Brain Origin Of Sighing Reflex Discovered
Researchers at the University of California, Los Angeles, have uncovered two clusters of tiny neurons in our brains responsible for sighing.
This new information provides specific insight into just how these network of brain cells create breathing rhythm, researchers say.
"Sighing appears to be regulated by the fewest number of neurons we have seen linked to a fundamental human behavior," said study researcher Jack Feldman, a professor of neurobiology at the University of California, Los Angeles, in a news release. "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."
This vital reflex function typically occurs every five minutes in the average individual, researchers say--or 12 times an hour.
During the study, researchers screened for over 19,000 gene-expression patterns in the animals' brain cells. They found 200 neurons in the brain stem that manufacture and release one of two neuropeptides, which enable brain cells to communicate with one another. However, researchers are still unable to determine which brain cells these neurons communicated with or why.
At the start of the study, ressearchers already knew that a family of peptides also found in humans, influenced the brains ability to breath, including sighing. However, they did not know which genes or neurons controlled them.
The researchers found that blocking one of the peptides cut the animals' sighing rate in half. Silencing both peptides halted the mice's ability to sigh completely. On the other hand, activating the mouse's breathing muscles helped in activating a second set of 200 neurons that increased the rate of sighing.
"These molecular pathways are critical regulators of sighing, and define the core of a sigh-control circuit," Krasnow said. "It may now be possible to find drugs that target these pathways to control sighing."
Triggering sighing could be particularly beneficial for those who cannot breathe deeply on their own, according to Health Day; this might include individuals with an anxiety disorder and other mental health conditions.
"There is certainly a component of sighing that relates to an emotional state. When you are stressed, for example, you sigh more," Feldman said. "It may be that neurons in the brain areas that process emotion are triggering the release of the [sigh-triggering chemicals] -- but we don't know that."
The study is published in the journal Nature.
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