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Concept

Douleur

Résumé

La douleur est une « expérience sensorielle et émotionnelle désagréable », une sensation subjective normalement liée à un message, un stimulus nociceptif transmis par le système nerveux. D'un point de vue biologique et évolutif, la douleur est une information permettant à la conscience de faire l'expérience de l'état de son corps pour pouvoir y répondre. On distingue principalement deux types de douleur, aiguë et chronique :

la douleur aiguë correspond à un « signal d'alarme » de l'organisme pour inciter à une réaction appropriée en cas de remise en cause de son intégrité physique, soit par un traumatisme (brûlure, plaie, choc), soit par une maladie ;
la douleur chronique, l'installation durable de la douleur, est considérée comme une maladie qui peut notamment être le signe d'un dysfonctionnement des mécanismes de sa genèse, on parle alors de douleur neurogène ou psychogène.

Cette sensation, de désagréable à insupportable, n'est pas nécessa

Source officielle

https://fr.wikipedia.org/wiki/Douleur

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Publications associées (31)

Tonic pain alters functional connectivity of the descending pain modulatory network involving amygdala, periaqueductal gray, parabrachial nucleus and anterior cingulate cortex

Anne-Christine Schmid

Introduction: Resting state functional connectivity (FC) is widely used to assess functional brain alterations in patients with chronic pain. However, reports of FC accompanying tonic pain in pain-free persons are rare. A network we term the Descending Pain Modulatory Network (DPMN) is implicated in healthy and pathologic pain modulation. Here, we evaluate the effect of tonic pain on FC of specific nodes of this network: anterior cingulate cortex (ACC), amygdala (AMYG), periaqueductal gray (PAG), and parabrachial nuclei (PBN). Methods: In 50 pain-free participants (30F), we induced tonic pain using a capsaicin-heat pain model. functional MRI measured resting BOLD signal during pain-free rest with a 32 degrees C thermode and then tonic pain where participants experienced a previously warm temperature combined with capsaicin. We evaluated FC from ACC, AMYG, PAG, and PBN with correlation of self-report pain intensity during both states. We hypothesized tonic pain would diminish FC dyads within the DPMN. Results: Of all hypothesized FC dyads, only PAG and subgenual ACC was weakly altered during pain (F = 3.34; p = 0.074; pain-free>pain d = 0.25). After pain induction sACC-PAG FC became positively correlated with pain intensity (R = 0.38; t = 2.81; p = 0.007). Right PBN-PAG FC during pain-free rest positively correlated with subsequently experienced pain (R = 0.44; t = 3.43; p = 0.001). During pain, this connection's FC was diminished (paired t=-3.17; p = 0.0026). In whole-brain analyses, during pain-free rest, FC between left AMYG and right superior parietal lobule and caudate nucleus were positively correlated with subsequent pain. During pain, FC between left AMYG and right inferior temporal gyrus negatively correlated with pain. Subsequent pain positively correlated with right AMYG FC with right claustrum; right primary visual cortex and right temporo-occipitoparietal junction Conclusion: We demonstrate sACC-PAG tonic pain FC positively correlates with experienced pain and resting right PBN-PAG FC correlates with subsequent pain and is diminished during tonic pain. Finally, we reveal PAG-and right AMYG-anchored networks which correlate with subsequently experienced pain intensity. Our findings suggest specific connectivity patterns within the DPMN at rest are associated with subsequently experienced pain and modulated by tonic pain. These nodes and their functional modulation may reveal new therapeutic targets for neuromodulation or biomarkers to guide interventions.

