The release of
oxytocin in the PVN is an important regulator for yawning
and pair bonding
For more than one hundred years, scientists have been
developing and applying a wide range of approaches to
understand the relationship between brain activity and
behaviour. Indeed, this question constitutes one of the
holy grails of modern neuroscience research. These
investigations range from the study of the molecular
machinery that regulates circadian rhythms to the study
of the cognitive control of emotional information.
We present two examples that illuminate the first
thinking model and that highlights the crucial insights
gained from work linking gene networks manipulations to
specific systems that underlie behavior, in our case
"yawning".
By inbreeding Jose R.
Eguibar et al. have developed 2
Sprague-Dawley sublines: one of them yawns
spontaneously at a low frequency (LY), the other at a
higher level (HY). Yawning activity in HY females is
slightly but significantly higher than in LY females. In
both sublines females yawn much less than males,
confirming the sexual dimorphic character of this
behavior. Biometrical analysis of non-segregating
populations (Pl, P2 and FI) after reciprocal genetical
crosses between animals of the HY and LY sublines,
suggested that one pair of genes is involved in the
difference between these sublines and that the LY (P 1)
subline is partially dominant over the HY (P2) one.
Oxytocin is known to reduce anxiety and stress in
social interactions as well as to modulate approach
behavior. In rodents, oxytocin improves social memory and
plays an important role in affiliation behavior such as
pair-bonding and maternal care. In humans, oxytocin also
seems to be a potent modulator in the processing of
social stimuli.
The release of oxytocin in the PVN is a key factor
for the generation of yawning, not only by this
peptide, but also in this part of the brain the
dopaminergic, excitatory amino acids, nitric oxide
converge to increase yawning frequency, suggesting
that neural mechanisms in the hypothalamus are important
regulators for yawning and pair bonding.
Yawning, given its complex neurobiological nature
and close association with the central release of
oxytocin, one might best keep an open mind with regard to
its potential value as a social signal and capacity for
inducing a calming or pacifying effect. The multifaced
role of central oxytocin in the expression of sexual
behavior (perhaps explaining the occurrence of
stress-related penile erections), social
recognition,attachement and bonding, and the diminution
of irritability and agression, suggests that yawning may
help to modulate aversive emotional arousal produced in
association with stressful social interaction.
La
libération d'ocytocine dans le PVN régule
bâillement et affiliation
Depuis plus de 100 ans, les scientifiques ont
multiplié les approches et les concepts afin
d'élucider les relations existantes entre
l'activité cérébrale et les
comportements. En réalité, ces questions
demeurent le Graal des neurosciences modernes. Ces
recherches vont, par exemple, de l'étude des
machineries moléculaires qui régulent les
rythmes circadiens à celles du contrôle
cognitif des informations émotionnelles.
Nous présentons deux travaux qui
éclairent les avancées obtenues en
mélangeant sélection
génétique et modifications
comportementales, ici le bâillement.
Par croisements, Jose R. Eguibar et al. ont
sélectionné deux lignées de de rats
Sprague-Dawley: une qui bâillent
spontanément à une basse fréquence
(LY) et l'autre à haute fréquence (HY).
Dans les deux lignées, les femelles
bâillent moins que les mâles,
confirmant le dimorphisme sexuel caractéristique
de ce comportement.
Il est connu que l'ocytocine réduit
l'anxiété et le stress lors des
interactions sociales et module les comportements
d'approche. Chez les rongeurs, l'ocytocine
améliore la mémoire sociale et joue un
rôle important dans l'établissement des
comportements d'affiliation et de soins maternels.
La libération d'octytocine dans le PVN est une
élément clé du déclenchement
du bâillement, non seulement après
stimulation des neurones de ce noyau hypothalamique par
l'ocytocine elle-même mais aussi par les agonistes
dompaminergiques ou les acides aminés excitateurs.
Ceci indique que la modulaion des
bâillements et les comportements
d'affiliation partagent des mécanimes
hypothalamo-hypophysaires communs.
Compte-tenu de la complexité neurobiologique
du bâillement et son intime association avec
la libération centrale d'ocytocine, il faut garder
en mémoire sa valeur de signal social et sa
capacité apaisante. Le bâillement
joue-t-il un rôle de modulation émotionnelle
lors d'interactions sociales stressantes ?
Dopamine D(2)-like agonists induce penile erection
(PE) and yawning in a variety of species, effects
that have been suggested recently to be specifically
mediated by the D(4) and D(3) receptors, respectively.
However, the exact role of each subtype (D2, D3 and D4)
of this receptor family in PE/YA is still not clearly
elucidated.
The authors recorded concomitantly PE and YA after
treatment with agonists with various levels of
selectivity for the different subtypes of D2-like
receptors. In addition, they investigated the efficacy of
antagonists with selective or preferential affinity for
each of the three receptor subtypes to prevent
apomorphine-induced PE and YA.
With regard to yawning, injection of APO
increased its incidence, as expected from previous
studies, but neither APO- nor-vehicle-injected males
showed an effect of copulation on yawning. They
infer that yawning and erection are readily
dissociable and that any changes in brain dopamine
resulting from copulating to ejaculation are not
sufficient to promote reliable changes in yawning
latency or frequency.
