"You must remember this: a kiss is just a kiss, a sigh is just a sigh." Contrary to these words immortalized by the piano singer in the film "Casablanca," a sigh is far more than a sigh. Letting loose with an unconscious sigh is actually a life-sustaining reflex that helps preserve lung function. Now, a new study by researchers at UCLA and Stanford has pinpointed two tiny clusters of neurons in the brain stem that are responsible for transforming normal breaths into sighs. Published online on February 8, 2016 in Nature, the discovery may one day allow physicians to treat patients who cannot breathe deeply on their own -- or who suffer from disorders in which frequent sighing becomes debilitating. The Nature article is titled “The Peptidergic Control Circuit for Sighing.” "Sighing appears to be regulated by the fewest number of neurons we have seen linked to a fundamental human behavior," explained Jack Feldman, Ph.D., a Professor of Neurobiology at the David Geffen School of Medicine at UCLA and a member of the UCLA Brain Research Institute. "One of the holy grails in neuroscience is figuring out how the brain controls behavior. Our finding gives us insights into mechanisms that may underlie much more complex behaviors." According to Mark Krasnow, Ph.D., a Professor of Biochemistry and Howard Hughes Medical Institute Investigator at the Stanford University School of Medicine, the new findings shed light on the network of cells in the brain stem that generates breathing rhythm. "Unlike a pacemaker that regulates only how fast we breathe, the brain's breathing center also controls the type of breath we take," Dr. Krasnow said. "It's made up of small numbers of different kinds of neurons. Each functions like a button that turns on a different type of breath.Login Or Register To Read Full Story