ACADEMIC PRESS INC ELSEVIER SCIENCE2022

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The missing social instinct

Nicole Regula Zürcher Wimmer

Smooth social interactions in everyday life rely on spontaneous understanding of emotions and intentions of others, conveyed by subtle social cues, such as gaze and facial expressions. In individuals with autism, however, who represent close to 1% of the population, this effortless and spontaneous understanding is impaired, and atypical eye contact as well as difficulties in social interaction are central to the condition. A lack of social instinct has been suggested as the essence of this neurodevelopmental disorder. In this work, I investigated configural face processing, interactions of emotions and eye gaze direction as well as empathy for pain in high- functioning young adults with autism spectrum disorders (ASD) using magnetic resonance imaging and behavioral measures. I also conducted anatomical investigations of white matter in adolescents and adults with autism to investigate structural differences underlying socio-cognitive processing. Findings showed that individuals with ASD process faces in a qualitatively similar manner as controls, namely configurally, as a unified whole. Moreover, the results showed that when participants are explicitly cued to the eye region, activation of cortical areas involved in social and emotional aspects of face processing reaches levels comparable to those observed in controls. When confronted with quick social gaze cues signaling an environmental threat, however, participants with ASD failed to show activation in areas associated with social attention, including brain regions driving eye gaze and emotion processing as well as the attribution of mental states. In contrast, affective empathy, referring to emotional contagion that has us “feeling like others” is preserved in ASD when viewing facial expressions of physical pain in others. Cognitive empathy on the other hand, which is associated with the attribution of mental states to others as well as top-down regulation of emotional arousal, seems impaired in ASD. In addition, across experiments, direct eye contact led to hyperactivation of subcortical regions suggesting hyperarousal in response to direct gaze that could underlie gaze avoidance observed in autism. Finally, we observed signs of delayed maturation in white matter tracts involved in emotional face processing in adolescents with ASD, but not in adults, which could be related to the improvements often observed in social interactions as individuals with autism enter adulthood. The studies conducted here shed light onto neural processes underlying social cognition deficits in ASD and provide clues for improving behavioral therapies.

EPFL2012

Chargement

Fetal therapies have become available for a restricted number of life-threatening clinical conditions. Harnessing tissue engineering for prenatal applications has not been widely pursued even though isolating cells from fetal and extraembryonic tissues has been routinely done for years. The objectives of this thesis were twofold: i) the development of materials based and tissue engineering based strategies to prevent iatrogenic preterm prelabour rupture of fetal membranes (iPPROM) after diagnostic or therapeutic interventions into the amniotic cavity and ii) the generation of tissue substitutes from patient derived fetal cells, which can be employed for prenatal or perinanal transplantation to restore or replace defective tissues. For the prevention of iPPROM, mussel-mimetic tissue adhesive (mussel glue) a biomaterial which was recently described to not compromise cell viability and to have good tissue sealing capability was compared to fibrin glue. In this in vivo study we assessed whether in a mid-gestational rabbit model punctured fetal membranes could be efficiently sealed with mussel glue. Mussel glue showed comparable in vivo performance to fibrin glue in sealing fetal membranes though no apparent healing of the membranes could be observed in any of the samples. The limited ability of naturally derived scaffolds to promote fetal membrane healing inspired the engineering of synthetic plugging material with specifically tailored biological and mechanical properties which could activate the cells in the amnion and induce a healing response. In this thesis the modularly designed biomimetic poly(ethylene glycol) (PEG)-based hydrogel platform (called TG-PEG from here on) was used together with fetal cells to demonstrate that upon presentation of appropriate biological cues in 3D tissue mimicking environment, mesenchymal progenitor cells from amnion can be mobilized, induced to proliferate and supported in maintaining their native extracellular matrix production, thus creating a suitable environment for healing to take place. These data provide the basis for future engineering of materials with defined mechanical and biochemical properties and the ability to present migration and proliferation inducing factors, namely PDGF, bFGF, or EGF which could be key in resolving the clinical problem of iPPROM and allowing the field of fetal surgery to move forward. Cleft palate, where the bones of the palatal halves fail to fuse properly, is one of the most common birth defects. Tissue engineering has been envisioned as a treatment option but current approaches have been limited by the lack of i) appropriate autologous cell sources and ii) structural organization and vascularization. Tissue engineering of cleft palates using of autologous amniocentesis-derived and thus ethically unproblematic fetal amniotic fluid cells (AFCs) could be done parallel to the ongoing pregnancy with living reconstruction material being ready when the child is born. We describe using TG-PEG hydrogels to first evaluate 3D osteogenic differentiation of AFCs and creation of vascular structures from AFC derived endothelial cells (enAFC) and undifferentiated AFC either in random or organized channel cocultures in vitro and in vivo. Next, these approaches were combined in an osteogenic matrix with a channel perfused with enAFC and finally the integration and functional properties of these fetal bone constructs was tested in ectopic mouse model.

EPFL2015

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Tonic pain alters functional connectivity of the descending pain modulatory network involving amygdala, periaqueductal gray, parabrachial nucleus and anterior cingulate cortex

Anne-Christine Schmid

ACADEMIC PRESS INC ELSEVIER SCIENCE2022

EPFL2015

The missing social instinct

Nicole Regula Zürcher Wimmer

EPFL2012