465 research outputs found

    La rocaille en octobre

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    On the assumptions that we make about the world around us : a conceptual framework for feature transformation effects

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    Various phenomena such as halo effects, spontaneous trait inferences, and evaluative conditioning have in common that assumptions about object features (e.g., whether a person is intelligent or likeable) are influenced by other object features (e.g., whether that person is attractive or co-occurs with other liked persons). Surprisingly, these phenomena have rarely been related to each other, most likely because different phenomena are described using different terms. To overcome this barrier, we put forward a conceptual framework that can be used to describe a wide range of these phenomena. After introducing the four core concepts of the framework, we illustrate how it can be applied to various phenomena. Doing so helps to reveal similarities and differences between those phenomena, thus improving communication and promoting interactions between different areas of research. Finally, we illustrate the generative power of the framework by discussing some of the new research questions that it highlights

    Genetic manipulation of adult-born hippocampal neurons rescues memory in a mouse model of Alzheimer's disease

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    Richetin et al. demonstrate that retroviral expression of the transcription factor NeuroD1 in neural progenitor cells of the adult mouse hippocampus promotes differentiation, maturation and synaptic integration of newborn granule cells in vivo. When applied to a mouse model of Alzheimer's disease, the gene-targeting strategy abolishes hippocampus-dependent memory deficit

    Sex Differences in the Perceived Dominance and Prestige of Women With and Without Cosmetics

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    Human social status has long been of interest to evolutionary and social psychologists. The question of who gets to control resources and be a leader has garnered a lot of attention from these and other fields, and this thesis examines evidence for there being two different mechanisms of achieving high status, and their correlates. The mechanisms are 1) Dominance: being aggressive, manipulative and forcing others to follow you, and 2) Prestige: possessing qualities which make others freely follow you. Chapter 1 is an introductory chapter in which I explain selection pressures, group formation, and the need for social hierarchies; I then describe the two proposed methods of attaining social status and how facial characteristics can give clues as to an individual’s social status. In Chapter 2, my first experimental chapter, I examined how faces created to appear either high in dominance or high in prestige were judged with respect to those traits as well as personality characteristics. Taking this further, in Chapter 3, I looked at how natural variation in real faces would reflect differences in other- and self-perceived ratings of dominance and prestige. Chapter 4 served to examine whether, given a set of words related to social status, I would find differences in what words were placed into dominant or prestige categories. Findings within these chapters are consistent with dominance and prestige being separable methods of attaining high status, from differences in facial appearance (Chapter 2 and 3), to personality characteristics (Chapter 2), to word usage (Chapter 4). Once I had established that these were two distinct routes to achieving high status, I chose to focus on dominance in Chapter 5 and explored the conceptual relationships between dominance and facial expressions. I found that manipulating perceptions of dominance affected how intense expressions of anger, sadness, and fear were perceived (Chapter 5). As there has been a paucity of research in the area of women’s social status, in Chapter 6, I went on to explore what effects cosmetics use in women would have on their perceived social status. I found differences in how men and women perceived women wearing cosmetics, which again points to a distinction between dominance and prestige. My thesis then presents a broad view of the two different mechanisms for attaining high status. Using new methods not otherwise used in exploring dominance and prestige I was able to explore correlates and indicators, as well as perceptions of both strategies. These findings will allow us to determine who might be capable of attaining social status, which of the two methods they might use, as well as what implicit associations we hold about each. They will also open doors for future research into the two strategies, and even help interpret previous research, as many previous studies simply relate to high status and do not distinguish between dominance and prestige

    A Model of Trust Processes in Borderline Personality Disorder: A Systematic Review

