Individual cells isolated from biological clock can keep daily time, but are unreliable

Washington University in St. Louis researchers have shown that individual cells isolated from the biological clock can keep daily time all by themselves. However, by themselves, they are unreliable. The neurons get out of synch. The 20,000 neurons comprising the biological clock, remarkably, contain the machinery to generate daily, or circadian, rhythms in gene expression and electrical activity. But the individual cells are sloppy and must communicate with one another to establish a coherent 24-hour rhythm.