2,168 research outputs found

    Delayed Imitation of Lipsmacking Gestures by Infant Rhesus Macaques (Macaca mulatta)

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    Human infants are capable of accurately matching facial gestures of an experimenter within a few hours after birth, a phenomenon called neonatal imitation. Recent studies have suggested that rather than being a simple reflexive-like behavior, infants exert active control over imitative responses and ‘provoke’ previously imitated gestures even after a delay of up to 24 h. Delayed imitation is regarded as the hallmark of a sophisticated capacity to control and flexibly engage in affective communication and has been described as an indicator of innate protoconversational readiness. However, we are not the only primates to exhibit neonatal imitation, and delayed imitation abilities may not be uniquely human. Here we report that 1-week-old infant rhesus macaques (Macaca mulatta) who show immediate imitation of a lipsmacking gesture also show delayed imitation of lipsmacking, facilitated by a tendency to refrain from lipsmacking toward a still face during baseline measurements. Individual differences in delayed imitation suggest that differentially matured cortical mechanisms may be involved, allowing some newborns macaques to actively participate in communicative exchanges from birth. Macaque infants are endowed with basic social competencies of intersubjective communication that indicate cognitive and emotional commonality between humans and macaques, which may have evolved to nurture an affective mother-infant relationship in primates

    The functional architecture of mother-infant communication, and the development of infant social expressiveness in the first two months

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    By two-three months, infants show active social expressions during face-to-face interactions. These interactions are important, as they provide the foundation for later emotional regulation and cognition, but little is known about how infant social expressiveness develops. We considered two different accounts. One emphasizes the contingency of parental responsiveness, regardless of its form; the other, the functional architecture account, emphasizes the preparedness of both infants and parents to respond in specific ways to particular forms of behaviour in their partner. We videotaped mother-infant interactions from one to nine weeks, and analysed them with a micro-analytic coding scheme. Infant social expressiveness increased through the nine-week period, particularly after 3 weeks. This development was unrelated to the extent of maternal contingent responsiveness, even to infant social expressions. By contrast, specific forms of response that mothers used preferentially for infant social expressions - mirroring, marking with a smile- predicted the increase in these infant behaviours over time. These results support a functional architecture account of the perceptual and behavioural predispositions of infants and parents that allows young infants to capitalize on relatively limited exposure to specific parental behaviours, in order to develop important social capacities

    Gravitational Waves from Gravitational Collapse

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    Gravitational wave emission from the gravitational collapse of massive stars has been studied for more than three decades. Current state of the art numerical investigations of collapse include those that use progenitors with realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non--axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with advanced ground--based and future space--based interferometric observatories.Comment: 68 pages including 13 figures; revised version accepted for publication in Living Reviews in Relativity (http://www.livingreviews.org

    Clusters of galaxies : observational properties of the diffuse radio emission

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    Clusters of galaxies, as the largest virialized systems in the Universe, are ideal laboratories to study the formation and evolution of cosmic structures...(abridged)... Most of the detailed knowledge of galaxy clusters has been obtained in recent years from the study of ICM through X-ray Astronomy. At the same time, radio observations have proved that the ICM is mixed with non-thermal components, i.e. highly relativistic particles and large-scale magnetic fields, detected through their synchrotron emission. The knowledge of the properties of these non-thermal ICM components has increased significantly, owing to sensitive radio images and to the development of theoretical models. Diffuse synchrotron radio emission in the central and peripheral cluster regions has been found in many clusters. Moreover large-scale magnetic fields appear to be present in all galaxy clusters, as derived from Rotation Measure (RM) studies. Non-thermal components are linked to the cluster X-ray properties, and to the cluster evolutionary stage, and are crucial for a comprehensive physical description of the intracluster medium. They play an important role in the cluster formation and evolution. We review here the observational properties of diffuse non-thermal sources detected in galaxy clusters: halos, relics and mini-halos. We discuss their classification and properties. We report published results up to date and obtain and discuss statistical properties. We present the properties of large-scale magnetic fields in clusters and in even larger structures: filaments connecting galaxy clusters. We summarize the current models of the origin of these cluster components, and outline the improvements that are expected in this area from future developments thanks to the new generation of radio telescopes.Comment: Accepted for the publication in The Astronomy and Astrophysics Review. 58 pages, 26 figure

