Le bâillement, du réflexe à la pathologie
Le bâillement : de l'éthologie à la médecine clinique
Le bâillement : phylogenèse, éthologie, nosogénie
 Le bâillement : un comportement universel
La parakinésie brachiale oscitante
Yawning: its cycle, its role
Warum gähnen wir ?
 
Fetal yawning assessed by 3D and 4D sonography
Le bâillement foetal
Le bâillement, du réflexe à la pathologie
Le bâillement : de l'éthologie à la médecine clinique
Le bâillement : phylogenèse, éthologie, nosogénie
 Le bâillement : un comportement universel
La parakinésie brachiale oscitante
Yawning: its cycle, its role
Warum gähnen wir ?
 
Fetal yawning assessed by 3D and 4D sonography
Le bâillement foetal
http://www.baillement.com

mystery of yawning 

 

 

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mise à jour du
30 juillet 2019
Sci Rep
2019;9(1):10631
 Infant brain activity in response to yawning
using functional near-infrared spectroscopy
 
Tsurumi S, Kanazawa S, Yamaguchi MK.
Department of psychology, Chuo University, Hachioji, Tokyo
 

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 Tous les articles sur la contagion du bâillement
All articles about contagious yawning
 
Yawning is contagious in human adults. While infants do not show contagious yawning, it remains unclear whether infants perceive yawning in the same manner as other facial expressions of emotion. The authors addressed this problem using functional near-infrared spectroscopy (fNIRS) and behavioural experiments. They confirmed behaviourally that infants could discriminate between yawning and unfamiliar mouth movements. Furthermore, they found that the hemodynamic response of infants to a yawning movement was greater than that to mouth movement, similarly to the observations in adult fMRI study. These results suggest that the neural mechanisms underlying yawning movement perception have developed in advance of the development of contagious yawning.

Le bâillement est contagieux chez l'homme adulte. Bien que les bébés ne manifestent pas cette contagion, il n'est pas clair de savoir si les bébés perçoivent le bâillement de la même manière que d'autres émotions exprimées au niveau de la face. Les auteurs ont abordé ce problème en utilisant la spectroscopie fonctionnelle dans le proche infrarouge (fNIRS) et des expériences comportementales. Ils confirment, sur le plan comportemental, que les nourrissons peuvent faire la distinction entre les mouvements de la bouche lors d'un bâillement et ceux d'autres ouvertures de bouche. De plus, ils constatent que la réponse des nourrissons à un bâillement, appréciée en IRMf, était plus grande que celle d'autres mouvements de la bouche, de la même manière que les observations de l'étude IRMf chez l'adulte. Ces résultats suggèrent que les mécanismes neuronaux sous-jacents à la perception du bâillement se sont développés avant le développement de la contagion des bâillements.


Many studies have shown that contagious yawning can be observed in several mammals1,2,3,4,5,6,7,8,9,10. Provine7 showed that 16 of 30 human adults yawned as a response to videos of a person yawning, while only 7 of 30 adults yawned as a response to videos of a person smiling. Contagious yawning in humans begins to emerge at around age four years10. Massen et al.3 showed that, in chimpanzees, the proportion of contagious yawning in response to yawning videos was significantly higher than that of yawning in response to videos showing chimpanzees' daily behavior. Joly-Mascheroni et al.2 showed that dogs yawned in response to human yawning more than to non-yawning mouth movement. These results from humans and nonhuman suggest that contagious yawning is a strong phenomenon regardless of the species among mammals.
 
On the other hand, it has been reported that contagious yawning seemed not to be observed in human infants. Millen and Anderson9 investigated contagious yawning in infants, and reported null results; they found that only 3 of 22 infants yawned in response to videos showing their mothers yawning. This result suggests that human infants are not generally susceptible to contagious yawning. Considering the developmental trajectory of yawning behavior, spontaneous yawning is observed even in fetuses11. Subsequently, first year infants might discriminate yawning, and then until the preschool age, the contagious yawning behavior would continue to develop according to the development of the primary motor cortex.
 
Although no prior studies succeeded to find contagious yawning in infancy, there are a lot of studies showing significant sensitivity to various facial expressions in infancy12,13. For instance, LaBarbera et al.12 found that 4-month-old infants could discriminate between joyful and neutral faces, and Kotsoni et al.13 showed that 7-month-olds have categorical perception of facial expressions of emotion. To our knowledge, however, the discrimination of yawning faces during infancy has not yet been explored. The present study examined whether infants could discriminate yawning from mouth movement, and showed higher activation of the areas around the superior temporal sulcus (STS) in response to the presentation of yawning.
 
Using fNIRS is one of the most effective methods for investigating the neural correlates of face processing in young infants. A recent series of fNIRS studies measuring the hemodynamic response in infants reported that the temporal areas of the brain were involved in face processing. Otsuka et al.14 showed that the concentration of oxyhemoglobin (oxy-Hb) in the right temporal area of 5- to 8-month-old infants was higher during the presentation of upright faces than during the presentation of inverted faces. In addition, Nakato et al.15 investigated view-invariant face processing in infancy using fNIRS, and found that 8-month-old infants showed greater neural activity in the posterior temporal areas in response to frontal and profile faces. These neural activations were related to the discrimination of faces. Furthermore, it was found that the infants' posterior temporal areas are activated when perceiving facial expressions of emotion and biological motion. Ichikawa et al.16 presented upright and inverted dynamic point-light displays (PLDs) depicting facial expressions of surprise to 7- to 8-month-old infants; higher activation in the right temporal area was observed only during the upright presentation of the dynamic PLDs. Nakato et al.17 reported a higher activation in infants' right posterior temporal area in response to the static angry faces, and in the left area to the static happy faces. Based on the above evidence, we hypothesized that the posterior temporal areas would be activated when viewing the yawning movement.
 
