The sound of yawns makes geladas yawn.

Yawning is undeniably contagious and hard to resist. Interestingly, in our species, even the mere sound of a yawn can trigger this contagious response, especially when the yawner is someone familiar. Together with humans, one other mammal species is known to produce loud and distinct vocalisations while yawning, Theropithecus gelada. Geladas are known for their complex social interactions and rich vocal communication, making them intriguing subjects for studying yawning behaviour. To explore the contagious effect of yawn sounds on geladas, we conducted playback experiments in a zoo-housed colony with animals living in two groups. We exposed them to yawn sounds (Test) or affiliative grunts (Control) produced by males from either their own group or the other one. The results were remarkable, as simply hearing yawn sounds led to yawn contagion in geladas, with multiple responses observed when the yawns came from members of their own group. This finding adds a significant contribution to the research on mimicry and behavioural contagion in primates. Moreover, it raises intriguing questions about the involvement of sensory modalities beyond visual perception in these phenomena.

Social Cognitive Correlates of Contagious Yawning and Smiling.

It has been theorized that the contagion of behaviors may be related to social cognitive abilities, but empirical findings are inconsistent. We recorded young adults' behavioral expression of contagious yawning and contagious smiling to video stimuli and employed a multi-method assessment of sociocognitive abilities including self-reported internal experience of emotional contagion, self-reported trait empathy, accuracy on a theory of mind task, and observed helping behavior. Results revealed that contagious yawners reported increases in tiredness from pre- to post-video stimuli exposure, providing support for the internal experience of emotional contagion, and were more likely to provide help to the experimenter relative to non-contagious yawners. Contagious smilers showed stably high levels of self-reported happiness from pre- to post-video exposure, were more likely to provide help to the experimenter, and had increased accuracy on a theory of mind task relative to non-contagious smilers. There were no differences in self-reported trait empathy for contagious versus non-contagious yawners or smilers. Contagious yawning may be related to some basic (i.e., emotional contagion) and advanced (i.e., helping behavior) sociocognitive processes, whereas contagious smiling is related to some advanced sociocognitive processes (i.e., theory of mind and helping behavior).

Yawning and scratching contagion in wild spider monkeys (Ateles geoffroyi).

Behavioural contagion is a widespread phenomenon in animal species, which is thought to promote coordination and group cohesion. Among non-human primates, however, there is no evidence of behavioural contagion in Platyrrhines (i.e. primates from South and Central America) yet. Here, we investigated whether behavioural contagion is also present in this taxon, by assessing yawning and scratching contagion in a wild group (N = 49) of Geoffroy's spider monkeys (Ateles geoffroyi). We conducted focal samples to examine whether individuals observing the triggering event (i.e. a naturally occurring yawning or scratching event in the group) would be more likely to yawn or scratch in the following 3 min, as compared to individuals who did not observe the triggering event. We ran generalized linear mixed models using a Bayesian approach, and found that the probability of yawning and scratching was higher for individuals observing others yawning and scratching, respectively, as compared to individuals who did not observe such an event. Behavioural contagion did not vary depending on the observer's sex, kinship or relationship quality with the individual performing the triggering event. These findings provide the first evidence for yawning and scratching contagion in a wild group of spider monkeys, and importantly contribute to the debate about the evolutionary origins of behavioural contagion in primates.

Contagious yawning in African painted dogs.

Contagious yawning (CY), which is yawning elicited by sensing another yawning, has been observed only in social species and is considered linked to high sociality. Although this idea-the social communication hypothesis-is supported by previous studies, investigating the occurrence of CY in various species remains necessary. We investigated the occurrence of CY in one of the most social canine species, the African painted dog (Lycaon pictus). We recorded 1387 yawn events from five pairs (10 individuals) in captivity. Temporal analysis showed that subsequent yawns occurred frequently within 15 s or 30 s after spontaneous yawns (SYs). SYs that were detectable by another individual (i.e., visible to the other individual or performed in close proximity) were more likely to elicit subsequent yawns by the other individual. However, the influence of contextual factors on CY differed according to the time window, implying that a conservative time window should be used to reduce overcounting of CY and misattribution of its determinants. The proportion of CY was positively related to time spent in physical proximity to another, a proxy for a social bond. Overall, our results provide the first evidence of CY in African painted dogs and further support the notion that such behavior is prevalent among social animals. They also strongly imply that an appropriate time window should be used to define yawn contagion.

