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The contraction of the detrusor muscle causes the urinary bladder and its mass peristaltic movement, leading to micturition. The vesical plexus of nerves, composed of fibers from the inferior hypogastric plexus, supplies the urinary bladder. The brain plays a crucial part in developing and maintaining bladder control, although its specific involvement in urgency and urine leakage is not well understood. The critical components in the neural control of the bladder and its regulation are the pontine micturition center (located in the mediodorsal aspect of the pons) and the Onuf's nucleus, also known as the sacral micturition center (located between the sacral S2 and S4 segments). The most important cause of a neurogenic bladder is damage or lesions of the spinal cord affecting the pontine micturition center, Onuf's nucleus, or damage to the motor neurons between the pontine and the sacral centers of micturition. Neurogenic bladder can be of several types based on the location of the lesions, such as the autonomous bladder, spastic bladder, atonic bladder, and cortical bladder, all were presented with a unique clinical picture. The classical approach to a case of neurogenic bladder involves a complete assessment of the neurologic system and of pelvic anatomy, while neurogenic bladder rehabilitation may include a bladder retraining program involving intermittent catheterization, timed voiding, medications, and lifestyle modifications. This review article attempts to correlate the neurogenic bladder with various anatomical aspects related to the micturition center in the brain and spinal cord and their control over the urinary bladder, as well as the classical approach toward such a case of neurogenic bladder., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2022, Kumar et al.)

Abstract: In the last decade functional imaging has gained substantial importance for identifying cortical and subcortical brain regions being involved in the micturition circuit. However, possible gender differences are still a matter of debate. In the present study we used functional magnetic resonance imaging (fMRI) to determine micturition related brain regions in healthy men and compared them with those in women to elucidate gender-related differences. fMRI was performed at 3 T in 12 healthy men with urge to void due to a filled bladder. In a non-voiding model they were instructed to contract or to relax the pelvic floor muscles repetitively. As previously reported in women, contraction and relaxation of pelvic floor muscles induced strong activations in the brainstem and more rostral areas in our group of healthy men. In general, men had stronger activations during contraction than women in nearly all identified areas. In contrast, results for the relaxation condition were similar. Some of the differences between contraction and relaxation, formerly detected in females, could be found in our group of males as well. The results suggest that in women and men the same cortical and subcortical networks exist for micturition control. Especially, the well located activations in the putative pontine micturition centre and the periaqueductal grey could be identified in both sexes. However, pelvic floor muscle control seems to induce different activation intensities in men and women. [Copyright &y& Elsevier]

Neurological control of micturition is undertaken by central and peripheral nerve systems through complex neuronal interconnections that are mediated by the action of several neurotransmitters, finally controlling the function of detrusor muscle and external urethral sphincter. In normal circumstances, both muscles must have co-ordinated contractions in such a way that when the detrusor contracts, the external urethral sphincter relaxes. The loss of this co-ordinated action leads to the so-called syndrome of detrusor-sphincter dyssynergia. Without adequate treatment, more than 50% of men with this condition will develop severe complications. There are several neurological diseases that might lead to this condition where a common physiopathology consists of a distortion of the complex neural mechanism innervating the lower urinary tract. Because of this complexity, it is difficult to find a curative treatment providing a definitive solution for a majority of patients. Although most of the currently available therapies only provide partial or temporary solutions, some modalities offer a promising perspective. [ABSTRACT FROM AUTHOR]

The neurocircuitry underlying regulation of bladder and distal colon function by Barrington's nucleus (the pontine micturition centre) was investigated in rats by identifying neurons which were transsynaptically labelled from these viscera, with pseudorabies virus (PRV) or genetically modified forms of PRV [PRV–β-galactosidase (PRV-β-Gal) and PRV–green fluorescent protein (PRV-GFP)]. PRV injection into the bladder or the colon of separate rats suggested an overlap in the distribution of bladder- and colon-related neurons in Barrington's nucleus, as well as a topographical arrangement whereby dorsal neurons were bladder-related and ventral neurons were colon-related. In rats injected with PRV-β-Gal into one viscera and PRV-GFP into another, neurons in the major pelvic ganglion and lumbosacral spinal cord were primarily single-labelled at relatively early survival times. With longer survival times many double-labelled neurons (>70%) appeared in Barrington's nucleus, suggesting that individual Barrington's nucleus neurons are synaptically linked to preganglionic parasympathetic neurons which independently innervate the colon or the bladder. In addition to these dual-labelled neurons, Barrington's nucleus neurons which were single-labelled from either viscera were observed and these exhibited a viscerotopic organization consistent with the single-labelling studies. Together, these findings suggest the existence of three neuronal populations in Barrington's nucleus, one which is synaptically linked to both the bladder and the colon and the other two populations which are specifically linked to either viscera. These anatomical substrates may underlie the central coordination of bladder and colon function and play a role in disorders characterized by a coexistence of bladder and colonic symptoms. [ABSTRACT FROM AUTHOR]

Objective: To review recent literature on the function of the two postulated pontine regions (the M- and L-regions) concerned with lower urinary tract control. Material and Methods: The work reviewed is based on stimulation and lesion experiments and post-operative follow-up in the cat, supported by acute chemical stimulation and blocking experiments in the rat and PET functional brain scanning in humans. Results and Conclusions: The M-region in the cat, homologous to Barrington's micturition centre and to a similar area in humans, is a small region both specific and necessary to voiding, the origin of the final common pathway to bladder and urethra, and the locus of co-ordination of the bladder and the striated sphincter. The L-region in the cat is part of a larger, less specific area that probably serves sphincter control in various circumstances, not exclusively micturition. The homolog of this region in the human or in the rat has not been adequately established. [ABSTRACT FROM AUTHOR]

Micturitional disturbance is rarely mentioned in human herpetic brainstem encephalitis although the pontine tegmentum, called the pontine micturition centre, seems to regulate the lower urinary tract in experimental animals. The case of a 45 year old man, who developed subacute coma and hiccup-like dysrhythmic breathing, and needed assisted ventilation is reported. Examination of CSF showed mononuclear pleocytosis and antibody against herpes simplex virus type 1, but the opening pressure was 90 cm H2O. Brain CT showed brain swelling, predominantly in the posterior fossa, and bilateral subdural effusion. Herpetic brainstem encephalitis was diagnosed, and he received 900 mg/day vidarabine. On regaining consciousness, he had left trochlear nerve palsy, left corectopia, ageusia, and urinary retention. Brain MRI showed right side dominant, bilateral pontine segmental lesions extending slightly to the midbrain and medulla. After two weeks he was able to urinate but showed nocturnal urinary frequency, urinary incontinence, and voiding difficulty. Urodynamic studies showed a residual urine volume of 350 ml and detrusor hyporeflexia on voiding. Micturitional disturbance gradually disappeared together with the neurological signs. The bilateral pontine tegmental lesions in this patient are similar to those in previous findings on brainstem strokes, evidence of the presence of a pontine micturition centre in humans. [ABSTRACT FROM AUTHOR]

Presents a letter to the editor regarding the occurrence of lower urinary track dysfunction in central pontine myelinolysis.