Cerebellum and micturition: what do we know? A systematic review

Abstract

Aims: Micturition depends on a complex voluntary and involuntarily neuronal network located at various levels of the nervous system. The mechanism is highly dependent on the hierarchical organization of central nervous system pathways. If the role of the cortex and brainstem centres is well established, the role of other subcortical areas structures, such as the cerebellum is poorly understood. We are interested in discussing the current knowledge on the role of cerebellum in micturition.

Methods: A systematic search is performed in the medical literature, using the PubMed database with the keyword « cerebellum ». The latter is combined with «urination » OR « micturition » OR « urinary bladder ».

Results: Thirty-one articles were selected, focussing on micturition and describing the role of the cerebellum. They were grouped in 6 animal experimental studies, 20 functional brain imaging in micturition and 5 clinical studies.

Conclusions: Although very heterogeneous, experimental and clinical data clearly indicate the cerebellum role in the micturition control. Cerebellum modulates the micturition reflex and participates to the bladder sensory-motor information processing. The cerebellum is involved in the reflex micturition modulation through direct or indirect pathways to major brainstem or forebrain centres.

Keywords: Cerebellum; Micturition; Neural control of lower urinary tract; Urinary bladder; Urination.

Fig. 1

PRISMA flow diagram of studies on the cerebellum role in micturition

Fig. 2

The first part is a schematic representation of the lower urinary tract control showing the voiding reflex (black arrows; Sa: sacral parasympathetic; ON: Onulf nucleus) under brainstem structures in green (PAG: periaqueductal grey; PMC pontine micturition center), forebrain structures in red (SMA: supplementary motor area; dACC: dorsal anterior cingulate cortex) involved in the perception of the desire to void circuit (blue arrows) and the urgency (red arrow). Possible, unidirectional, bidirectional connections of the cerebellum with these structures are showed by purple links and arrows. The second part (below) represents different phases of micturition with the action of the cerebellum when it is known or suggested by the animal experiments, anatomo-clinical studies or the clinical urodynamics results in patients with “pure” cerebellar disorders, and its anatomical activation when it is noticed by the experimental neuroimaging studies. (Produced with the help of the figures of references [1, 39])