Neural pathways from the central nucleus of the amygdala to the paraventricular nucleus of the hypothalamus are involved in induction of yawning behavior due to emotional stress in rats.

As yawning is often observed in stressful or emotional situations such as tension and anxiety, this suggests that yawning can be considered to be an emotional behavior. However, the neural mechanisms underlying emotion-induced yawning remain unclear. It is well known that the hypothalamic paraventricular nucleus (PVN) is the most important brain structure for induction of yawning behavior. We previously showed that induction of yawning involves the central nucleus of the amygdala (CeA), as well as the PVN. Therefore, emotion-induced yawning could potentially be induced through activation of the direct/indirect neural pathways from the CeA to the PVN. Our present study used a combination of retrograde tracing (injection of Fluoro-Gold (FG) into the PVN) and c-Fos immunohistochemistry to examine the neural pathways that evoke emotion-induced yawning. We additionally performed lesion experiments on the CeA using ibotenic acid, a neurotoxin, to determine whether the CeA is involved in the induction of emotion-induced yawning. Emotional stress by fear conditioning induced yawning behavior, and induced expression of double-labeled cells for c-Fos and FG in the bed nucleus of the stria terminalis (BNST), but not in the CeA. Furthermore, the CeA lesions caused by ibotenic acid abolished the induction of emotion-induced yawning. These results suggest that a neural pathway from the CeA to the PVN via the BNST may be primarily involved in the induction of emotion-induced yawning behavior.

Exploring the incidence and etiopathogenesis of pathological yawning as adverse side effect of psychotropic drugs.

INTRODUCTION: Yawning is a normal, stereotyped physiological event in humans and animal kingdom. When excessive (>3 per 15 minutes), it is termed as pathological yawning (PY). PY could be due to many causes but more commonly associated with side-effect of drugs, notably involving those used in psychopharmacology. Though there are isolated case reports and case-series, there are no large-scale reports of PY. This work attempted to address this lacuna. MATERIAL AND METHODS: The current work attempted to identify characteristics of PY as collated from adverse drug effect databases of Australia (Database of Adverse Event Notifications), Canada (Canada Vigilance Adverse Reaction Online Database) and the United States of America (FDA Adverse Event Reporting System - FAERS). These databases collect and provide public access to reports of adverse events related to drugs and therapeutic goods. They act as a prime pharmacovigilance tool as well as a first-line resource for healthcare professionals, researchers, and the public to monitor the safety of these products and make informed decisions. In the first week of June 2023, open access, unrestricted adverse effect of drug databases were explored, using the word "YAWNING" as the only search term for the side effect of any drug without any restrictions. The collected details of PY cases with their gender, age, reason for drug use, other concomitant complaints as well as the nature of adverse event(s) and its treatment requirements were assessed. Descriptive statistics were used. RESULT: Of the 2655 instances in USA database, 398(15%) had more than 1 suspect drug and in total 578 medications involved. The most commonly involved drugs were apomorphine, sertraline, fluoxetine and paroxetine. In all 341(12.8%) cases reported of YAWN alone or with one another sleep disorder, the most common off ending drug were fluoxetine hydrochloride. DISCUSSION AND CONCLUSION: The neural mechanism and physiology of yawning are explained. This study stresses that a health care professional, particularly mental health professionals and neurologists, should be aware of the importance of PY to deliver the best for the patients under their care. (Neuropsychopharmacol Hung 2023; 25(4): 194-205)

The premonitory phase of migraine is due to hypothalamic dysfunction: revisiting the evidence.

