Why Is Yawning Contagious?
Titled 'A neural basis for contagious yawning,' the study conducted by the researchers from the University of Nottingham in the United Kingdom was published Thursday in the academic journal Current Biology. The research suggests that yawning is triggered involuntarily when you see others yawn as it is hard-wired into our brains because of a human trait, "echophenomenon."
"Contagious yawning, in which yawning is triggered involuntarily when we observe another person yawn, is a common form of echophenomena - the automatic imitation of another's words (echolalia) or actions (echopraxia)," the study said.
(http://www.cell.com/current-biology/fulltext/S0960-9822(17)30966-1) The study examined the brain activity of a person when someone "catches" a yawn from another person, or a photo or video. The researchers observed 36 adults, who were made to watch videos of another person yawning. They measured the participants' brain activities during the experiment through transcranial magnetic stimulation (TMS).
In one experiment, researchers asked the participants to try and stifle their yawns while viewing yawn videos or just yawn freely if they were unable to do so. In another experiment, the participants were given the same instructions; however, the researchers also applied electrical currents to the people's scalps, which were meant to stimulate the motor cortex, the part of the brain that controls yawning. Telling the participants to stifle their yawns only increased their urge to yawn, the researchers found.
In other words, "the 'urge' to yawn is increased by trying to stop yourself from doing so," senior study author Georgina Jackson, a professor of cognitive neuropsychology at the University of Nottingham, said in a (https://www.nottingham.ac.uk/news/pressreleases/2017/august/yawning-why-is-it-so-contagious-and-why-should-it-matter.aspx) press statement published by the varsity.
The study determined how each person's motor cortex worked and measured it's "excitability." As the researchers used TMS, it was also possible to increase the "excitability" in the motor cortex and thus even increase people's tendency to contagious yawns.
The researchers found the tendency for "catching" a yawn was associated with the levels of brain activity in a person's motor cortex. If there is more activity in the area, the person will be more inclined to yawn. When the researchers applied electrical currents to the motor cortex in their experiments, the urge to yawn among the participants increased.
Jackson said the findings could have wider uses. "In Tourette's syndrome, if we could reduce the excitability we might reduce the ticks, and that's what we are working on," he said.
Study co-author Stephen Jackson, the professor of cognitive neuroscience, the University of Nottingham, added: "If we can understand how alterations in cortical excitability give rise to neural disorders we can potentially reverse them."
"We are looking for potential non-drug, personalized treatments, using TMS that might be effective in modulating imbalances in the brain networks," he said.