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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

mise à jour
28 décembre 2008
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Abstract of the website
 Yawning : its cycles, its roles pdf file
Yawning : unsuspected avenue for a better
understanding of arousal and interoception


Yawning was considered until recently a fossil topic
but, like the phoenix, yawning is rising from the ashes !
Video of a typical Yawn
Yawning is a phylogenetically old, stereotyped event that occurs alone or assiociated with stretching and/or penile erection in humans and in animals from reptiles to birds and mammals under different conditions.
Yawning is a common physiological event that has been described since antiquity. Hypocrates described yawning as an exhaustion of the fumes preceding fever. Modern medicine did not pay a great deal of attention to yawning until the eighties, with advances in neuropharmacology.
Yawning can be divided into 3 distinct phases: a long inspiratory phase, a brief acme and a rapid expiration, frequently but not always associated with stretching, tears, shivering, obstruction of the eustachian canal (causing a reduction in audiologic acuity), followed with a feeling of comfort. The average duration of the yawn is 5 s, (range, 3 to 45 s). The earliest appearance of yawning was observed in a 15-week-old embryo. (see embryology)
This semi-voluntary event increases vigilance and aims to alert when drowsiness occurs ( In animals it subserves behaviour related to stressful situations). Yawning probably has an important role for social communication as well. Excessive or pathological yawning, "chasm", is defined as a compulsive, repetitive action which is not trigered by "physiological" stimuli such as fatigue or boredom, discribed in cases of frontal lobe tumors, encephalitis, progressive supranuclear palsy, following thalamotomy, after electroconvulsive therapy and as an early manifestation of vasovagal response (and a variety of others pathologie-states) and many drugs.
The complex neuronal reflex system of yawning appears to be located in a reticular brainstem system closely related through the diencephalo-hypothalamic network with large associative cortical areas.
The neuro-pharmacology of yawning is complex and knowledge of its mechanisms is incomplete. While under the control of several neurotransmitters, yawning is largely affected by dopamine. Dopamine may activate oxytocin production in the paraventricular nucleus of the hypothalamus, oxytocin may then activate cholinergic transmission in the hippocampus, and finally acetylcholine might induce yawning via the muscarinic receptors of the effectors. In fact, this scheme is over simplified. Many other molecules can modulate yawning, such as nitric oxide, glutamate, GABA, serotonine, ACTH, MSH, sexual hormones and opium derivate peptides, hypocretin. Dopamine involvement in yawning could have practical applications in the study of new drugs or the exploration of neurological diseases such as migraine or psychosis.
Maintaining or attaining a particular level of arousal is an important matter in the life of most vertebrates, and yawning, to the extent that it serves as a means for doing so, should be seen as an important part of adaptative behavior. The physiological, ontogenic and phylogenic findings reviewed here are consistent with this view. (R Baenninger)
Yawning circumstances
How is a yawn triggered?
Neurophysiology of yawning
The curious phenomenon of contagious yawning
New Scientist: The Big Yawn 19 Dec 98 (pdf)
 Why do people yawn ?
Yawning Barbizet J 1959
Yawning Daquin, Micallef, Blin O
Yawning Aloe F
On yawning and its functions Baenninger R
Yawning: an evolutionary perspective Smith EO
Contagious yawning: the role of self-awareness and mental state attribution Platek SM et al
Yawning Surprising facts ans misleading myths about our health Anahad O'Connor
Fetal yawning : a behavior's birth with 4D US revealed O Walusinski
souscrivent à la charte
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Treat this website as a field guide to the terra incognita of yawning, a source of tips about where to find yawning, how to study it, and what it means. You will not find a tidy series of experiments that drive inexorably (and with an intellectual flourish) to a Grand Unified Theory of Yawning. The yawn project is, instead, a catch-as-catch-can interdisciplinary work in progress. Some pieces of the yawning puzzle fit nicely into place, while others are parts of a yet unknown whole.

Useful advice about the process is offered by the embryologist Hans Spemann: " I should like to work like the archeologist who pieces together the fragments of a lovely thing which are alone left to him. As he proceeds, fragment by fragment, he is guided by the conviction that these fragments are part of a whole which, however, he does not yet know. He must be enough of an artist to recreate, as it were, the work of the master, but he dare not build according to his own ideas. Above all, he must keep holy the broken edges of the fragments; in that way only may he hope to fit new fragments into their proper place and thus ultimately achieve a true restoration of the master's creation. "

adapted from R Provine.

 «...seeing a dog and horse and man yawn, makes me feel how much all animals are built on one structure » Charles Darwin 1838 , notebook

Yawning is a stereotyped behaviour present in most mammals from rodents to humans and has been described since antiquity. Hippocrates considered yawning to be an exhaustion of the fumes preceding fever. Modern medicine did not pay much attention to it until the 1980s, when, with advances in neuropharmacology, yawning proved to be a valuable tool for the assessing dopaminergic activity and the pharmacological properties of new drugs. However, its precise role in human physiology is still unknown and its mechanisms remain unclear.
Yawning occurs after waking up, before eating, before sleeping, and in passive activities when it is necessary to maintain a certain level of vigilance. It is then followed by an acceleration of the electroencephalographic rhythms. It does not serve a primary respiratory function and it clearly has a non-verbal communicative status. Nevertheless, it is also a clinical sign in intracranial hypertension, migraine, or iatrogenic side effects of dopaminergic drugs and serotonin reuptake inhibitors. In basal ganglia disorders, yawning is reduced in patients with Parkinson's disease, and occurs more often in patients with Huntington's disease and supranuclear palsy than in controls. In healthy volunteers, apomorphine induces yawning which is also observed at the beginning of the ''on'' periods in Parkinson's disease.
The anatomical structures known to be implicated in the occurrence and control of yawning are the paraventricular nucleus of the hypothalamus(PVN), the hippocampus, the reticular formation, the neostriatum, and the cranial (V, VII, IX, X, XI, XII), cervical(C1&endash;C4), and dorsal nerves. Yawning is probably a reflex answer of the brainstem reticular formation aimed to increase the cortical level of vigilance. Dopamine and oxytocin are the main neurotransmitters implicated in its modulation. Indeed yawning induces sensory efferents from the terminals of the fifth facial nerve to the reticular formation or the PVN through the spinothalamic and hypothalamic tracts. Stimulation of the dopamine D2 receptors of the PVN activates the oxytocin neurones that project either to the pons (reticular formation, locus coeruleus), to the hippocampus, to the insula, or to the orbitofrontal cortex, leading to the transient feeling of wellbeing that follows yawning. This pathway is modulated by acetylcholine, serotonin, opioid peptides, sexual hormones, and orexin.
Contagious yawning is an even more intriguing phenomenon. It is triggered by seeing, hearing, or even thinking about someone else yawning. Contagious yawning does not occur in species that do not recognise themselves in mirrors or in infants younger than two years old. The phenomenon has been investigated with functional magnetic resonance imaging, which implicated the precuneus or the posterior cingulate regions, functional regions associated with the identification of selreferent information, a primitive form of empathy.