L'effet de la
copulation sur le bâillement
Les agonistes dopaminergiques D2 induisent
l'érection pénienne et le
bâillement chez de nombreuses espèces
d'animaux. Ces effets semblent médiés
specifiquement pas les récepteurs D4 et D3
respectivement. Néanmoins, le rôle exact de
chaque sous-type (D2,D3 et D4) de cette famille de
récepteurs liés aux érections et aux
bâillements n'est pas encore actuellement
bien élucidé.
Les auteurs ont enregistré
simultanément érections et
bâillements après avoir
injecté des agonistes de
spécificités variables pour les
différents sous types de récepteurs. En
plus, ils ont porté particulièrement leur
attention sur l'efficacité d'antagonistes
doués de sélectivité ou
d'affinité partielle pour chacun des trois
sous-types de récepteurs capables d'empêcher
l'apparition d'érections ou de
bâillements déclenchés par
l'injection d'apomorphine.
Comme des études antérieures l'avaient
montré, l'apomorphine augmente l'incidence des
bâillements mais ni l'apomorphine ni un
placebo ne montre d'effet de la copulation sur les
bâillements. Il semble donc possible de
dissocier érections et bâillements et
que les modifications de la dopamine induites par
l'éjaculation ne sont pas suffisantes pour
modifier ni la latence ni la fréquence des
bâillements
-Collins
GT, Newman AH,Woods JH et al.Yawning and hypothermia
in rats: effects of dopamine D3 and D2 agonists and
antagonists. Psychopharmacology (Berl).
2007;193(2):159-170
-Collins
GT. Newman AH, Grundt P, et al. Food restriction
alters pramipexole-induced yawning, hypothermia, and
locomotor activity in rats: Evidence for sensitization of
dopamine D2 receptor-mediated effects. JEPT
2008;325:691-697
-Collins
GT, Woods JH Narrowing in on compulsions: dopamine
receptor functions Exp Clin Psychopharmacol
2008,16(4):498-502
-Collins
GT, Truong YN, et al. Behavioral sensitization to
cocaine in rats: evidence for temporal differences in
dopamine D(3) and D (2) receptor sensitivity.
Psychopharmacology (Berl). 2011
Incongruence effects
in crossmodal emotional integration
Müller VI, Habel U, Derntl B, Schneider F,
Zilles K, Turetsky BI, Eickhoff SB.
Neuroimage
2011;54(3):2257-2266
When yawning is a
neutral stimulus !
Emotions are often encountered in a multimodal
fashion. Consequently, contextual framing by other
modalities can alter the way that an emotional facial
expression is perceived and lead to emotional conflict.
Whole brain fMRI data was collected when 35 healthy
subjects judged emotional expressions in faces while
concurrently being exposed to emotional (scream,
laughter) or neutral (yawning) sounds.
The behavioral results showed that subjects rated
fearful and neutral faces as being more fearful when
accompanied by screams than compared to yawns (and laughs
for fearful faces). Moreover, the imaging data revealed
that incongruence of emotional valence between faces and
sounds led to increased activation in the middle
cingulate cortex, right superior frontal cortex, right
supplementary motor area as well as the right
temporoparietal junction.
Against expectations no incongruence effects could be
found in the amygdala. Further analyses revealed that,
independent of emotional valence congruency, the left
amygdala was consistently activated when the information
from both modalities was emotional. If a neutral stimulus
was present in one modality and emotional in the other,
activation in the left amygdala was significantly
attenuated. These results indicate that incongruence of
emotional valence in audiovisual integration activates a
cingulate-fronto-parietal network involved in conflict
monitoring and resolution.
Furthermore in audiovisual pairing amygdala responses
seem to signal also the absence of any neutral feature
rather than only the presence of an emotionally charged
one.
Festus grammaticus, Sextus Pompeius Festus
était un grammairien latin de la fin du IIe
siècle ap. J.-C. Il avait composé, sous le
titre de De Significatione Verborum, une sorte de
dictionnaire précieux pour la connaissance des
antiquités romaines, de la langue latine et de la
mythologie.
Cet ouvrage est une sorte d'abrégé de
ce traité De Verborum Significatu de Verrius
Flaccus, qui n'est pas parvenu jusqu'à nous.
Inagaki Tomoo
Tokyo
1902-1980
Stretching Cat
Woodblock print, colours
on paper
mainly brown
pigments
1963
A distinguished Sosaku Hanga printmaker, Tomoo
Inagaki began his career as a worker in a steel company.
Influenced by contemporary poetry and art, he enrolled in
printmaking classes conducted by Koshiro Onchi and
Un-ichi Hiratsuka. He began exhibiting his original
woodcuts in 1924 and shortly thereafter left his position
at the steel company and established a commercial design
studio.
Tomoo Inagaki was forced to close his commercial art
studio during the Second World War. Up to that point his
reputation mainly rested on his woodcut and screenprint
still life images. After the end of World War II,
however, he devoted himself almost exclusively to the
imagery which made him artist of international repute --
cats. During the 1950's Inagaki was invited to exhibit
his woodcuts of cats at major print exhibitions in Paris,
Tokyo and Lugano, Switzerland. Today the woodcuts and
screenprints of Tomoo Inagaki are included in many major
public collections in Europe, Japan and America.