OBJECTIVE: To critically appraise the evidence for and against premonitory symptoms in migraine being due to hypothalamic dysfunction. DISCUSSION: Some premonitory symptoms (e.g. fatigue, mood changes, yawning, and food craving) are associated with the physiologic effects of neurotransmitters such as orexins, neuropeptide Y, and dopamine; all of which are expressed in hypothalamic neurons. In rodents, electrophysiologic recordings have shown that these neurotransmitters modulate nociceptive transmission at the level of second-order neurons in the trigeminocervical complex (TCC). Additional insights have been gained from neuroimaging studies that report hypothalamic activation during the premonitory phase of migraine. However, the available evidence is limited by methodologic issues, inconsistent reporting, and a lack of adherence to ICHD definitions of premonitory symptoms (or prodromes) in human experimental studies. CONCLUSIONS: The current trend to accept that premonitory symptoms are due to hypothalamic dysfunction might be premature. More rigorously designed studies are needed to ascertain whether the neurobiologic basis of premonitory symptoms is due to hypothalamic dysfunction or rather reflects modulatory input to the trigeminovascular system from several cortical and subcortical areas. On a final note, the available epidemiologic data raises questions as to whether the existence of premonitory symptoms and even more so a distinct premonitory phase is a true migraine phenomenon. Video recording of the debate held at the 1st International Conference on Advances in Migraine Sciences (ICAMS 2022, Copenhagen, Denmark) is available at: https://www.youtube.com/watch?v=d4Y2x0Hr4Q8 .

Familiarity modulates both intra- and interspecific yawn contagion in red-capped mangabeys.

Yawn contagion (YC) is, compared to spontaneous yawning, an evolutionary recent phenomenon probably linked to behavioral synchronization in highly social species that is more likely when it involves familiar subjects. Here, we investigate for the first time in monkeys which factors modulate intra- and interspecific YC. Through an experimental approach, we exposed 17 red-capped mangabeys to video stimuli (Yawn vs Control) depicting familiar/unfamiliar red-capped mangabeys and humans, and unfamiliar hamadryas. We found that mangabeys yawned more often in response to Yawn than Control videos independently from the species depicted, demonstrating both intra- and interspecific YC in the tested species. Moreover, both mangabey and human familiar yawning stimuli evoked a stronger yawning response in the subjects compared to the unfamiliar counterparts. Neither the amount of time spent looking frontally at the screen (probability of stimulus perception) nor the levels of self-directed behaviors (a proxy of anxiety) accounted for the results. In conclusion, we provide the first evidence that in non-human primate familiarity modulates both intra- and inter-specific YC. Stimuli emitted by familiar faces somehow ease the mechanisms underlying YC, and this modulation can also apply to heterospecific subjects when previous shared experiences provide the prerequisites for the development of social bonds.

Factors influencing alertness to premonitory symptoms in stroke patients with pre-hospital delay.

OBJECTIVE: The purpose was to explore the alertness of premonitory symptoms in stroke patients with prehospital delay, and to analyze the influencing factors. DESIGN AND SAMPLE: A cross-sectional study using the convenience sampling method was conducted in the neurology department of a general hospital between November 2018 and July 2019. A total of 352 stroke patients were participated in the survey. MEASURES: A hierarchical multiple regression was performed to analyze the factors related to the alertness of premonitory symptoms (0-9 scores) in stroke patients with prehospital delay. RESULTS: The alertness score was 6.53 ± 2.377. The lowest score of 0.55 ± 0.498 was for "Continuous yawning occurs continuously despite no tiredness or lack of sleep is okay, and need not be treated." The hierarchical regression results revealed that symptom onset, symptom change before admission, knowledge, social support were the influencing factors delaying the alertness of premonitory symptoms. Knowledge and support from friends could improve the alertness, while support from family and other support had a notable negative impact. CONCLUSIONS: Stroke patients need to be more alert toward premonitory symptoms. This alertness is related to stroke knowledge and social support. Nurses should formulate interventions and advise stroke patients to improve their stroke knowledge and expand their social network.

Factors affecting yawning frequencies in preterm neonates.

