BERKELEY, CA (UroToday.com) - Suprapontine centers are responsible for the voluntary initiation and postponement of micturition. This requires conscious perception of bladder filling and the urge to void. Painful bladder syndrome / interstitial cystitis (PBS/IC) is a syndrome manifested by pain associated with the bladder and bladder hypersensitivity usually associated with urinary frequency. When the bladder is moderately filled, the desire to void can be called forth deliberately, but it can also be suppressed in normals. Kuhtz-Buschbeck and colleagues have attempted to elucidate human brain mechanisms that are active during such intentional modulations of the desire to void with functional magnetic resonance imaging in healthy volunteers.

Brain activity was studied in 22 young women. At moderate bladder filling (350cc) they periodically suppressed or enhanced the urge to void without allowing urine to pass. The intensity of the sensations could be modulated voluntarily. Significant brain activity associated with an increased urge to void was found in the insular cortex, frontal opercula, supplementary motor area, cingulated motor area, right posterior parietal cortex, left prefrontal cortex and cerebellum.

In normal females, frontoparietal brain regions are active when the desire to void is consciously called forth. The left medial frontal cortex is activated when the urge to void is consciously suppressed. Similar studies in patients with PBS / IC would provide a very interesting comparison, and perhaps lead to therapeutic approaches directed to brain regions actively involved in suppressing the urge to void.

Journal of Urology 2005 October; 174:1477-1481