Functional brain imaging and central control of the bladder in health and disease

Abstract

Central control of the bladder is a complex process. With the development of functional imaging technology and analysis methods, research on brain-bladder control has become more in-depth. Here, we review previous functional imaging studies and combine our latest findings to discuss brain regions related to bladder control, interactions between these regions, and brain networks, as well as changes in brain function in diseases such as urgency urinary incontinence, idiopathic overactive bladder, interstitial cystitis/bladder pain syndrome, urologic chronic pain syndrome, neurogenic overactive bladder, and nocturnal enuresis. Implicated brain regions include the pons, periaqueductal grey, thalamus, insula, prefrontal cortex, cingulate cortex, supplementary motor area, cerebellum, hypothalamus, basal ganglia, amygdala, and hippocampus. Because the brain is a complex information transmission and processing system, these regions do not work in isolation but through functional connections to form a number of subnetworks to achieve bladder control. In summarizing previous studies, we found changes in the brain functional connectivity networks related to bladder control in healthy subjects and patients involving the attentional network, central executive network or frontoparietal network, salience network, interoceptive network, default mode network, sensorimotor network, visual network, basal ganglia network, subcortical network, cerebella, and brainstem. We extend the working model proposed by Griffiths et al. from the brain network level, providing insights for current and future bladder-control research.

Keywords: bladder; brain mapping; functional magnetic resonance imaging; near-infrared spectroscopy; urination.

FIGURE 1

Brain FC and networks related to bladder control. An extended working mode showing the voiding reflex and the brain circuits, especially the interaction between brain regions and networks. FC, functional connectivity; PAG, periaqueductal gray; PMC, pontine micturition center; th, thalamus; SMA, supplementary motor area; SMN, sensorimotor network; ACC, anterior cingulate cortex; SN, salience network; IN, interoceptive network; DLPFC, dorsolateral prefrontal cortex; PPC, posterior parietal cortices; CEN, central executive network; FPN, frontoparietal network; MPFC = medial prefrontal cortex; PCC, posterior cingulate cortex; AG, angular gyrus; DMN, default mode network; BGN, basal ganglia network; AN, attentional network; TPJ, temporoparietal junction. (Extended based on working model by de Groat et al., 2015).