A resting-state functional MRI study on brain control of bladder storage function

Abstract

Objective In order to observe central responses during naturally occurring urinary bladder storage in healthy subjects, we examined brain areas that control strong bladder sensation by resting-state functional magnetic resonance imaging (rs-fMRI). Methods 44 healthy subjects (19 men and 25 women, between 22 and 50 years of age) were screened in the study from October 2014 to October 2016. All subjects were right-handed and scanned twice under the following two conditions: empty bladder(bladder volume <10 ml)and full bladder ('strong desire to void’, bladder volume between 200 and 400 ml) without the use of filling with a catheter. Brain imaging softwares (SPM8, DPABI, REST) were adopted to analyze the difference in brain-blood perfusion between these two conditions. Voxel-based analysis of the regional homogeneity (ReHo) was performed to analyze rs-fMRI data including the main excitatory regions and inhibitory areas, peak value (X-axis, Y-axis, Z-axis), clusters size(active volume unit: number of voxel), T value (the excitatory and inhibitory extent of brain active regions). Results The rs-fMRI scans of 44 healthy subjects were analyzed. Nine subjects were excluded because of excessive head movements of more than 1.5 mm and 1.5° in rotation. Data sets were obtained from 35 subjects in two states of bladder, empty bladder and strong desires to void. Increased activity during strong desire to void was observed in the prefrontal cortex (PFC), anterior cingulate cortex (ACC), hypothalamus, temporal lobes and left caudate nucleus. Conclusions There are significant changes in the brain’s ReHo during the strong sensation to void. The results suggest that the PFC, the ACC, hypothalamus, temporal lobes and left caudate nucleus play a role in the cerebral control of bladder storage without artificial bladder filling in healthy people. Key words: Urinary bladder; Brain control; Urge; Storage function; Resting-state functional MRI