Drawing firmer conclusions: autistic children show no evidence of a local processing bias in a controlled copying task

Drawing tasks are frequently used to test competing theories of visuospatial skills in autism. Yet, methodological differences between studies have led to inconsistent findings. To distinguish between accounts based on local bias or global deficit, we present a simple task that has previously revealed dissociable local/global impairments in neuropsychological patients. Autistic and typical children copied corner elements, arranged in a square configuration. Grouping cues were manipulated to test whether global properties affected the accuracy of reproduction. All children were similarly affected by these manipulations. There was no group difference in the reproduction of local elements, although global accuracy was negatively related to better local processing for autistic children. These data speak against influential theories of visuospatial differences in autism

Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe

Evaluation externe de l'institut d'économie rurale. Programme ressources forestières du 5 au 19 mars 1997

Dans le cadre du Plan Stratégique de la Recherche Agronomique au Mali et des Programmes de l'Institut d'Economie Rurale, il est prévu une évalution des programmes de recherche à mi-parcours, après trois ans. Après une diagnostic, le consultants présentent leurs recommandations, regroupées en 14 suggestions. Ces dernières concernent principalement la programmation, la formation des chercheurs et l'animation scientifique, la valorisation des résultats, le fonctionnement de la structure. Des recommandations thématiques sont également émises autour de quatre thèmes principau

Influence of visual motion on reversal speeds in an ambiguous Necker cube experiment: an eye-tracking study

International audienceMultistability is the oscillation between different perceptual states under constant physical stimulus. Although either or both bottom-up and top-down processing can explain such oscillations (Leopold & Logothetis, 1999), we focus here on bottom-up information processing in which perceptual reversal is associated with passive neural adaptation and noise, early in visual processing (Kornmeier & Bach, 2005). Objectives. We had focused on bottom-up factors governed by low-level visual features, to study the effects of adaptation and noise on reversal speed. Methods. Inspired by the experimental design in (Blake, Sobel & Geloy, 2003) we manipulate the adaptation level by moving the stimulus following a smooth Lissajous trajectory (LJ). We expected a decrease in reversal speed compared to a fixed stimulus (FX), serving as our control condition. Ocular noise was controlled through pseudo-random movements of the stimulus (random walk, RW). Under this “random walk” condition, an increased reversal speed was expected by assuming a higher noise level. The three conditions were randomly sequenced. Participants were instructed to stare at a central point during the stimulus presentation (Necker cube) at the screen centre, and to report their perceptual changes by keypress. After removing outliers, data (eye movements and behavioural responses) from sixteen participants were analysed. Results. The hypothesis concerning the ocular noise was supported by a significant increase of reversal speed (RW > FX) as a consequence of a continuous spatial jitter of the retinal image. However, we also found LJ > FX, in contrast to our initial hypothesis following (Blake, Sobel & Geloy, 2003). Upon further inspection of eye fixational movements during the “Lissajous” condition, we observed a systematic smooth gaze pursuit following the centre of gravity of the moving stimulus, increasing retinal image stability. Through this stabilisation, adaptation could set in earlier, provoking faster reversals

Motion on a Necker cube leads to micro-pursuit-like eye movements and affects the dynamics of bistability

International audienceMultistable perception occurs when a single, but ambiguous stimulus drives perceptual alternations. Understanding its mechanisms has a direct impact on perceptual inference and decision making. A model proposed by Shpiro and colleagues explains the dynamics of bistable perception by neural adaptation and driving noise. The action of adaptation and noise on competing neuronal populations—each encoding a perceptual representation—results in perceptual reversals.Goal. To test effects of noise and adaptation on perceptual reversal speed.Methods. We manipulate noise and adaptation using predictability of the retinal projection of the stimulus. A Necker cube was presented to 16 observers instructed to gaze at a central fixation cross while reporting their perceptual changes by key press. The stimulus followed either a smooth, predictable motion; a pseudo-random motion; or no motion at all (control). Our hypotheses predicted higher (lower) reversal speeds for low (high) predictable motion w.r.t. no motion.Results. Key press analysis validated our hypothesis for unpredictable motion, but not for predictable motion. We explain the latter by quantifying correlations between stimulus and gaze positions. This shows that observers executed micro-pursuit-like movements under predictable stimulus motion, thereby increasing the effect of adaptation on reversal speed w.r.t. our hypothesis

Quantifying pursuit movements through measures of spatio-temporal similarity

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A multistable gravitational potential approach to fixational eye movements

International audienceMultistable perception occurs when a single but ambiguous stimulus drives perceptual alternations. Understanding its mechanisms has a direct impact on perceptual inference and decision making. A model proposed by Shpiro and colleagues explains the dynamics of bistable perception through neural adaptation and driving noise. Eye movement data from an experiment, in which participants observed a moving Necker cube in a continuous viewing paradigm, revealed that micropursuit-like fixational eye movements (FEM) can occur; a type of movements not accounted for in current FEM models. Our analysis also suggested that FEM can have an influence on adaptation and noise (Parisot et al., ECEM'17, Hicheur et al., JOV'13). Therefore, we propose a model that could help predict and explain away interactions between FEM and multistablity dynamics. It is based on gravity potential fields where their distortion by attractors allows the generation of multistability for the position of the gaze w.r.t. the different attractors. Adaptation and noise can be used as mechanisms to simulate the impact of stimulus motion and the task on FEM. Perceptual memory and/or anticipation of stimulus motion can be taken into account through potential field distortion. The model is able to generate drift, tremor, microsaccades, and micropursuits, showing that stimulus motion can influence the trajectories of drifts and microsaccades. Using attractors provides a link between models of multistable perception and FEM based on the mechanisms of noise and adaptation; making it possible to find correlations between perceptual and oculomotor dynamics

Micro-pursuit: A class of fixational eye movements correlating with smooth, predictable, small-scale target trajectories

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Multimodal Approach to Remove Ocular Artifacts from EEG Signals Using Multiple Measurement Vectors

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Dietary n-3 PUFA May Attenuate Experimental Colitis

International audienceBackground. Inflammatory bowel diseases (IBD) occurred in genetically predisposed people exposed to environmental triggers. Diet has long been suspected to contribute to the development of IBD. Supplementation with n-3 polyunsaturated fatty acids (PUFA) protects against intestinal inflammation in rodent models while clinical trials showed no benefits. We hypothesized that intervention timing is crucial and dietary fatty acid pattern may influence intestinal environment to modify inflammation genesis. The aim of this study was to evaluate the dietary effect of PUFA composition on intestinal inflammation. Methods. Animals received diet varying in their PUFA composition for four weeks before TNBS-induced colitis. Colon inflammatory markers and gut barrier function parameters were assessed. Inflammatory pathway PCR arrays were determined. Results. n-3 diet significantly decreased colon iNOS, COX-2 expression, IL-6 production, and LTB4 production but tended to decrease colon TNFα production () compared to control diet. Tight junction protein (claudin-1, occludin) expressions and MUC2 and TFF3 mRNA levels were not different among groups. n-9 diet also decreased colon IL-6 production (). Conclusions. Dietary n-3 PUFA influence colitis development by attenuating inflammatory markers. Further research is required to better define dietary advice with a scientific rationale