ANDRZEJ KRAUZE
Social mammals—for example, rats and humans—learn to control necessary bodily functions, such as urination (a.k.a. micturition), to keep their living quarters clean or to avoid social faux pas. As a bladder fills with fluid, stretch receptors send nerve impulses to the spinal column, signaling smooth muscle in the bladder wall to contract—a process known as the micturition reflex. Ordinarily the brain overrides the impulse to urinate until an appropriate opportunity arises, but the signaling loop can fail, leading to incontinence.
It is well known that the neurotransmitter gamma-aminobutyric acid (GABA) is involved in micturition, but exactly which part of the brain controls the micturition response has been hard to pin down. Searching for the brain’s urination control switch, University of Birmingham’s Thelma Lovick took ...