Recent advances in neuroimaging of bladder, bowel and sexual function

Abstract

Purpose of review In this review, we summarize recent advances in the understanding of the neural control of the bladder, bowel and sexual function, in both men and women. Recent findings Evidence of supraspinal areas controlling the storage of urine and micturition in animals, such as the pontine micturition centre, emerged in the early 20th century. Neurological stimulation and lesion studies in humans provided additional indirect evidence for additional bladder-related brain areas. Thereafter, functional neuroimaging in humans with PET and fMRI provided more direct evidence of the involvement of these brain areas. The areas involved in the storage and expulsion of urine also seem to be involved in the central control of storage and expulsion of feces. Furthermore, most knowledge on the brain control of sexual function is obtained from dynamic imaging in human volunteers. Relatively little is known about the dysfunctional central circuits in patients with pelvic organ dysfunction. Summary fMRI has been the most widely used functional neuroimaging technique in the last decade to study the central control of bladder function, anorectal function and sexual function. The studies described in this review show which sensory and motor areas are involved, including cortical and subcortical areas. We propose the existence of a switch-like phenomenon located in the pons controlling micturition, defecation and orgasm.

How brain diseases affect the lower urinary tract function?

“…Among these, the first study was performed using SPECT, and it revealed activation at the upper pons, left sensorimotor cortex, right frontal cortex, and bilateral somatosensory cortex during bladder filling in healthy volunteers [36]. These findings were consistently reproduced by PET and fMRI using more advanced visuo-mathematical analysis tools; in addition, the activation in the PAG, cerebellum, thalamus, basal ganglia, insular cortex (IC), anterior cingulate (ACG), and prefrontal cortex are consistently observed [37][38][39][40][41][42][43] (Fig. 3A).…”

Between-subject similarity of functional connectivity-based organization of the human periaqueductal gray related to autonomic processing

“…The insula monitors bladder sensory information and, when necessary, shifts our attention to our bladder so that we can look for an appropriate time and place to initiate voiding. These higher level processes and the ultimate decision to void require frontal cortex activity ( Gao et al, 2015 ; Coolen et al, 2020 ; Locke et al, 2022 ). These cortical and subcortical structures are likely to exercise their control over the LUT via the PAG.…”