Study suggests neural mechanism behind contagious yawning

Study suggests neural mechanism behind contagious yawning

These measurements helped the researchers quantify how "excitable" each person's motor cortex was, which they hypothesized would predict his or her propensity for contagious yawning.

And in the latest issue of the journal Current Biology, a group of researchers sets out to solve the mystery of contagious yawning.

Ever wonder why it's impossible not to yawn when you see someone else doing it?

The "contagiousness" of yawns may be rooted in primitive brain reflexes, British researchers report. Together, these findings demonstrate that the instruction to resist yawning significantly increases the urge to yawn and alters how the yawn may be expressed (i.e., stifled yawns rather than full yawns), but it does not alter the individual's propensity for yawning. You would be surprised to know that when 60-70 percent of people see a person yawn in real life or in a photo, they get an urge to replicate the action, according to a new study.

Contagious yawning, which is a common form of echophenomena, is involuntarily triggered when one observes another person yawning. The behavior is hardwired so deep into our motor cortex that trying to stop a yawn actually makes us more likely to do it. Now scientists investigating contagious yawning claim to have discovered what causes us to behave in this fashion. It provides more information as to why people tend to yawn when others do, suggesting that the impulse behind contagious yawning is linked to the level of activity in people's brains.

Professor Jackson said: 'We suggest that these findings may be particularly important in understanding further the association between motor excitability and the occurrence of echophenomena in a wide range of clinical conditions that have been linked to increased cortical excitability and/or decreased physiological inhibition such as epilepsy, dementia, autism, and Tourette syndrome'.

The neural basis for echophenomena is unknown.

The study examined the brain activity of a person when someone "catches" a yawn from another person, or a photo or video. The participants were videoed throughout the experiment so the team could count their yawns later on, and the intensity of their yawns was continuously recorded.

"This research has shown that the urge is increased by trying to stop yourself", said Georgina Jackson, professor at Nottingham.

To test the link between motor excitability and the neural basis for contagious yawning, the researchers used transcranial magnetic stimulation (TMS). "We are looking for potential non-drug, personalized treatments, using TMS that might be effective in modulating imbalances in the brain networks", Jackson said.