Anticipated Synchronization in a Biologically Plausible Model of Neuronal Motifs

Two identical autonomous dynamical systems coupled in a master-slave configuration can exhibit anticipated synchronization (AS) if the slave also receives a delayed negative self-feedback. Recently, AS was shown to occur in systems of simplified neuron models, requiring the coupling of the neuronal membrane potential with its delayed value. However, this coupling has no obvious biological correlate. Here we propose a canonical neuronal microcircuit with standard chemical synapses, where the delayed inhibition is provided by an interneuron. In this biologically plausible scenario, a smooth transition from delayed synchronization (DS) to AS typically occurs when the inhibitory synaptic conductance is increased. The phenomenon is shown to be robust when model parameters are varied within physiological range. Since the DS-AS transition amounts to an inversion in the timing of the pre- and post-synaptic spikes, our results could have a bearing on spike-timing-dependent-plasticity models

Inhibitory autapse mediates anticipated synchronization between coupled neurons

Two identical autonomous dynamical systems unidirectionally coupled in a sender-receiver configuration can exhibit anticipated synchronization (AS) if the Receiver neuron (R) also receives a delayed negative self-feedback. Recently, AS was shown to occur in a three-neuron motif with standard chemical synapses where the delayed inhibition was provided by an interneuron. Here we show that a two-neuron model in the presence of an inhibitory autapse, which is a massive self-innervation present in the cortical architecture, may present AS. The GABAergic autapse regulates the internal dynamics of the Receiver neuron and acts as the negative delayed self-feedback required by dynamical systems in order to exhibit AS. In this biologically plausible scenario, a smooth transition from the usual delayed synchronization (DS) to AS typically occurs when the inhibitory conductance is increased. The phenomenon is shown to be robust when model parameters are varied within a physiological range. For extremely large values of the inhibitory autapse the system undergoes to a phase-drift regime in which the Receiver is faster than the Sender. Furthermore, we show that the inhibitory autapse promotes a faster internal dynamics of the free-running Receiver when the two neurons are uncoupled, which could be the mechanism underlying anticipated synchronization and the DS-AS transition.Fil: Pinto, Marcel A.. Universidade Federal de Alagoas; BrasilFil: Rosso, Osvaldo Aníbal. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Hospital Italiano. Departamento de Informática En Salud.; Argentina. Universidade Federal de Alagoas; Brasil. Universidad de Los Andes. Facultad de Medicina.; ChileFil: Matias, Fernanda S.. Universidade Federal de Alagoas; Brasi

Inhibitory loop robustly induces anticipated synchronization in neuronal microcircuits

We investigate the synchronization properties between two excitatory coupled neurons in the presence of an inhibitory loop mediated by an interneuron. Dynamic inhibition together with noise independently applied to each neuron provide phase diversity in the dynamics of the neuronal motif. We show that the interplay between the coupling strengths and the external noise controls the phase relations between the neurons in a counterintuitive way. For a master-slave configuration (unidirectional coupling) we find that the slave can anticipate the master, on average, if the slave is subject to the inhibitory feedback. In this nonusual regime, called anticipated synchronization (AS), the phase of the postsynaptic neuron is advanced with respect to that of the presynaptic neuron. We also show that the AS regime survives even in the presence of unbalanced bidirectional excitatory coupling. Moreover, for the symmetric mutually coupled situation, the neuron that is subject to the inhibitory loop leads in phase.We gratefully acknowledge CNPq Grants No. 480053/2013-8 and No. 310712/2014-9, FACEPE Grant No. APQ-0826-1.05/15, and CAPES Grant No. PVE 88881.068077/2014-01 for financial support. This article was produced as part of the activities of FAPESP Research, Innovation and Dissemination Center for Neuromathematics (Grant No. 2013/07699-0, S.Paulo Research Foundation) and it was partially funded by the Ministerio de Economía y Competitividad, España, through Project No. TEC2016-80063.Peer reviewe

A symbolic information approach to determine anticipated and delayed synchronization in neuronal circuit models

The phenomenon of synchronization between two or more areas of the brain coupled asymmetrically is a relevant issue for understanding mechanisms and functions within the cerebral cortex. Anticipated synchronization (AS) refers to the situation in which the receiver system synchronizes to the future dynamics of the sender system while the intuitively expected delayed synchronization (DS) represents exactly the opposite case. AS and DS are investigated in the context of causal information formalism. More specifically, we use a multi-scale symbolic information-theory approach for discriminating the time delay displayed between two areas of the brain when they exchange information.Instituto de Física de Líquidos y Sistemas Biológico

Exchanging screen for non-screen sitting time or physical activity might attenuate depression and anxiety: A cross-sectional isotemporal analysis during early pandemics in South America