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    Purpose of Review: Unstable relationships are a core feature of borderline personality disorder (BPD). Impairments in trust processes (i.e., appraisal and learning regarding others’ trustworthiness) can subserve interpersonal problems associated with BPD, but the determinants, mechanisms, consequences, and variations in trust impairments among individuals with BPD remain poorly characterized. Thus, a better understanding of such impairments could help target interventions that address the interpersonal problems of individuals with BPD beyond emotion dysregulation, impulsivity, and aggression. Recent Findings: We conducted a pre-registered systematic review of empirical studies on trust processes and BPD features (k = 29). Results are organized around a heuristic model of trust processes in BPD comprising the following stages: developmental factors, prior beliefs and dispositions, situation perception, emotional states, trust appraisal, behavioral manifestations, and trust learning. Summary: Based on the synthesis of the findings, we recommended directions for future research and clinical assessment and intervention, such as managing trust during the early stages of therapy and considering improvements in trust processes as a central mechanism of change in treating individuals with BPD

    PCT and beyond: toward a computational framework for ‘intelligent’ communicative systems

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    Recent years have witnessed increasing interest in ‘intelligent’ autonomous machines such as robots. However, there is a long way to go before autonomous systems reach the level of capabilities required for even the simplest of tasks involving human-robot interaction - especially if it involves communicative behavior such as speech and language. The field of Artificial Intelligence (AI) has made great strides in these areas, and has graduated from high-level rule-based paradigms to embodied architectures whose operations are grounded in real physical environments. What is still missing, however, is an overarching theory of intelligent communicative behavior that informs system-level design decisions. This chapter introduces a framework that extends the principles of Perceptual Control Theory (PCT) toward a remarkably symmetric architecture for a needs-driven communicative agent. It is concluded that, if behavior is the control of perception (the central tenet of PCT), then perception (for communicative agents) is the simulation of behavior

    AAV5-miHTT gene therapy demonstrates suppression of mutant huntingtin aggregation and neuronal dysfunction in a rat model of Huntington's disease.

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    Huntington's disease (HD) is a fatal progressive neurodegenerative disorder caused by a mutation in the huntingtin (HTT) gene. To date, there is no treatment to halt or reverse the course of HD. Lowering of either total or only the mutant HTT expression is expected to have therapeutic benefit. This can be achieved by engineered micro (mi)RNAs targeting HTT transcripts and delivered by an adeno-associated viral (AAV) vector. We have previously showed a miHTT construct to induce total HTT knock-down in Hu128/21 HD mice, while miSNP50T and miSNP67T constructs induced allele-selective HTT knock-down in vitro. In the current preclinical study, the mechanistic efficacy and gene specificity of these selected constructs delivered by an AAV serotype 5 (AAV5) vector was addressed using an acute HD rat model. Our data demonstrated suppression of mutant HTT messenger RNA, which almost completely prevented mutant HTT aggregate formation, and ultimately resulted in suppression of DARPP-32-associated neuronal dysfunction. The AAV5-miHTT construct was found to be the most efficient, although AAV5-miSNP50T demonstrated the anticipated mutant HTT allele selectivity and no passenger strand expression. Ultimately, AAV5-delivered-miRNA-mediated HTT lowering did not cause activation of microglia or astrocytes suggesting no immune response to the AAV5 vector or therapeutic precursor sequences. These preclinical results suggest that using gene therapy to knock-down HTT may provide important therapeutic benefit for HD patients and raised no safety concerns, which supports our ongoing efforts for the development of an RNA interference-based gene therapy product for HD

