Micturition and the soul

AbstractThere is a close connection between micturition and emotion. Several species use micturition to signal important messages as territorial demarcation and sexual attraction. For this reason, micturition is coordinated not in the spinal cord but in the brainstem, where it is closely connected with the limbic system. In cat, bladder afferents terminate in a cell group in the lateral dorsal horn and lateral part of the intermediate zone. Neurons in this cell group project to supraspinal levels, not to the thalamus but to the central periaqueductal gray (PAG). Neurons in the lateral PAG, not receiving direct sacral cord afferents, project to the pontine micturition center (PMC). The PMC projects directly to the parasympathetic bladder motoneurons and to sacral GABA‐ergic and glycinergic premotor interneurons that inhibit motoneurons in Onuf's nucleus innervating the external striated bladder sphincter. Thus, PMC stimulation causes bladder contraction and bladder sphincter relaxation, i.e., complete micturition. Other than the PAG, only the preoptic area and a cell group in the caudal hypothalamus project directly to the PMC. The ventromedial upper medullary tegmentum also sends p