Cerebral control of bladder function.

Symptoms such as overactive bladder represent disorders of bladder control. Functional brain scanning by positron emission tomography and functional magnetic resonance imaging suggest that normal control is exerted by a network of regions in the emotional nervous system, including periaqueductal gray, thalamus, insula, anterior cingulate, and prefrontal cortex. The network receives afferent signals, converts them to bladder sensations, and brings them to conscious attention, together with an unpleasant affect (desire to void) that motivates bladder emptying and thus maintains homeostasis. In patients with poor control, brain response to bladder filling differs; cerebral control is abnormal, even in the absence of involuntary detrusor contraction. Behavioral therapy and electrical stimulation appear to be possible treatments.