In the current edition of the journal Medical Hypotheses, Gallup and Hack tackle the question of why humans yawn, and explore the possible function of the human sinuses.
Yawning occurs not because you are tired, bored, or even need oxygen, they argue. Instead, they say, yawning helps to regulate the brain’s temperature. “The brain is exquisitely sensitive to temperature changes and therefore must be protected from overheating,” the authors write. “Brains, like computers, operate best when they are cool”.
The scientists propose that the walls of the human maxillary sinus (pictured in green above) flex during yawning like a bellows, which in turn facilitates brain cooling. The theory helps explain the function of the human sinuses, which is still debated among scientists. In fact, Hack says everything concerning the human sinuses is debated. “Very little is understood about them, and little is agreed upon even by those who investigate them. Some scientists believe that they have no function at all,” he said.
Essentially the authors present a hypothesis, not previously proposed, that the human sinuses play a role in brain cooling that is driven by yawning.
Beyond the physiological curiosity, the brain cooling theory of yawning also has practical medical implications. Bouts of excessive yawning often precede the onset of seizures in epileptic patients, and predict the onset of pain in people with migraine headaches, explains Gallup. Hack and Gallup predict that excessive yawning might be able to be used as a diagnostic tool in identifying dysfunction of temperature regulation. “Excessive yawning appears to be symptomatic of conditions that increase brain and/or core temperature, such as central nervous system damage and sleep deprivation, says Gallup, a postdoctoral research associate at Princeton.
Previously Gallup conducted experiments to test the yawning theory. For example, he implanted thermocoupled probes in the frontal cortex of rats to measure brain temperature before, during, and after yawning. He found that yawning was preceded by rapid increases in brain temperature and followed by corresponding decreases in brain temperature. Gallup also published a case of two women with chronic and debilitating bouts of yawning 5 to 45 minutes in length, occurring as many as 15 times per day. Both women showed signs of dysfunctioning brain temperature regulation. Mirroring the results of the brain temperature study, one woman took oral temperature measurements before and after yawning episodes, which showed a significant drop in temperature. After receiving that information, the woman reported that methods of behavioral brain cooling provided relief and or postponements of her yawning symptoms.
In 2002, Hack presented findings on the potential role of the maxillary sinus in facilitating brain cooling during functional movements of the jaw. He postulated that human jaw musculature may flex the thin walls of that sinus, ventilating the sinus system and aiding in brain cooling.
Hack and Gallup began collaborating last year. They thought the sinus wall flexing may ventilate the human sinuses similar to that process which is known to occur in birds. “Therefore the proposed ventilation process may assist in controlling brain temperature and insuring the maintenance of integrated functions of the brain,” says Hack.
| Newswise Science News
Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz
Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences