Thermal imaging reveals sizable shifts in facial temperature surrounding yawning in budgerigars (Melopsittacus undulatus)

Abstract

Accumulating comparative and interdisciplinary research supports a brain cooling function to yawning. In particular, previous research has shown significant decreases in both brain and skull temperature following yawning in mammals. In a recent study using a thermal imaging camera, significant reductions in both the cornea and concha temperature were observed following yawns in the high-yawning subline of Sprague-Dawley rats. Here, we performed a similar experiment to investigate shifts in facial temperature surrounding yawning in an avian species with more typical yawning patterns: budgerigars (). In particular, we took maximal surface temperature recordings from the face (cere or eye) from 13 birds over a one-hour period to track changes before and after yawns. Similar to previous findings in high-yawning rats, we identified significant cooling (-0.36°C) of the face 10-20 seconds following yawning in budgerigars. Consistent with the hypothesis that yawns serve a thermoregulatory function, facial temperatures were slightly elevated just prior to yawning and then decreased significantly below baseline levels immediately thereafter. Similarly, birds that yawned during the trials had consistently higher facial temperatures compared to those that did not yawn. Moreover, yawn latency and overall yawn frequency were strongly correlated with the highest facial temperature recorded from each bird across trials. These results provide convergent evidence in support of a brain cooling function to yawning, and further validate the use of thermal imaging to monitor changes in skull temperature surrounding yawning events.

Chewing on gum alters the expression of contagious yawning

“…In support of this view, yawns tend to cluster around major transitions of activity (Baenninger, Binkley, & Baenninger, 1996), important daily events (Baenninger 1987), and stressful situations and stimuli (Miller, Gallup, Vogel, & Clark, 2010;Eldakar, Tartar, Garcia, Ramirez, Dauzonne & Gallup, 2017). Moreover, yawns are linked with indicators of neurophysiological arousal (Sato-Suzuki, Kita, Oguri, & Arita, 1998;Sato-Suzuki, Kita, Seki, Oguri, & Arita, 2002;Seki, Nakatani, Kita, Sato-Suzuki, Oguri, & Arita, 2003;Kasuya, Murakami, Oshima, & Dohi, 2005;Kita, Kubota, Yanagita, & Motoki, 2008; but see Guggisberg, Mathis, Herrmann, & Hess, 2007) and followed by significant decreases in brain and skull temperature (Shoup-Knox, Gallup, Gallup, & McNay, 2010;Equibar, Uribe, Cortes, Bautista, & Gallup, 2017;Gallup, Herron, Militello, Swartwood, Cortes, & Eguibar, 2017). Ultimately, these neurovascular changes may improve aspects of cognitive processing (Miller et al, 2010;Miller, Gallup, Vogel, & Clark, 2012).…”

Contagious yawning in virtual reality is affected by actual, but not simulated, social presence

“…Yawning is characterized by a powerful gaping of the jaw with deep inspiration, followed by a temporary period of peak muscle contraction and a passive closure of the jaw during expiration 1 . Physiologically, yawns enhance intracranial circulation 2 and facilitate brain cooling 3–5 , which in turn could serve to promote cortical arousal 6 and state change 7 during behavioral transitions. Contagious yawning, which represents the reflexive triggering or release of this response as a result of sensing yawns in others, is a well-documented phenomenon in humans, as seeing, hearing and even thinking about yawning can induce yawn contagion 7,8 .…”

Yawning and Penile Erection Frequencies Are Resilient to Maternal Care Manipulation in the High-Yawning Subline of Sprague–Dawley Rats

“…In fact, 10 s after a yawn happens, there is a reduction in both facial areas that correlates with the reduction in the cortical temperature measured with implanted thermocouple probes in non-HY rats that then returns to basal levels within a short time period (Shoup-Knox et al, 2010;Eguibar et al, 2017b). In another study, we demonstrated in budgerigars that the beak temperature decreased when a yawn happened (Gallup et al, 2017). These experimental data indirectly support the thermoregulatory role of yawning, but it is necessary to obtain more empirical data to support the hypothesis.…”