Sorry, Bogie, A Sigh Is Not Just A Sigh

The sighs we notice usually accompany emotions like relief or discontent. But our brains are programmed to make us heave an unconscious sigh every five minutes or so — no matter how we feel. "Sighing is vital to maintain lung function," says Jack Feldman, a brain scientist at UCLA.
 These periodic deep breaths reinflate tiny air sacs in the lungs that have gone flat. But the brain circuitry behind those reflexive sighs has been a mystery. Now there's strong evidence from studies in rats that the neural wiring resides in a particular part of the brain stem that regulates breathing, Feldman and a team of researchers report in this week's issue of the journal Nature. continue