Neural control model for the lower urinary tract

A neural network model is proposed which controls a mechanical model of the lower urinary tract (LUT). The network topology is based on neuroanatomical data. The various motoneuron groups in the spinal cord, which act to control the LUT (fig. 1), are represented as single units in the neural network. These units are influenced by a control unit mimicking the supraspinal role in the LUT control. Model simulations show a realistic emptying-filling behaviour of the bladder. By omitting the control unit, an involuntary contraction of the muscular bladder wall is simulated in combination with an increased activity of the urethral sphincter (the closing muscle of the bladder), like the observed muscular dyssynergia of patients with a spinal-cord lesion. A feed-back connection between the urethra and the spinal cord is essential for this observed change in behaviour. In this way, the neural control model can be used to test qualitative descriptions from the literature about the role of the spinal pathways in controlling the LUT.