A new paper has provided data on the neurological pathways activated during the voiding stage of micturition, which might facilitate delineation of the aetiological underpinnings of voiding dysfunction in patients who cannot initiate urination.

“Most studies have only evaluated the bladder in the filling phase, mainly due to challenges that exist with voiding in the functional MRI (fMRI) machine,” explains corresponding author Rose Khavari. However, “our study examined the blood-oxygen-level-dependent (BOLD) signals during fMRI of the brain while healthy females underwent urodynamics testing, including during pressure-flow voiding.”

Pseudocolour representation of a neuronal cluster network activated during micturition displayed on MRI images of the original anatomical space. Image courtesy of R. Khavari.

The study confirmed that brain regions implicated in micturition were activated: a focal region of the pons that initiates urination (the pontine micturition centre [PMC]); motor and executive centres, which might coordinate voiding; and areas linked to emotion, possibly related to the sensations of urination. Importantly, network analysis, based on BOLD-signal sequences, identified short-range and long-range connectivity between the PMC and other neuronal clusters during initiation of voiding.

“Degree of connectivity may be an indicator of the importance of each brain region, identifying hubs for information flow,” says Khavari. “Brain lesions affecting these hubs may have higher impact on task performance, such as voiding, than lesions affecting other regions that are poorly connected; however, this hypothesis must be tested in patients with neuronal lesions.”

Indeed, the authors intend to study brain activity in patients with neurogenic bladder and voiding dysfunction. “Clinical correlation between patients with these chronic urological problems and new discoveries at the level of CNS activity will give a better understanding of this disorder, leading to the development of more-effective diagnostic and treatment modalities,” Khavari concludes.