    Purinergic modulation of microglial cell activation

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    Microglial cells are resident macrophages in the brain and their activation is an important part of the brain immune response and the pathology of the major CNS diseases. Microglial activation is triggered by pathological signals and is characterized by morphological changes, proliferation, phagocytosis and the secretion of various cytokines and inflammatory mediators, which could be both destructive and protective for the nervous tissue. Purines are one of the most important mediators which regulate different aspects of microglial function. They could be released to the extracellular space from neurons, astrocytes and from the microglia itself, upon physiological neuronal activity and in response to pathological stimuli and cellular damage. Microglial activation is regulated by various subtypes of nucleotide (P2X, P2Y) and adenosine (A1, A2A and A3) receptors, which control ionic conductances, membrane potential, gene transcription, the production of inflammatory mediators and cell survival. Among them, the role of P2X7 receptors is especially well delineated, but P2X4, various P2Y, A1, A2A and A3 receptors also powerfully participate in the microglial response. The pathological role of microglial purine receptors has also been demonstrated in disease models; e.g., in ischemia, sclerosis multiplex and neuropathic pain. Due to their upregulation and selective activation under pathological conditions, they provide new avenues in the treatment of neurodegenerative and neuroinflammatory illnesses

    Vicarious Learning from Human Models in Monkeys

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    We examined whether monkeys can learn by observing a human model, through vicarious learning. Two monkeys observed a human model demonstrating an object–reward association and consuming food found underneath an object. The monkeys observed human models as they solved more than 30 learning problems. For each problem, the human models made a choice between two objects, one of which concealed a piece of apple. In the test phase afterwards, the monkeys made a choice of their own. Learning was apparent from the first trial of the test phase, confirming the ability of monkeys to learn by vicarious observation of human models

    Modification of neuropathic pain sensation through microglial ATP receptors

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    Neuropathic pain that typically develops when peripheral nerves are damaged through surgery, bone compression in cancer, diabetes, or infection is a major factor causing impaired quality of life in millions of people worldwide. Recently, there has been a rapidly growing body of evidence indicating that spinal glia play a critical role in the pathogenesis of neuropathic pain. Accumulating findings also indicate that nucleotides play an important role in neuron-glia communication through P2 purinoceptors. Damaged neurons release or leak nucleotides including ATP and UTP to stimulate microglia through P2 purinoceptors expressing on microglia. It was shown in an animal model of neuropathic pain that microglial P2X4 and P2X7 receptors are crucial in pain signaling after peripheral nerve lesion. In this review, we describe the modification of neuropathic pain sensation through microglial P2X4 and P2X7, with the possibility of P2Y6 and P2Y12 involvement

    Efficacy and tolerability of α-galactosidase in treating gas-related symptoms in children: a randomized, double-blind, placebo controlled trial

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    BACKGROUND: Gas-related symptoms represent very common complaints in children. The reduction of gas production can be considered as a valuable target in controlling symptoms. α-galactosidase has been shown to reduce gas production and related symptoms in adults. To evaluate the efficacy and tolerability of α-galactosidase in the treatment of gas-related symptoms in pediatric patients. METHODS: Single center, randomized, double-blind, placebo-controlled, parallel group study performed in tertiary care setting. Fifty-two pediatric patients (32 female, age range 4–17) with chronic or recurrent gas-related symptoms were randomized to receive placebo (n = 25) or α-galactosidase (n = 27). Both treatments were given as drops or tablets, according to body weight for 2 weeks. The primary endpoint was the reduction in global distress measured by the Faces Pain Scale-Revised (FPS-R) at the end of treatment compared to baseline. Secondary endpoints were the reduction in severity and frequency of gas-related symptoms as recorded by parents and/or children. RESULTS: α-galactosidase significantly reduced global distress (p = 0.02) compared to placebo. The digestive enzyme decreased the number of days with moderate to severe bloating (p = 0.03) and the proportion of patients with flatulence (p = 0.02). No significant differences were found for abdominal spasms and abdominal distension. No adverse events were reported during treatment. CONCLUSIONS: Although larger and longer trials are needed to confirm this result, α-galactosidase seems to be a safe, well tolerated and effective treatment for gas-related symptoms in the pediatric population. TRIAL REGISTRATION: ClinicalTrials.gov, NCT0159593
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