When we heave a deep sigh, there can be many reasons and interpretations, but an unconscious sigh is actually a life-sustaining reflex that helps preserve lung function. Now for the first time, a team of researchers at UCLA and Stanford have pinpointed the origin of the sighing reflex in the brain. Neurobiologist Jack Feldman of UCLA’s Brain Research Institute says this study gave researchers an opportunity to identify a circuit that’s responsible for an easily identifiable behavior.

"And this is one of the holy grails now of neuroscience – is to try and understand how circuits are organized. And the problem that most scientists face is that most of the problems that we’re interested in are just too complicated. With breathing, we have a direct readout of what the brain is doing, so we have a great system for interrogating what’s going on inside the brain. And the number of neurons we had identified were about 200 per side, which is not a lot of neurons, so it was tractable."

This discovery may also help doctors treat patients with breathing disorders.