Abstract
In micturition, the bladder is supposed to empty by a contraction of the detrusor and relaxation of the external sphincter during micturition. By contrast, suprasacral spinal cord injury (SCI) patients usually will have both of them contract simultaneously and result in the so-called detrusor-sphincter dyssynergia. In this study, the cystometrograms of the detrusor and the electromyograms of external urethral sphincter of intact and SCI female Wistar rats are used to investigate the detrusor-sphincter synergia and dyssynergia during micturition. Here, we demonstrate that a temporal “coherent” fractal structure and synchronization of rhythms are two essential features for concerted systemic functions in urodynamics of female Wistar rats. The rhythms of detrusor of the bladder and external urethral sphincter are synchronized around 7Hz and their fractal dimensions as functions of time are temporally “coherent” under 1.5 during voiding in order to facilitate the concerted process. On the other hand, in the spinal cord injured rats, either the temporal coherent structure of fractal or the underlying synchronization of rhythms is impaired, weakened, or absent. Results indicate that, for intact rats, the sphincter muscle is not only active but also recruited in a synchronous fashion with the detrusor. These results have potential implications in the diagnosis of the so-called “dynamical” diseases.