Yawning is a long neglected behavioral pattern, but it has recently gained an increasing interdisciplinary attention for its theoretical implications as well as for its potential use as a clinical marker, with particular regard to perinatal neurobehavioral assessment. The present study investigated the factors affecting yawning frequencies in hospitalized preterm neonates (N = 58), in order to distinguish the effects of hunger and sleep-related modulations and to examine the possible impact of demographic and clinical variables on yawning frequencies. Results showed that preterm neonates yawned more often before than after feeding, and this modulation was not explained by the amount of time spent in quiet sleep in the two conditions. Moreover, second born twins, known to be more prone to neonatal mortality and morbidity, showed increased yawning rates compared to first born twins. Overall, our results are consistent with the hypothesis that yawning frequencies in preterm neonates are modulated by separate mechanisms, related e.g. to hunger, vigilance and stress. These findings, although preliminary and based only on behavioral data, might indicate that several distinct neuropharmacological pathways that have been found to be involved in yawn modulation in adults are already observable in preterm neonates.

Parakinesia Brachialis Oscitans - a Rare Post-Stroke Phenomenon.

Background: Abnormal involuntary movement of paralyzed upper limb during yawning is a rare phenomenon termed as parakinesia brachialis oscitans. Case Report: We describe a 59-year-old gentleman with abnormal involuntary movement of paralyzed right upper limb during yawning 2 weeks following ischemic stroke of left middle cerebral artery territory. Discussion: This is a rare post-stroke phenomenon and its pathophysiological mechanism is poorly understood but this entity highlights possible preserved extrapyramidal pathway which might help in rehabilitating stroke survivors.

Two forms of yawning modulation in three months old infants during the Face to Face Still Face paradigm.

The last decades have seen an increasing interest in the phenomenon of yawning and the dynamics of its modulation, yet no widespread consensus exists on its origins and potential functions. Although most scholars have focused on its potential physiological functions, e.g., related to thermoregulation, arousal modulation or cortisol levels and distress, an emerging line of research has been also investigating the social implications of yawning, including its hypothesized relationship with empathy. In order to explore the dynamics of yawning modulation in infants, we investigated whether a social perturbation-like the one induced by the Face to Face Still Face paradigm, a procedure designed to assess socio-emotional regulation in infants-affects yawning and self-touch hand movements behavior in three-months old infants. As the Still Face episode represents a source of mild distress, we hypothesized that during this phase yawns would be more frequent. Moreover, through the use of path analysis, we investigated potential dynamics of facilitation, inhibition or covariance between the frequencies of these behavioral patterns. Our results showed a sharp increase in self-touch hand movements as well as in the likelihood of yawning during the stressful phase of the procedure (still-face) compared with the two minutes of face-to-face interaction and the reunion episode. Regressions also showed a higher incidence of yawns among girls, consistently with the hypothesis that the analysis of yawning behavior might capture subtle differences in regulatory strategies of infants, possibly related to the transient sex-specific activation of the hypothalamic-pituitary-gonadal axis known as mini-puberty. The path analysis showed a greater consistency between the frequencies of self-touch hand movements during the three episodes of the procedure, compared with yawning. This finding could be a result of distinct yawning-regulating mechanisms being at play in different conditions, e.g., a modulation related to stress and one to social interaction. Taken together, these results suggest that human yawning regulation is an irreducibly complex and multifaceted phenomenon since early age. Moreover, the gender differences highlighted might suggest an early diversification in yawning modulation.

Yawning and airway physiology: a scoping review and novel hypothesis.

BACKGROUND AND PURPOSE: Yawning is a stereotypical complex muscular movement and is commonly executed by most vertebrates. In seconds, the entire airway is fully dilated and surrounding muscles are powerfully stretched, most prominently around the pharynx. To date, yawning has been rarely studied, and as of yet there is no consensus on its main function. MATERIAL AND METHODS: To investigate a mechanical airway function for yawning, a literature search was conducted to relate the frequency of yawning and obstructive airway conditions. RESULTS: The results show that changes in obstructive airway conditions and alteration of the frequency of yawning are temporally related. INTERPRETATION: These relationships, however, cannot be interpreted as causal, nor can they be extrapolated to explain the function of yawning. Yet airway management and yawning share many physiological characteristics. We therefore propose a novel hypotheses: yawning plays a significant role in airway physiology by muscle repositioning and widening the airway lumen, thereby securing long-term oxygenation.

Learning State Assessment in Online Education Based on Multiple Facial Features Detection.

