Brain responses to changes in bladder volume and urge to void in healthy men

Abstract

Knowledge of how changes in bladder volume and the urge to void affect brain activity is important for understanding brain mechanisms that control urinary continence and micturition. This study used PET to evaluate brain activity associated with different levels of passive bladder filling and the urge to void. Eleven healthy male subjects (three left- and eight right-handed) aged 19-54 years were catheterized and the bladder filled retrogradely per urethra. Twelve PET scans were obtained during two repetitions of each of six bladder volumes, with the subjects rating their perception of urge to void prior to and after each scan. Increased brain activity related to increasing bladder volume was seen in the periaqueductal grey matter (PAG), in the midline pons, in the mid-cingulate cortex and bilaterally in the frontal lobe area. Increased brain activity relating to decreased urge to void was seen in a different portion of the cingulate cortex, in premotor cortex and in the hypothalamus. Both activation patterns were predominantly bilaterally symmetric and none of the effects could be attributed to the presence of the catheter. However, in some subjects, mostly those reporting intrusive sensations from the urethral catheter, there was a discrepancy between filling volume and urge so that they reported high urge with low volumes. As this 'mismatch' decreased, activation increased bilaterally in the somatosensory cortex. Our findings support the hypothesis that the PAG receives information about bladder fullness and relays this information to areas involved in the control of bladder storage. Our results also show that the network of brain regions involved in modulating the perception of the urge to void is distinct from that associated with the appreciation of bladder fullness.

Cerebral control of the bladder in normal and urge-incontinent women

“…In normal controls some of the brain regions responding to bladder filling (PAG, insula, frontal cortex, Supplementary Tables 5 and 6 Figure 6 is close to a similar region activated by increasing bladder volume in a PET study (Athwal et al, 2001). The hypothalamic region in Supplementary Table 6 and Figure 3 is identical to one responding to decreased urge to void in the same study; it appears to be the perifornical area of the hypothalamus, which in the cat has direct monosynaptic access to the PMC (Holstege, 2005).…”

“…Bladder control is exercised by the brain via a long-loop spinobulbospinal reflex pathway that includes the midbrain periaqueductal gray (PAG) and the pontine micturition center (PMC), which in turn are controlled by a supratentorial network. The main network landmarks are known from animal and clinical observations, and from functional imaging by positron emission tomography (PET) (Athwal et al, 2001;Blok et al, 1997b;Kitta et al, 2006;Matsuura et al, 2002;Nour et al, 2000) or functional magnetic resonance imaging (fMRI) (Di Gangi Herms et al, 2006;Griffiths et al, 2005;KuhtzBuschbeck et al, 2005;Seseke et al, 2006;Zhang et al, 2005).…”

“…Prominent features include insula and anterior cingulate gyrus (ACG) (Athwal et al, 2001;Griffiths et al, 2005). Control tends to be lateralized on the right (Blok et al, 1997b).…”

Role of the Anterior Cingulate Cortex in the Control of Micturition Reflex in a Rat Model of Parkinson's Disease

“…6) 10 . Early studies using functional brain imaging revealed that, the ACC is involved in monitoring bladder filling 11 , withholding urine, and starting micturition 12,13 . However, subsequent studies suggested more complex functions such as a role in 14 integrating afferent information and internal motivational states 12 .…”

“…Early studies using functional brain imaging revealed that, the ACC is involved in monitoring bladder filling 11 , withholding urine, and starting micturition 12,13 . However, subsequent studies suggested more complex functions such as a role in 14 integrating afferent information and internal motivational states 12 . Functional brain imaging studies have shown that there are increased responses in the ACC during withholding urine in normal volunteers 14 and that the ACC is activated when patients have the sensation of urgency and when OAB patients tighten pelvic floor and sphincter muscles and relax the bladder, in order to maintain continence 2 .…”