Stanford University School of Medicine investigators have identified the smoking gun of a "moment of weakness": a signature pattern of electrical activity in a small, deep-brain region just a second or two before a burst of impulsive behavior.

The Stanford scientists discovered similar patterns in mice that had learned to binge eat fatty food and in a human subject anticipating a large cash reward. The researchers also showed, in mice, that supplying a small electrical pulse to the brain region in question, called the nucleus accumbens, as soon as the electrical signature manifested prevented the mice from overindulging in fatty food, while not affecting their intake of normal food, their social behavior or other physical activity.

The findings were published online Dec.18 in the Proceedings of the National Academies of Sciences.

"We've identified a real-time biomarker for impulsive behavior," said Casey Halpern, MD, assistant professor of neurosurgery and the study's senior author. Postdoctoral scholar Hemmings Wu, Ph.D., and neurosurgery resident Kai Miller, MD, Ph.D., share lead authorship.