. Use and development of the model as a research tool to: a) define areas needing further research; b) aid in the design off successive experiments; c) derive measures for parameters not directly observable; d) assign theoretical constraints to the range of network behaviors. The health-related aspects of this line of research may add to the understanding of pattern generation in man. Potential applications range from the study of rhythm disorders of gait, speech, or heart to the development of enhanced neuromuscular abilities sought by the sports physiologist.