An adult functional magnetic resonance imaging (fMRI) study showed that the bilateral STS was sensitive to yawning movement. Schürmann et al.8 found a significantly higher blood oxygen level- dependent (BOLD) signal in the right posterior STS and bilateral anterior STS while viewing yawning movement compared to that in response to other mouth movements. Thus, we expected that we would be able to identify specific brain activity in response to the presentation of yawning faces during infancy.
 
In this study at first, we conducted behavioral experiments using the preferential looking paradigm to examine the infants' discrimination of yawning. We also tested the inversion effect of the yawning movement in infants as a part of the behavioral experiment. Next, we measured the activity in the bilateral temporal areas of 5- to 8-month-old infants during the presentation of yawning and mouth movements. We hypothesized that yawning movement induces higher activity in the bilateral temporal areas than other mouth movements.
 
 
Discussion
In the current study, we examined infants' discrimination of yawning by using (a) the preferential looking paradigm and (b) fNIRS measurement. In Experiment 1, we explored the infants' looking preference to yawning and mouth movement in 3- to 8-month-old infants. We found that infants of all age groups showed significant preference to yawning movement, but not to mouth movement in the upright condition (Experiment 1a). However, the preference to yawning movement disappeared when the faces were inverted (Experiment 1b). These results suggest that infants could discriminate between yawning and mouth movements. In Experiment 2, we measured the brain activity of 5- to 8-month-old infants in response to the presentation of yawning and mouth movements using fNIRS. Our results showed that the concentration of oxy-Hb increased significantly in the bilateral temporal areas during the presentation of yawning movement, compared with the presentation of objects (vegetables). However, no such brain activity was observed during the presentation of mouth movements.
 
The results of the fNIRS experiment revealed that the concentration of oxy-Hb significantly increased in bilateral temporal areas during the presentation of yawning movement. This finding is consistent with the adult fMRI study8 demonstrating greater bilateral activation in the bilateral superior temporal sulcus in response to yawning movement. In this study, we measured the hemodynamic changes in the bilateral temporal regions near the STS area. The previous studies suggest that these temporal areas are involved in face processing14,15,16. Based on these results, it is suggested that the bilateral temporal areas are involved in the processing of yawning movement even in infants.
 
There are two possible reasons behind the greater activation in bilateral temporal areas to the presentation of yawning in infants. First, this activation could be related to the discrimination of yawning movement, same as in adults8. Second, the familiarity of the stimuli might influence the neural activation in infants' temporal areas. There are two types of familiarity; one is short-term, formed as a result of habituation, and the other is long-term, formed due to daily exposure. The former is formed by habituation during the experimental procedure. Previous fMRI studies also used this familiarity to the neural adaptation procedure, which attenuated the neural activation by the repeated presentation of identical stimuli20, and this procedure was recently used in infant fNIRS face studies21. The latter is formed by the daily exposure to specific faces such as the mother's face and other adult female faces22,23. Recent fNIRS studies showed that the presentation of mother and adult female faces induced higher neural activation22,23. Our results of infants' neural activity of yawning processing reflect this discrimination of yawning movement and the formed long-term familiarity.
 
The neural activity in the bilateral temporal areas of 5- to 8-month-old infants induced by viewing yawning movement indicates that the neural mechanism underlying the processing of yawning movements would develop at least by 5 months of age. This finding is consistent with the development of the ability of face processing14,17,24. The neural activity of temporal areas in response to upright faces was observed even in 5- to 8-months of age14, and the activity of the temporal area induced by facial expressions has been observed in 6- to 7-month-old infants17. Leppänen and Nelson24 also indicated that the neural mechanisms underlying the processing of facial expressions would develop between 5 and 7 months of age. These previous results and our results suggest that the developmental period of discrimination of yawning and facial expressions is overlapped.
 
The results of the behavioral experiments showed that infants could discriminate yawning from other mouth movements. Furthermore, the discrimination of yawning movement was impaired when the yawning movement was inverted, reflecting the face inversion effect25,26,27,28. These two results suggest that infants could discriminate yawning as a facial movement rather than as a low-level visual movement.
 
In the current study, we found that infants who did not demonstrate contagious yawning could discriminate yawning movement. Contagious yawning is related to the social brain regions such as the STS and the mirror-neuron systems29. A recent study showed that the primary motor cortex is the important region for contagious yawning rather than the mirror-neuron systems30. Considering the developmental trajectory of yawning, spontaneous yawning is observed even in fetuses11. After this spontaneous behavior, our study showed that infants aged below one year could discriminate yawning. Until the preschool age, the contagious yawning behavior would continue to develop according to the development of the primary motor cortex10. The neuro-developmental trajectory of contagious yawning in older toddlers and children is a matter for future study.
 
In our study, we investigated the perception of yawning in infants. As a result, we found that infants could discriminate yawning from mouth movement, and also showed the greater activation to yawning in infants' bilateral temporal areas. These results suggest that the development of neural mechanisms of yawning perception precedes the development of contagious yawning.