In the proposed study we will utilize electrophysiological and neuroanatomical techniques to investigate the spinal and supraspinal mechanisms that integrate autonomic and somatic efferent pathways involved in excretory function in the cat. Excretion is an ideal system for studying viscero-somatic interactions, since the performance of both micturition and defecation requires a close coordination between autonomic and somatic effector organs. In this study we will: 1) compare the central projections to the lumbosacral spinal cord from visceral and somatic inputs relevant to excretory function, 2) examine the interneuronal pathways and transmitter mechanisms which process the above viscerosomatic inputs, 3) study the changes in the function of cutaneous and muscle afferents in regulating excret mechanisms during various stages of postnatal development, 4) examine the role of bulbospinal pathways in controlling spinal viscerosomatic integration, 5) study the reorganization of viscerosomatic interactions following spinal cord injury. The ultimate objective in this investigation is to provide a wiring diagram for those spinal pathways which interface spinal viscerosomatic afferent input with the autonomic and somatic efferent outflow. Considerable data is available about the characteristics of incoming and outgoing signals from the spinal cord, but relatively little information is available about the neuronal populatios which interconnect afferent and efferent pathways in the autonomic system or which mediate somatic modulation of autonomic function.