An fMRI study of the role of suprapontine brain structures in the voluntary voiding control induced by pelvic floor contraction

The present functional magnetic resonance imaging (fMRI) study attempted to identify brain areas involved in such voluntary control of the micturition reflex by performing functional magnetic resonance imaging during a block design experiment in 12 healthy subjects. The protocol consisted of alternating periods of rest and pelvic muscle contraction during empty-bladder condition (EBC) and full-bladder condition (FBC). Repeated pelvic floor muscle contractions were performed during full bladder to induce a stronger contrast of bladder sensation, desire to void and inhibition of the micturition reflex triggering, since the subjects were asked not to urinate. Empty-bladder conditions were applied as control groups. Activation maps calculated by contrast of subtracting the two different conditions were purposed to disclose these brain areas that are involved during the inhibition of the micturition reflex, in which contrast, the SMA, bilateral putamen, right parietal cortex, right limbic system, and right cerebellum were found activated. The combined activation of basal ganglia, parietal cortex, limbic system, and cerebellum might support the assumption that a complex visceral sensory-motor program is involved during the inhibitory control of the micturition reflex.