Michels Lars, Blok Bertil F M, Gregorini Flavia, Kurz Michael, Schurch Brigitte, Kessler Thomas M, Kollias Spyros, Mehnert Ulrich
Institute of Neuroradiology, University Hospital Zurich, 8091 Zurich, Switzerland.
Department of Urology, Erasmus Medical Center, Erasmus University, Rotterdam, The Netherlands.
Cereb Cortex. 2015 Oct;25(10):3369-80. doi: 10.1093/cercor/bhu140. Epub 2014 Jun 26.
Despite the crucial role of the brain in the control of the human lower urinary tract, little is known about the supraspinal mechanisms regulating micturition. To investigate the central regulatory mechanisms activated during micturition initiation and actual micturition, we used an alternating sequence of micturition imitation/imagination, micturition initiation, and actual micturition in 22 healthy males undergoing functional magnetic resonance imaging. Subjects able to micturate (voiders) showed the most prominent supraspinal activity during the final phase of micturition initiation whereas actual micturition was associated with significantly less such activity. Initiation of micturition in voiders induced significant activity in the brainstem (periaqueductal gray, pons), insula, thalamus, prefrontal cortex, parietal operculum and cingulate cortex with significant functional connectivity between the forebrain and parietal operculum. Subjects unable to micturate (nonvoiders) showed less robust activation during initiation of micturition, with activity in the forebrain and brainstem particularly lacking. Our findings suggest that micturition is controlled by a specific supraspinal network which is essential for the voluntary initiation of micturition. Once this network triggers the bulbospinal micturition reflex via brainstem centers, micturition continues automatically without further supraspinal input. Unsuccessful micturition is characterized by a failure to activate the periaqueductal gray and pons during initiation.
尽管大脑在控制人类下尿路方面起着关键作用，但对于调节排尿的脊髓上机制却知之甚少。为了研究排尿起始和实际排尿过程中激活的中枢调节机制，我们对22名接受功能磁共振成像的健康男性采用了排尿模仿/想象、排尿起始和实际排尿的交替序列。能够排尿的受试者（排尿者）在排尿起始的最后阶段表现出最显著的脊髓上活动，而实际排尿时这种活动明显较少。排尿者开始排尿时，脑干（导水管周围灰质、脑桥）、脑岛、丘脑、前额叶皮质、顶叶岛盖和扣带回皮质出现显著活动，前脑和顶叶岛盖之间存在显著的功能连接。无法排尿的受试者（非排尿者）在排尿起始时激活程度较低，前脑和脑干尤其缺乏活动。我们的研究结果表明，排尿由特定的脊髓上网络控制，该网络对于排尿的自主起始至关重要。一旦这个网络通过脑干中枢触发球海绵体排尿反射，排尿就会自动持续进行，无需进一步的脊髓上输入。排尿失败的特征是在起始时未能激活导水管周围灰质和脑桥。
