Are you feeling tired? Even if you aren't, why do you yawn if someone else does?
Recent research put forward that the human tendency for contagious yawning is triggered spontaneously by primitive reflexes in the primary motor cortex, a part of the brain which is responsible for motor function. This study was undertaken by a group of scientists at the University of Nottingham. Titled 'A neural basis for contagious yawning', the research was published in the academic journal Current Biology.
Their findings indicate that our ability to resist yawning when someone else near us yawns is narrow. And our impulse to yawn is increased if we are instructed to resist yawning. But, no matter how hard we try to stifle a yawn, it might change how we yawn but it won't alter our tendency to yawn.
"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." Said Stephen Jackson, Professor of Cognitive Neuroscience, School of Psychology
Echophenomena is not just a human trait
Contagious yawning is triggered involuntarily when we see another person yawn. This is a common form of Echophenomena, the automatic imitation of another's words (echolalia) or actions (echopraxia). Surprisingly, we are not the only species having a propensity for contagious yawning, chimpanzees and dogs do it too.
The neural basis for contagious yawning
The neural basis for Echophenomena is still unknown to the scientific world.
To experiment the relation between motor excitability and the neural basis for contagious yawning, the Nottingham research team used transcranial magnetic stimulation (TMS). They recruited 36 adults to help with their study.
These adults were made to watch video clips showing someone else yawn, and were instructed to either resist or allow themselves to yawn. They were closely monitored, their yawns and stifled yawns were counted. In addition, the intensity of each participant's perceived urge to yawn was continuously recorded. Using electrical stimulus they were also able to increase the urge to yawn.
"This research has shown that the 'urge' is increased by trying to stop yourself. Using electrical stimulation we were able to increase excitability and in doing so increase the propensity for contagious yawning. In Tourettes if we could reduce the excitability we might reduce the ticks and that's what we are working on." Said Georgina Jackson, Professor of Cognitive Neuropsychology in the Institute of Mental Health.
The research has been funded by ESRC doctoral training award to Beverley J Brown and is part of Nottingham's new Biomedical Research Center (BRC) leading research into mental health technology with the aim of using brain imaging techniques to understand how neuro modulation works.
"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" said Prof. Steven Jackson
This latest research follows the publication of their study 'On the functional anatomy of the urge-for-action' which looked at several common neuropsychiatric disorders associated with bodily sensations that are perceived as an urge for action.
Journal Reference:
Georgina M. Jackson et al. A neural basis for contagious yawning. Current Biology, August 2017 DOI: 10.1016/j.cub.2017.07.062
Rama Pandian, she is currently pursuing her Ph.D. in chemical sciences at the VIT University.
No comments: