Etude de l'influence des disparités horizontales et verticales sur la perception de la profondeur en champ visuel périphérique

The wearing of ophthalmic lenses creates a change of the binocular disparity pattern naturally present in the visual scene. These changes can modify depth perception, especially in peripheral vision. The identification of continuous variations of horizontal disparities induced by ophthalmic lenses led to study continuous patterns of horizontal disparity. This study showed that detection of depth deformation depended on horizontal disparity gradient and on the eccentricity at the beginning of disparity variation. Moreover, the visual system seems to be more sensitive to uncrossed disparity than crossed disparity. Horizontal disparities were then combined with vertical disparities, computed from 3D shapes from horizontal disparities, so as to be congruent or in conflict, or in differente depth planes. Vertical disparity can modify the sensitivity to horizontal disparity gradient, depending on the depth signs of horizontal and vertical disparities relative to the fixation plane. The horizontal and vertical disparities would have a specific role in depth perception all over the visual field: horizontal disparity, locally processed, gives the 3D shape; vertical disparity, globally processed, estimates the absolute distance relative to the fixation plane.L'apposition de verres ophtalmiques devant les yeux engendre une modification de la distribution des disparités binoculaires existant naturellement dans les scènes visuelles, ces modifications peuvent avoir des répercussions sur la perception du relief et de la profondeur, notamment en vision périphérique. La mise en évidence de variations continues des disparités horizontales introduites par les verres ophtalmiques a conduit à étudier des patterns de disparités horizontales continues. Cette étude a montré l'importance du gradient de disparité horizontale et de son excentricité d'origine, dans la détection de déformation en profondeur. De plus, la sensibilité pour les disparités homonymes semble plus fine que pour les disparités croisées. Les disparités horizontales sont ensuite combinées avec des disparités verticales, calculées à partir des formes tridimensionnelles des disparités horizontales, de façon congruentes ou en conflit, ou dans des plans de profondeur différente. Les disparités verticales peuvent modifier la sensibilité aux gradients de disparité horizontale, selon les signes des disparités horizontales et verticales par rapport au plan de fixation. Les disparités horizontales et verticales ont donc chacune un rôle dans la perception de la profondeur sur l'ensemble du champ visuel : les disparités horizontales, traitées localement, définissent la forme tridimensionnelle ; les disparités verticales, traitées globalement, indiquent au système visuel la distance en profondeur par rapport au plan de fixation

Etude de l'influence des disparités horizontales et verticales sur la perception de la profondeur en champ visuel périphérique

L apposition de verres ophtalmiques devant les yeux engendre une modification de la distribution des disparités binoculaires existant naturellement dans les scènes visuelles, ces modifications peuvent avoir des répercussions sur la perception du relief et de la profondeur, notamment en vision périphérique. La mise en évidence de variations continues des disparités horizontales introduites par les verres ophtalmiques a conduit à étudier des patterns de disparités horizontales continues. Cette étude a montré l importance du gradient de disparité horizontale et de son excentricité d origine, dans la détection de déformation en profondeur. De plus, la sensibilité pour les disparités homonymes semble plus fine que pour les disparités croisées. Les disparités horizontales sont ensuite combinées avec des disparités verticales, calculées à partir des formes tridimensionnelles des disparités horizontales, de façon congruentes ou en conflit, ou dans des plans de profondeur différente. Les disparités verticales peuvent modifier la sensibilité aux gradients de disparité horizontale, selon les signes des disparités horizontales et verticales par rapport au plan de fixation. Les disparités horizontales et verticales ont donc chacune un rôle dans la perception de la profondeur sur l ensemble du champ visuel : les disparités horizontales, traitées localement dans le champ visuel, définissent la forme tridimensionnelle ; les disparités verticales, traitées globalement, indiquent au système visuel la distance en profondeur par rapport au plan de fixationPARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Large Benefit from Simple Things: High-Dose Vitamin A Improves RBP4-Related Retinal Dystrophy

Inherited retinal diseases (IRD) are a group of heterogeneous disorders, most of which lead to blindness with limited therapeutic options. Pathogenic variants in RBP4, coding for a major blood carrier of retinol, retinol-binding protein 4, are responsible for a peculiar form of IRD. The aim of this study was to investigate if retinal function of an RBP4-related IRD patient can be improved by retinol administration. Our patient presented a peculiar white-dot retinopathy, reminiscent of vitamin A deficient retinopathy. Using a customized next generation sequencing (NGS) IRD panel we discovered a novel loss-of-function homozygous pathogenic variant in RBP4: c.255G >A, p.(Trp85*). Western blotting revealed the absence of RBP4 protein in the patient’s serum. Blood retinol levels were undetectable. The patient was put on a high-dose oral retinol regimen (50,000 UI twice a week). Subjective symptoms and retinal function markedly and sustainably improved at 5-months and 1-year follow-up. Here we show that this novel IRD case can be treated by oral retinol administration

Hepatocellular Carcinoma Emergence in Diabetic Mice with Non-Alcoholic Steatohepatitis Depends on Diet and Is Delayed in Liver Exhibiting an Active Immune Response

