Objectives: First desire to void (FDV) is defined as the first feeling that would lead the patient to pass urine. The aim of the present study is to identify the brain regions activated during FDV.
Methods: Six healthy right-handed male volunteers, aged 31-40 years, agreed to participate in this study. Rather than inserting a urethral catheter, we used a urinary volume monitoring unit and a self-adhesive external condom catheter for this study. Positron emission tomography (PET) scans obtained in the FDV and post-voiding (absence of urge to void) (REST) states were analyzed and compared.
Results: First desire to void state was associated with increased blood flow in the right and left cerebellum, right parahippocampal gyrus (Brodmann area [BA] 30), left superior frontal gyrus (BA9), and left cingulate gyrus (BA32). Rest state was associated with decreased blood flow in the right superior temporal gyrus (BA22), right uncus (BA28), right cingulate gyrus (BA32), left middle temporal gyrus (BA21), and left medial frontal gyrus (BA25). According to region of interest analysis, regional cerebral blood flow of the periaqueductal grey and pons was significantly increased at FDV as opposed to REST.
Conclusions: We located possible brain activity associated with the FDV sensation. Combined activation of the right and left cerebellum, parahippocampal gyrus, superior frontal gyrus, and left cingulate gyrus could be associated with FDV.