Considering that most of online training is not effectively supervised, this article presents an online leaning state assessment approach which combines blink detection, yawn detection, and head pose estimation. Blink detection is realized by computing the eye aspect ratio and the ratio of closed eye frames to the total frames per unit time to evaluate the degree of eye fatigue. Yawn detection is implemented by computing the aspect ratio of the mouth by using the feature points of the inner lip and combining it with the time of opening mouth to distinguish the mouth state. Head pose estimation is first implemented by calculating the head rotation matrix by matching the feature points of 2D face with the 3D face model and then calculating the Euler angle of the head according to the rotation matrix to evaluate the change of the head pose. Especially in yawn detection, we employ the feature points of inner lips in the calculation of the mouth aspect ratio to avoid the impact of lip thickness of various participants. Furthermore, the blink detection, yawn detection, and head pose estimation are first calculated based on the two-dimensional grayscale image of human face, which could reduce the computational complexity and improve the real-time performance of detection. Finally, combining the values of blinking, yawning, and head pose, multiple groups of experiments are carried out to assess the state of different online learners; then, the learning state is evaluated by analyzing the numerical changes of the three characteristics. Experimental results show that our approach could effectively evaluate the state of online learning and provide support for the development of online education.

Mating-induced analgesia is dependent of copulatory male pattern in high- and low- yawning male rats.

Mating behavior in rodents can modulate pain sensations in both sexes. In males, the execution of mounts, intromissions, and ejaculations induced a progressive increase in their vocalization thresholds induced by tail shocks and other types of noxious stimuli. We selectively inbred two sublines from Sprague-Dawley (SD) rats that differed in their spontaneous yawning frequency. The high-yawning (HY) subline had a mean of 20 yawns/h and a different pattern of sexual behavior characterized by longer interintromission intervals and more sexual bouts that delayed ejaculation. The low-yawning (LY) subline and SD rats yawned as a mean 2 and 1 yawns/h, respectively. So, we determine mating-induced analgesia in HY, LY, and SD male rats by measuring vocalization thresholds in response to noxious electric tail shocks. Our results showed that the magnitude of mating-induced analgesia was lower in HY and LY rats with respect to SD rats. When the rats performed different components of male sexual pattern, both sublines exhibited a significantly lower increase in their vocalization thresholds with respect to SD rats-being sublines less responsive regarding mating-induced analgesia. Pain modulation mechanisms depend on responses to stress, so the low levels of analgesia obtained in the yawning sublines may be due either to differences in their response to stress in other paradigms, or to atypical performance of male sexual behavior during mating, an event which as a stressful event in rats. Therefore, the yawning sublines are a suitable model for analyzing how a different temporal pattern in the display of male sexual behavior affects analgesia mechanisms. Our results concur with Wistar rats with different endophenotypes that could apply to humans as well.

Yawn contagion in bonobos: Another group, another story.

In primates, yawn contagion (the yawning response elicited by others' yawn) is variably influenced by individual (e.g., sex, age) and social factors (e.g., familiarity) and possibly linked to interindividual synchronization, coordination, and emotional contagion. Two out of three studies on yawn contagion in bonobos (Pan paniscus), found the presence of the phenomenon with mixed results concerning the effect of familiarity and no replication on its modulating factors. To address this puzzling issue, we recorded all occurrences data on yawn contagion in a captive bonobo group (March-June 2021; 18 individuals; La Vallée des Singes, France). Contrary to chimpanzees and humans, the number of triggering yawns increased contagion, possibly owing to a higher stimulus threshold. This aspect may explain the interindividual variability observed in yawn contagion rates. In subjects under weaning, we did not detect yawn contagion and, as it occurs in certain human cohorts, yawn contagion declined with age, possibly due to reduced sensitivity to others. Females responded more than males and elicited more responses from females when showing sexual swelling. As reproductive females are central in bonobo society, our results support the hypothesis that-as in other Hominini-the most influential sex can influence yawn contagion. The relationship quality (measured via grooming/play) did not affect yawn contagion, possibly due to bonobos' xenophilic nature. Overall, this study confirms the presence of yawn contagion in bonobos and introduces new elements on its modulating factors, pointing toward the necessity of cross-group studies.