    Structural filtering of greylevel images from principal curvatures analysis

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    A new digital images smoothing method, named structural filtering, is proposed which uses a 3D representation of greylevel images (z =f(x, y)) and their description with principal curvature features . The organization of the horizontal projections of the principal curvature directions is analysed in order to determine a direction which well indicates the orientation of the local structure of the image . If such a direction is found, filtering is performed by averaging with a directional convolution mask according to that direction, if not, a classical 3 x 3 mean filter is used . This filter permits on one hand to cut off the noise while preserving step edges and ridges, on the other hand, it allows the schematization of the principal structures of the image . This last capability has never being obtained before with classical filters . Experimental results are shown through real images of textures made of complex structures and compared with those obtained with a 3 x 3 median filter . These results are then validated by primitive extraction using classical skeletonization or edge detection algorithms . At last, the behavior of the filter in function of the iteration number is analysed in order to show up its good convergence property .Une nouvelle méthode de filtrage d'images digitalisées, appelée filtrage structurel, est proposée . Elle utilise une repésentation tridimensionnelle des images à niveaux de gris (x, y, z=f(x, y)) et leur description à partir des courbures principales calculées en chaque point de la surface . L'organisation des projections horizontales des courbures principales est analysée en vue de déterminer une direction rendant compte de l'orientation locale de la structure au point considéré . Si une direction de filtrage peut être déterminée, elle sert de support à un masque moyenneur directionnel de convolution, sinon un masque moyenneur classique bidimensionnel de taille 3 x 3 est appliqué . Ce filtre permet ainsi non seulement d'éliminer le bruit en préservant les lignes de transition et de crête de l'image, mais aussi, il autorise la schématisation des structures présentes dans l'image originale, cette dernière propriété n'ayant jamais été jusqu'alors obtenue avec des méthodes de filtrage classiques . Des résultats expérimentaux sont montrés à partir d'images réelles de texture composées de structures complexes en les comparant avec ceux obtenus à l'aide d'un filtre médian 3 x 3 . Ces résultats sont ensuite validés en effectuant une extraction de primitives telles que les lignes de squelette ou de contour . Enfin, une analyse du comportement du filtre en fonction du nombre d'itérations est faite qui met en valeur une propriété de bonne convergence

    The Neurogenesis Actuator and NR2B/NMDA Receptor Antagonist Ro25-6981 Consistently Improves Spatial Memory Retraining Via Brain Region-Specific Gene Expression

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    NR2B-containing NMDA (NR2B/NMDA) receptors are important in controlling neurogenesis and are involved in generating spatial memory. Ro25-6981 is a selective antagonist at these receptors and actuates neurogenesis and spatial memory. Inter-structural neuroanatomical profiles of gene expression regulating adult neurogenesis and neuroapoptosis require examination in the context of memory retrieval and reversal learning. The aim was to investigate spatial memory retrieval and reversal learning in relation to gene expression-linked neurogenetic processes following blockade of NR2B/NMDA receptors by Ro25-6981. Rats were trained in Morris water maze (MWM) platform location for 5 days. Ro25-6981 was administered (protocol days 6–7) followed by retraining (days 15–18 or 29–32). Platform location was tested (on days 19 or 33) then post-mortem brain tissue sampling (on days 20 or 34). The expression of three genes known to regulate cell proliferation (S100a6), differentiation (Ascl1), and apoptosis (Casp-3) were concomitantly evaluated in the hippocampus, prefrontal cortex, and cerebellum in relation to the MWM performance protocol. Following initial training, Ro25-6981 enhanced visuospatial memory retrieval performance during further retraining (protocol days 29–32) but did not influence visuospatial reversal learning (day 33). Hippocampal Ascl1 and Casp-3 expressions were correspondingly increased and decreased while cerebellar S100a6 and Casp-3 activities were decreased and increased respectively 27 days after Ro25-6981 treatment. Chronological analysis indicated a possible involvement of new mature neurons in the reconfiguration of memory processes. This was attended by behavioral/gene correlations which revealed direct links between spatial memory retrieval enhancement and modified gene activity induced by NR2B/NMDA receptor blockade and upregulation

    Astrocytes' Contribution to Adult Neurogenesis in Physiology and Alzheimer's Disease.

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    Adult neurogenesis is one of the most drastic forms of brain plasticity in adulthood and there is a growing body of evidence showing that, in the hippocampus, this process contributes to mechanisms of memory as well as depression. Interestingly, adult neurogenesis is tightly regulated by the neurogenic niche, which provides a structural and molecular scaffold for stem cell proliferation and the differentiation and functional integration of new neurons. In this review, we highlight the role of astrocytes in the regulation of adult neurogenesis in the context of cognitive function. We also discuss how the changes in astrocytes function may dysregulate adult neurogenesis and contribute to cognitive impairment in the context of Alzheimer's disease
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