Extracting non-linear integrate-and-fire models from experimental data using dynamic I–V curves

The dynamic I–V curve method was recently introduced for the efficient experimental generation of reduced neuron models. The method extracts the response properties of a neuron while it is subject to a naturalistic stimulus that mimics in vivo-like fluctuating synaptic drive. The resulting history-dependent, transmembrane current is then projected onto a one-dimensional current–voltage relation that provides the basis for a tractable non-linear integrate-and-fire model. An attractive feature of the method is that it can be used in spike-triggered mode to quantify the distinct patterns of post-spike refractoriness seen in different classes of cortical neuron. The method is first illustrated using a conductance-based model and is then applied experimentally to generate reduced models of cortical layer-5 pyramidal cells and interneurons, in injected-current and injected- conductance protocols. The resulting low-dimensional neuron models—of the refractory exponential integrate-and-fire type—provide highly accurate predictions for spike-times. The method therefore provides a useful tool for the construction of tractable models and rapid experimental classification of cortical neurons

Hypovitaminosis D is associated with depression and anxiety in schizophrenia: results from the national FACE-SZ cohort. Running title: hypovitaminosis D, depression and anxiety in schizophrenia

International audienceBackground. Guidelines have been edited for the treatment of schizophrenia (SZ) and bipola

Diabète insulino-dépendant et parodontologie

AIX-MARSEILLE2-BU Méd/Odontol. (130552103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

PILINA: investigating the use of precious hues on Greek figurines

International audienceThe Louvre's Department of Greek, Etruscan, and Roman Antiquities houses one of the world's richest collections of terracotta figurines. For more than twenty years, in-depth studies have been carried out on ancient materials and techniques through scientific researches (clay and polychromy analyses) as well as conservation campaigns, linked to various exhibitions or reinstallation of the collection. Recently, the research project “PilinA. Ancient craftsmanship of color on clay figurines in the Greek world (IVth c. BC-Ist c. AD)”, funded by the LabEx Patrima (Foundation for Cultural Heritage Sciences) and led by the C2RMF and the Louvre, has brought forth new results. We now have a more precise understanding of the nature of certain dies and pigments, and we can better appreciate to which extant the polychrome ornamentation of the figurines compares with other artistic productions, especially painting, in the blending of pigments and superimposing of paint layers, in the use of chiaroscuro and the search for radiance through the use of metal leaf (gold and tin). The study has also shed light on the practice of redoing surface treatments already in Antiquity, through several cases of ancient repainting and exceptionally regilding

Conscious Cogn

This study examined whether and how emotional hypnotic suggestions modulate the visual recognition of negative words. We investigated the influence of hypnotic suggestions aimed at modifying emotional reactivity on the arousal effect in negative words. High and low suggestible individuals performed a go/no-go lexical decision task in three intra-individual conditions: with a suggestion to increase emotional reactivity, with a suggestion to decrease emotional reactivity and without hypnotic suggestion. Results showed that hypnotic suggestions modulated the arousal facilitation effect differently depending on the level of suggestibility of the participants. In high suggestible individuals, response times for low-arousal negative words varied oppositely according to the suggestion administered, while no modulations were retrieved for high-arousal ones. In contrast, no suggestion effects were found for low suggestible participants. Altogether, these findings suggest a higher influence of hypnotic suggestions on emotional words that require longer processing times in high suggestible individuals

Elastic Response of Cementitious Gels to Polycation Addition

The high compressive strength of cementitious materials stems from the creation of a percolated network of calcium silicate hydrate (C–S–H) nanoparticles glued together by strong Ca²⁺–Ca²⁺ correlation forces. Although strong, the ion correlation force is short range and yields poor elastic properties (elastic limit and resilience). Here, the use of polycations to partially replace Ca²⁺ counterions and enhance the resilience of cementitious materials is reported. Adsorption isotherms, electrophoretic mobility, as well as small angle X-ray scattering and dynamic rheometry measurements, are performed on C–S–H gels, used as nonreactive models of cementitious systems, in the presence of different linear and branched polycations for various electrostatic coupling, that is, surface charge densities (pH) and Ca²⁺ concentrations. The critical strain of the C–S–H gels was found to be improved by up to 1 order of magnitude as a result of bridging forces. At high electrostatic coupling (real cement conditions), only branched polycations are found to improve the deformation at the elastic limit. The results were corroborated by Monte Carlo simulations

Contribution from SEM Studies in the Understanding of Degradation Mechanisms of Copper Green Pigments from the Louvre Museum’s 21st Dynasty Egyptian Coffins

M&M Student Scholar Award – Sponsored by the Microanalysis SocietyInternational audienceThe 21st Egyptian Dynasty marks a big change in funeral practices. Decorations with Gods’ representations and magic formulas to help the deceased in his journey to afterlife are no longer on walls but directly on the coffin itself; which acts as an entire grave. Coffins were stored in long corridors, resembling mass graves. Egyptian Yellow Coffins are therefore a very specific production only found in the Theban area and reserved for the priests and priestesses of the Amun Temple. The study of these objects, a part of the Vatican Coffin Project, has as a main goal to identify all the materials used in order to determine the manufacturing process. A global view of this characteristic production will allow us to isolate and maybe even identify specific workshops. For this purpose a multiscale and multispectral methodology for analysis has been developed at the Centre de Recherche et de Restauration des Musées de France. In cultural heritage studies analysis are done in two steps: in-situ ones and those done on micro-samples which are micro-flakes, having a size of less 1mm². Each sample is performed to answer a precise question about the object. As an invasive procedure, very few are done. They are then unique and also very fragile. A dozen funerary sets from the Egyptian Antiquities Department of the Louvre Museum are under study. SEM imaging and SEM-EDS analysis have proved to be very helpful for the chemical characterization and also the identification of degradation mechanisms of green pigments

Les pigments verts en Égypte au début de la Troisième Période intermédiaire : de l’objet à l’artisan

Quelle que soit la période, quel que soit le support, le vert est l’une des cinq couleurs prédominantes de la palette de l’artisan égyptien avec le blanc, le jaune, le rouge et le bleu. Parmi toutes ces teintes, le vert fut celle qui contenta le moins les peintres égyptiens, lesquels n’ont eu de cesse d’expérimenter de nouveaux matériaux, tant naturels que synthétiques, comme en témoignent les pigments verts employés sur les cercueils à fond jaune de la XXIe dynastie (1069-945 av. J.-C.). Cet article se propose de montrer, par l’étude des couches picturales vertes d’un corpus composé de dix ensembles funéraires des collections du département des Antiquités égyptiennes du musée du Louvre, comment l’approche analytique renseigne sur les pratiques artisanales d’une époque, pratiques pouvant être rattachées à des signatures matérielles d’ateliers de production.Whatever the period or support, green was one of the five predominant colours in the Egyptian craftsman’s palette, alongside white, yellow, red and blue. Out of all these shades, green was the one which satisfied Egyptian painters the least; they constantly experimented with new materials – both natural and synthetic – as is attested by the green pigments used on the coffins with a yellow base dating from the 21st Dynasty (1069-945 BC). Through the study of the layers of green paint on a group of ten funerary ensembles in the Louvre’s collection of Egyptian Antiquities, this article proposes to show how an analytical approach provides information about the practices of artisans in a given period, practices that can be linked to specific production workshops

Structure and yielding of colloidal silica gels varying the range of interparticle interactions

International audienc