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Gema Martinez-Navarrete,1,2 Sergio Castaño-Castaño,3– 6 Miguel Morales-Navas,4 Francisco Nieto-Escámez,4,7 Fernando Sánchez-Santed,4 Eduardo Fernandez1,2 1Neuroprosthesis and Neuroengineering Research Group, Institute of Bioengineering (IB), University Miguel Hernández (UMH), Elche, 03020, Spain; 2Networking Research Centre of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Zaragoza, Spain; 3Department Psychology, University of Oviedo, Plaza Feijoo S/N, Oviedo, 33003, Spain; 4Department of Psychology, University of Almería, Ctra. Sacramento S/N, La Cañada de San Urbano, Almería, 04120, Spain; 5Institute of Neurosciences of the Principality of Asturias (INEUROPA), Oviedo, Spain; 6Institute of Health Research of the Principality of Asturias (ISPA), Oviedo, Spain; 7Neuropsychological Evaluation and Rehabilitation Center (CERNEP), Ctra. Sacramento S/N, La Cañada de San Urbano, Almería, 04120, SpainCorrespondence: Gema Martinez-Navarrete, Department of Histology and Anatomy (Faculty of Medicine). Neuroengineering Biomedical Research Group, Institute of Bioengineering, University Miguel Hernandez, Elche, 03202, Spain, Email gema.martinezn@umh.es Sergio Castaño-Castaño, Department Psychology, University of Oviedo, Plaza Feijoo s/n, Asturias, 33003, Spain, Email castanosergio@uniovi.esPurpose: The impact of visual deprivation on retinal structure is widely debated. Experimental models, like monocular deprivation through lid suture, provide insights into the consequences of lacking visual experience during development. This deprivation delays primary visual cortex (CV1) maturation due to improper neural connection consolidation, which remains plastic beyond the critical period. However, few studies have used Optical Coherence Tomography (OCT) to investigate structural alterations in the retina of animal models following monocular deprivation. Instead, some studies have focused on the ganglion cell layer using post-mortem histological techniques in amblyopia models induced by monocular deprivation.Methods: In this study, we used Cliff test to assess stereoscopic vision and spectral domain optical coherence tomography (SD-OCT) to evaluate retinal changes in an in vivo model of visual deprivation treated with Transcranial Direct Current Stimulation (tDCS).Results: The depth perception test initially revealed differences between individuals with amblyopia and the control group. However, after 8 tDCS sessions, amblyopic subjects matched the control group’s performance, which remained stable Additionally, significant changes were observed in retinal structures post-tDCS treatment. Specifically, the thickness of the Nerve Fiber Layer + Ganglion Cell Layer + Inner Plexiform Layer (NFL+GCL+IPL) increased significantly in amblyopic eyes (p< 0.001). Moreover, significant retinal thickening, including the Nerve Fiber Layer + Ganglion Cell Layer + Inner Plexiform Layer (NFL+GCL+IPL) and the entire retina, was observed post-tDCS treatment (p< 0.05), highlighting the critical role of tDCS in ameliorating amblyopia. Additionally, treated animals exhibited reduced thickness in the Inner Nuclear Layer (INL) and Outer Nuclear Layer (ONL).Conclusion: tDCS treatment effectively restores amblyopic individuals’ stereoscopic vision, aligning their performance with controls, while impacting retinal structure, highlighting its potential in ameliorating amblyopia’s visual deficits. Keywords: amblyopia, monocular visual deprivation model, tDCS, stereoscopic vision, OCT

Fmr1 (fragile X messenger ribonucleoprotein 1)-knockout (KO) rats, modeling the human Fragile X Syndrome (FXS), are of particular interest for exploring the ASD-like phenotype in preclinical studies. Gestational exposure to chlorpyrifos (CPF) has been associated with ASD diagnosis in humans and ASD-like behaviors in rodents and linked to the microbiota-gut-brain axis. In this study, we have used both Fmr1-KO and wild-type male rats (F2 generation) at postnatal days (PND) 7 and 40 obtained after F1 pregnant females were randomly exposed to 1 mg/kg/mL/day of CPF or vehicle. A nuclear magnetic resonance (NMR) metabolomics approach together with gene expression profiles of these F2 generation rats were employed to analyze different brain regions (such as prefrontal cortex, hippocampus, and cerebellum), whole large intestine (at PND7) and gut content (PND40). The statistical comparison of each matrix spectral profile unveiled tissue-specific metabolic fingerprints. Significant variations in some biomarker levels were detected among brain tissues of different genotypes, including taurine, myo-inositol, and 3-hydroxybutyric acid, and exposure to CPF induced distinct metabolic alterations, particularly in serine and myo-inositol. Additionally, this study provides a set of metabolites associated with gastrointestinal dysfunction in ASD, encompassing several amino acids, choline-derived compounds, bile acids, and sterol molecules. In terms of gene expression, genotype and gestational exposure to CPF had only minimal effects on decarboxylase 2 (gad2) and cholinergic receptor muscarinic 2 (chrm2) genes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

In recent years, exposures to organophosphate pesticide have been highlighted as a possible cause or aggravating factor of autism spectrum disorder (ASD). The present study examined if Wistar rats prenatally exposed to chlorpyrifos (CPF) at a dose of 1 mg/kg in GD 12.5-15.5 could express similar behaviors to those exposed to valproic acid (VPA, 400 mg/kg) during the same administration window, which is an accepted animal model of autism. The 3-chambered test was employed to evaluate sociability and reaction to social novelty in two experiments, the first in adolescence and the second in adulthood. The results obtained in this study show that animals prenatally treated with CPF or VPA show a similar behavioral phenotype compared to the control group (CNT). In adolescence, the CPF animals showed a negative index in the reaction to social novelty, followed closely by the VPA, while both experimental groups showed a recovery in this aspect during adulthood. This study therefore provides evidence to suggest that prenatal exposure to CPF in rats could have similar effects on certain components of sociability to those seen in autistic models., (© 2024. The Author(s).)