Objectives: To examine the theoretical substitutions of screen exposure, non-screen sitting time, moderate and vigorous physical activity with depressive and anxiety symptoms in South American adults during the COVID-19 pandemic. Design: A cross-sectional study during the first months of the COVID-19 pandemic with data from 1981 adults from Chile, Argentina, and Brazil. Methods: Depressive and anxiety symptoms were assessed using the Beck Depression and Anxiety Inventories. Participants also reported physical activity, sitting time, screen exposure, sociodemographic, and tobacco use data. Isotemporal substitution models were created using multivariable linear regression methods. Results: Vigorous physical activity, moderate physical activity, and screen exposure were independently associated with depression and anxiety symptoms. In adjusted isotemporal substitution models, replacing 10 min/day of either screen exposure or non-screen sitting time with any intensity of physical activity was associated with lower levels of depressive symptoms. Improvements in anxiety symptoms were found when reallocating either screen exposure or non-screen sitting time to moderate physical activity. Furthermore, replacing 10 min/day of screen exposure with non-screen sitting time was beneficially associated with anxiety (B = − 0.033; 95 % CI = − 0.059, − 0.006) and depression (B = − 0.026; 95 % CI = − 0.050, − 0.002). Conclusions: Replacement of screen exposure with any intensity of physical activity or non-screen sitting time could improve mental health symptoms. Strategies aiming to reduce depressive and anxiety symptoms highlight physical activity promotion. However, future interventions should explore specific sedentary behaviors as some will relate positively while others negatively.Fil: Sadarangani, Kabir P.. Universidad Autónoma de Chile; Chile. Universidad Diego Portales; ChileFil: Schuch, Felipe Barreto. Universidade Federal de Santa Maria; Brasil. Universidad Autónoma de Chile; ChileFil: de Roia, Gabriela Fernanda. Universidad de Flores. Laboratorio de Estudios en Actividad Física;Fil: Martínez Gomez, David. Universidad Autónoma de Madrid; España. Consejo Superior de Investigaciones Científicas; España. Consortium for Biomedical Research in Epidemiology and Public Health; EspañaFil: Chávez, Róbinson. Universidad Andrés Bello; ChileFil: Lobo, Pablo Roberto. Universidad de Flores. Laboratorio de Estudios en Actividad Física;Fil: Cristi Montero, Carlos. Pontificia Universidad Católica de Valparaíso; ChileFil: Werneck, André O.. Universidade de Sao Paulo; BrasilFil: Alzahrani, Hosam. Taif University; Arabia SauditaFil: Ferrari, Gerson. Universidad de Santiago de Chile; ChileFil: Ibañez, Agustin Mariano. Universidad de San Andrés; Argentina. University of California; Estados Unidos. Trinity College Dublin; Irlanda. Universidad Adolfo Ibañez; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Silva, Danilo R.. Universidade Federal de Sergipe; Brasil. Universidad Pablo de Olavide; EspañaFil: Von Oetinger, Astrid. Universidad Diego Portales; Chile. Universidad Mayor; ChileFil: Matias, Thiago S.. Universidade Federal de Santa Catarina; BrasilFil: Grabovac, Igor. Universidad de Viena; AustriaFil: Meyer, Jacob. Iowa State University; Estados Unido

Enterovirus detection in stool samples from Mozambican children with acute gastroenteritis

Funding Information: Diocreciano Bero, Ph.D. was supported by Brazilian National Council for Scientific and Technological Development and the Academy of Sciences for the Developing World (CNPq/TWAS, grant number 190,897/2015–5). The ViNaDia was sponsored by Gavi, the Vaccine Alliance through Centers for Disease Control and Prevention (CDC) , Atlanta and World Health Organization, Regional Office for Africa (WHO/AFRO), Deutsche Forschungsgemeinschaft (DFG, grant number JO369/5–1). Nilsa de Deus was fellowship of the European Foundation Initiative into African Research in Neglected Tropical Diseases (EFINTD, grant number 89,539). Publisher Copyright: © 2022Enteroviruses (EV) are predominantly enteric viruses, present in all parts of the world causing disease in humans with a broad spectrum of clinical presentations. The purpose of this study was to identify non-polio enteroviruses (NPEV) in stool samples collected from children with acute gastroenteritis (AGE) symptoms of unknown etiology in four provinces (Maputo, Nampula, Sofala and Zambézia) of Mozambique. From June 2014 to March 2018, 327 stool samples were collected from children hospitalized with AGE in health care units. NPEVs were detected in 52 samples (52/327; 15.9%) and were more frequent in children under 5 years of age. The age group from 12 to 23 months was the most affected and showed more severity of disease. We also identified 26 different EV-types with the following detection pattern EV-B>EV-C>EV-A. The major EV-types were EV-A119 (9/52; 17.3%) and EV-C99 (8/52; 15.4%), accounting for 32.7% of the total. In addition to EV-A119, other uncommon EV-types were also identified, such as EV-B75, EV-B97 and EV-C113. The current study shows a high heterogeneity of EV types circulating in children with AGE in Mozambique as well as the identification of rarely described enteroviruses.publishersversionpublishe