A deeper exploration of functional connectivity of brain regions regulating bladder function in healthy adults

Functional magnetic resonance imaging (fMRI) has been the primary tool in human research for studying and advancing our understanding of neural control of the bladder. Although the current working model identifies several brain regions involved in bladder storage, there are unknowns regarding the full extent of collaboration among these regions. This study analyzes the changes in the resting state functional connectivity (rsFC) network involving regions of the brain, brainstem, and cerebellum in healthy adults with respect to conventional pairwise rsFC and four rsFC global network statistics. Healthy adult males and females (n=15), ages 22-33, were asked to consume 472-750 mL of water, empty their bladder, and enter the fMRI scanner, after which the "control" resting-state fMRI (rs-fMRI) scans were obtained. Participants remained in the scanner until they indicated a feeling of strong desire to void, or until 10 min had elapsed, at which point "strong desire to void" rs-fMRI scans were acquired. Functional connectivity (FC) analysis was performed using 19 a priori regions of interest (ROIs) in the brain, specifically incorporating the brainstem and cerebellum from previous studies. Statistical significance was gauged via t-tests with Bonferroni correction for multiple hypothesis testing. Our results revealed significance, p<0.05, in the rsFC network, where the average rsFC during the strong sensation state was higher than in the control state. The pontine micturition center and cerebellum were associated with this significant increase in the average degree of 19 ROIs. The contrasts in network statistics were more substantial than the contrasts in pairwise rsFC.