BRAIN CONTROL OF NORMAL AND OVERACTIVE BLADDER
Griffiths D, Derbyshire S, Stenger A, Resnick N. Journal of Urology 2005 (Nov); 174:1862-1867.
Supplementary information not included in the above report on brain responses to bladder filling, measured by fMRI in subjects with and without good bladder control:
detailed information about materials and methods supplementary scan pictures critical discussion
Purpose: Bladder
control problems are common but their cause is often unclear.
Many investigators have sought causes in the lower urinary tract,
but fewer in the supraspinal control system. We have used functional
magnetic resonance imaging (fMRI) to determine brain responses
to bladder filling in subjects with normal and with poor bladder
control (detrusor overactivity).
Materials and Methods: Cerebral responses to bladder
infusion were recorded in 1 males and 11 females without overt
neurological abnormality, aged 26-83 y. Six had good bladder control
and 6 had poor control on prior urodynamics. fMRI was performed
while repeatedly infusing and withdrawing liquid into and out
of the bladder, and monitoring intravesical pressure. Measurements
were made at small and large bladder volumes.
Results: fMRI detected activation of many brain
regions involved in bladder control, including periaqueductal
gray, thalamus, insula, dorsal anterior cingulate, and ventromedial
cerebellum. Orbitofrontal cortex, pontine micturition center and
preoptic hypothalamus were visible in subgroup analyses. Activations
outweighed deactivations and responses became stronger at large
bladder volumes. Among subjects with good control, this strengthening
of response was prominent in the orbitofrontal cortex. Among those
with poor control cortical responses were exaggerated at larger
bladder volumes, except in the orbitofrontal cortex, which remained
weakly activated. This difference was not due to concurrent detrusor
activity.
Conclusions: Poor bladder control is specifically
associated with inadequate activation of orbitofrontal cortex.
Clinically, frontal cortical lesions cause bladder control problems;
this study suggests a similar neurophysiological basis for poor
bladder control in the absence of overt neurological lesion.