Functional magnetic resonance imaging during urodynamic testing identifies brain structures initiating micturition.
OBJECTIVE
Normal voiding in neurologically intact patients is triggered by the release of tonic inhibition from suprapontine centers, allowing the pontine micturition center to trigger the voiding reflex. Supraspinal mechanisms of voluntary voiding in humans are just beginning to be described via functional neuroimaging. We further elucidated brain activity processes during voiding using functional magnetic resonance imaging in normal females to gain better understanding of normal voiding as well as changes that may occur in voiding dysfunction.


METHODS
We screened 13 healthy premenopausal female volunteers using baseline clinic urodynamics to document normal voiding parameters. We then recorded brain activity via functional magnetic resonance imaging and simultaneous urodynamics, including the pressure flow voiding phase. After motion correction of functional magnetic resonance images we performed activation and connectivity analyses in 10 subjects.


RESULTS
Group analysis revealed consistent activation areas, including regions for motor control (cerebellum, thalamus, caudate, lentiform nucleus, red nucleus, supplementary motor area and post-central gyrus), emotion (anterior/posterior cingulate gyrus and insula), executive function (left superior frontal gyrus) and a focal region in the pons. Connectivity analysis demonstrated strong interconnectivity of the pontine micturition center with many short-range and long-range cortical clusters.


CONCLUSIONS
Our study is one of the first reports of brain activation centers associated with micturition initiation in normal healthy females. Results show activation of a brain network consisting of regions for motor control, executive function and emotion processing. Further studies are planned to create and validate a model of brain activity during normal voiding in women.
Scott Department of Urology, Baylor College of Medicine, Houston, Texas.
Michael
M
Shy
Radiology Department, Houston Methodist Research Institute, Houston, Texas.
Steve
S
Fung
Department of Urology, Houston Methodist Hospital, Houston, Texas.
Timothy B
TB
Boone
Radiology Department, Houston Methodist Research Institute, Houston, Texas.
Christof
C
Karmonik
Department of Urology, Houston Methodist Hospital, Houston, Texas.
Sophie G
SG
Fletcher
Department of Urology, Houston Methodist Hospital, Houston, Texas. Electronic address: rkhavari@houstonmethodist.org.
Rose
R
Khavari
D000328:Adult; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D009434:Neural Pathways / Q000502:physiology; D012018:Reflex / Q000502:physiology*; D011795:Surveys and Questionnaires; D014554:Urination / Q000502:physiology*; D014563:Urodynamics / Q000502:physiology*
brain; central nervous system; magnetic resonance imaging; urinary tract; urination