International audienceThe increase of the sedentary lifestyle and high-calorie diet have modified the etiological landscape of hepatocellular carcinoma (HCC), with a recrudescence of non-alcoholic fatty liver disease (NAFLD), especially in Western countries. The purpose of our study was to evaluate the impact of high-fat diet feeding on non-alcoholic steatohepatitis (NASH) establishment and HCC development. Streptozotocin-induced diabetic male mice were fed with high-fat-high-cholesterol diet (HFHCD) or high-fat-high-sugar diet (HFHSD) from 1 to 16 weeks. Even if liver tumors appear regardless of the high-fat diet, two distinct physiopathological patterns were evidenced, with much more severe NASH hallmarks (liver injury, inflammation and fibrosis) in diabetic mice fed with HFHCD. The mild hepatic injury, weak inflammation and fibrosis observed in HFHSD were interestingly associated with earlier emergence of more numerous liver tumors. When activated helper and cytotoxic T cells, detected by flow cytometry, infiltrated the liver of HFHCD-fed diabetic mice, a delay in the appearance of tumor nodules and a limitation of their numbers were observed, suggesting that the immune activities partly controlled tumor emergence. These data highlighted two different mouse models of HCC progression in diabetic mice depending on diet, which could be useful to evaluate new therapeutic approaches for HCC by targeting the immune response

Exploration des imprégnations atmosphériques: Billet du chantier « Imprégnations atmosphériques » de l'ANR Sensibilia

Publié sur le Carnet du programme de recherche Sensibilia. Des approches sensibles pour penser les transformations des milieux de vie.Le chantier « Imprégnations atmosphériques » propose une exploration des mondes de l’air et des atmosphères de vie. Il s’intéresse aux transformations ordinaires des sensibilités à l’air, par l’air et pour l’air. Loin d’aborder le domaine de l’aérien au singulier, de manière par trop générale et générique, ce chantier se rapporte bien plutôt à des airs pluriels et en contexte, en prêtant attention à leurs qualités, à leurs conditions et à leurs effets. Le pari de ce chantier est de travailler sur l’expérience ordinaire, partagée et diffuse de l’air, en reconnaissant son caractère vital et sa permanence essentielle, tout en cherchant à mettre à jour ses singularités et ses variabilités selon les lieux, les situations, les climats, les écologies locales. Un des enjeux est alors de savoir comment documenter et activer un tel domaine qui se donne généralement comme allant de soi, relevant plutôt de l’ordre de l’évidence et ne se prêtant pas souvent à une attention particulière

Retinal Phenotype of Patients with <i>CLRN1</i>-Associated Usher 3A Syndrome in French Light4Deaf Cohort

International audiencePURPOSE. Biallelic variants in CLRN1 are responsible for Usher syndrome 3A and nonsyndromic rod-cone dystrophy (RCD). Retinal findings in Usher syndrome 3A have not been well defined. We report the detailed phenotypic description of RCD associated with CLRN1 variants in a prospective cohort

PHENOTYPIC CHARACTERISTICS OF ROD–CONE DYSTROPHY ASSOCIATED WITH MYO7A MUTATIONS IN A LARGE FRENCH COHORT

International audiencePurpose: To document the rod-cone dystrophy phenotype of patients with Usher syndrome type 1 (USH1) harboring MYO7A mutations.Methods: Retrospective cohort study of 53 patients (42 families) with biallelic MYO7A mutations who underwent comprehensive examination, including functional visual tests and multimodal retinal imaging. Genetic analysis was performed either using a multiplex amplicon panel or through direct sequencing. Data were analyzed with IBM SPSS Statistics software v. 21.0.Results: Fifty different genetic variations including 4 novel were identified. Most patients showed a typical rod-cone dystrophy phenotype, with best-corrected visual acuity and central visual field deteriorating linearly with age. At age 29, binocular visual field demonstrated an average preservation of 50 central degrees, constricting by 50% within 5 years. Structural changes based on spectral domain optical coherence tomography, short wavelength autofluorescence, and near-infrared autofluorescence measurements did not however correlate with age. Our study revealed a higher percentage of epiretinal membranes and cystoid macular edema in patients with MYO7A mutations compared with rod-cone dystrophy patients with other mutations. Subgroup analyses did not reveal substantial genotype-phenotype correlations.Conclusion: To the best of our knowledge, this is the largest French cohort of patients with MYO7A mutations reported to date. Functional visual characteristics of this subset of patients followed a linear decline as in other typical rod-cone dystrophy, but structural changes were variable indicating the need for a case-by-case evaluation for prognostic prediction and choice of potential therapies

Identification of mutations in TMEM5 and ISPD as a cause of severe cobblestone lissencephaly.

International audienceCobblestone lissencephaly is a peculiar brain malformation with characteristic radiological anomalies. It is defined as cortical dysplasia that results when neuroglial overmigration into the arachnoid space forms an extracortical layer that produces agyria and/or a "cobblestone" brain surface and ventricular enlargement. Cobblestone lissencephaly is pathognomonic of a continuum of autosomal-recessive diseases characterized by cerebral, ocular, and muscular deficits. These include Walker-Warburg syndrome, muscle-eye-brain disease, and Fukuyama muscular dystrophy. Mutations in POMT1, POMT2, POMGNT1, LARGE, FKTN, and FKRP identified these diseases as alpha-dystroglycanopathies. Our exhaustive screening of these six genes, in a cohort of 90 fetal cases, led to the identification of a mutation in only 53% of the families, suggesting that other genes might also be involved. We therefore decided to perform a genome-wide study in two multiplex families. This allowed us to identify two additional genes: TMEM5 and ISPD. Because TMEM has a glycosyltransferase domain and ISPD has an isoprenoid synthase domain characteristic of nucleotide diP-sugar transferases, these two proteins are thought to be involved in the glycosylation of dystroglycan. Further screening of 40 families with cobblestone lissencephaly identified nonsense and frameshift mutations in another four unrelated cases for each gene, increasing the mutational rate to 64% in our cohort. All these cases displayed a severe phenotype of cobblestone lissencephaly A. TMEM5 mutations were frequently associated with gonadal dysgenesis and neural tube defects, and ISPD mutations were frequently associated with brain vascular anomalies