Researchers examined a subset of GABA neurons in the circadian rhythm control center within the hypothalamus of the brain. They eliminated GABA signaling of vasopressin-producing neurons only in mice and found that it impaired circadian behavior. Specifically, time spent being active increased every day. Analysis showed a timing mismatch between the center's molecular clock and the behavior. Thus, GABA signaling is required to make sure the timing remains in sync.