40 research outputs found

    Of Genes and Patients: Stochastic Dynamic Causal Modelling of the Prefrontal-Hippocampal Network

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    The research field of functional magnetic resonance imaging (fMRI) has made possible a remarkable progress in the understanding of the human brain enabling neuroscientists to study spatio-temporal alterations in the healthy and the diseased brain. While current theories of schizophrenia stress the critical role that plays aberrant connectivity among brain regions, other theories point towards the crucial role that plays functional excitation-inhibition (E-I) balance. Indeed, recent neuroscientific research has revealed increasing evidence that taking functional brain connectivity into account is essential to understand how the human brain works, and many studies have reviewed that serious behavioural impairments in mental disorders such as schizophrenia result from increases in the functional (E-I) balance within the neural microcircuitry. Particularly, the connection between the dorsolateral prefrontal cortex (DLPFC) and the hippocampal formation (HF) during working memory (WM) was found to be increased in carriers of schizophrenia risk genes and patients. However, less is known about causality, i.e. which region drives the altered connection. Stochastic Dynamic Causal Modelling (sDCM) is a novel mathematical algorithm for studying the causal connectivity among higher cognitive brain regions from fMRI data. The main purpose of this study is to identify alterations on genetic risk carriers and patients from the DLPFC-HF network estimated with sDCM and describe how these alterations have an impact on the behavior. Over the study, we strive to give to the sDCM parameter estimates a neurobiological explanation by linking the concepts of causal connectivity with functional (E-I) balance. In this work, we applied this methodology in two samples by constructing a systematic set of sDCMs describing interactions between right DLPFC and left HF. In a first sample, 180 healthy subjects were measured by fMRI during a standard working memory N-Back task at three different sites (Mannheim, Bonn, Berlin; each with 60 participants). Bayes Model Selection (BMS) revealed the same causal pattern or winning model across the three sites, with the 2-Back working memory condition as driving input to both DLPFC and HF and with a connection from DLPFC to HF. Furthermore, a genome-wide risk variant for schizophrenia: ZNF804A (rs1344706), showed a strong impact on the DLPFC-HF network. On the one hand, risk homozygotes showed higher effective connectivity or higher functional (E-I) balance between DLPFC and HF. On the other hand, risk allele carriers showed higher functional (E-I) balance on the self-connection in the DLPFC. In a second sample, 33 schizophrenia patients were measured by fMRI during the same working memory N-Back task. We pair-wise matched healthy volunteers of the first sample and patients and applied the same methodology. BMS revealed the same winning model in patients but sDCM parameter estimates differed significantly between groups. Patients showed higher functional (E-I) balance on both self-connections in comparison to healthy volunteers. In summary, we observed that risk allele carriers and patients have a higher functional (E-I) balance within the DLPFC-HF network. In view of these research findings, we hypothesized a possible biological functioning of ZNF804A (rs1344706) on the DLPFC-HF network and suggested a mechanistic model for explaining the underlying neurobiology of schizophrenia within this network. Then, we reported causal relations between sDCM parameter estimates and behavior in terms of functional (E-I) balance in both samples. On the one hand, we observed that risk allele carriers and patients require lower functional (E-I) balance on the DLPFC-HF network in order to achieve the best performance during the task. On the other hand, we found that healthy volunteers require higher functional (E-I) balance on the network in order to achieve the optimal behavior. This study investigated the applicability of computational models like sDCM to establish the functional significance of specific genetic polymorphisms for schizophrenia and identify causal mechanisms associated with the disease in relation to the underlying neurobiology and behavior. In forthcoming studies, we plan to investigate whether subject-specific directed connections strengths between DLPFC and HF, and genotype, contain sufficiently rich information to enable accurate predictions of behavior. In order to study how temporal patterns in the neuronal ensembles and genotype convey robust information about behavior, multivariate regressors or statistical decoding algorithms will be used in both samples

    Digital Beamforming Implementation on an FPGA Platform

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    This work is part of UPC contribution to the CORPA (Cost-Optimised high Performance Active Receive Phase Array antenna for mobile terminals) project of ESA (European Space Agency)The objective of the work presented is to implement a Digital Beamforming (DBF) platform for an antenna array receiver designed for the S-DMB system. Our project deals with the design of antenna arrays from a hardware point of view, in contrast to other theo- retic studies regarding DBF algorithms. Hence, we will study practical aspects of DBF implementation such as signal quantization and required computational resources

    Mindfulness y rehabilitación neurocognitiva

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    Resumen: Los últimos datos aportados por la Comisión Europea señalan que la demencia afecta actualmente a casi cincuenta millones de personas en todo el mundo y que cada año se detectan 7.7 millones de nuevos casos. A día de hoy, el Alzheimer es la demencia más padecida por la población mundial pudiendo constituir en términos relativos el 70% de las demencias. En la actualidad no existen tratamientos farmacológicos que den una respuesta definitiva a este tipo de patologías. Las utilizaciones de terapias no farmacológicas abren un amplio abanico de posibilidades desde el ámbito de la prevención, y de la mejora de la calidad de vida en cuidadores y familiares de enfermos con demencia, básicamente con sintomatología de “sobrecarga”. En este articulo hacemos una revisión sobre investigaciones relacionadas con la “atención plena” ( MF) y de su implementación como estrategias potenciales en el abordaje de este tipo de patologías. Los últimos trabajos aportados con técnicas morfométricas por neuroimagen constituyen un importante avance a la hora de intentar aportar evidencia científica en este campo.Abstract: Nowadays approximately fifty million persons are suffering from dementia throughout the world according to the latest statistics of the European Commission (2016). Moreover, every year new 7.7 million instances of this disease are detected. At this moment, Alzheimer’s disease would be the most common mental disorder in terms of world population health, in other words, this disease can signify 70% of all dementia. Even now pharmacological treatments are ineffective. Consequently, utilization of non pharmacological therapies is opening a wide range of possibilities aimed to increase prevention and, at the same time, improvement in living standards of careers and relatives of patients with dementia who are usually overburdened. This presentation contains a review about researches on mindfulness (MF) and its implementation like potentially strategies aimed to treat this disorder

    M2 Cortex-Dorsolateral striatum stimulation reverses motor symptoms and synaptic deficits in Huntington's Disease

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    Huntington's disease (HD) is a neurological disorder characterized by motor disturbances. HD pathology is most prominent in the striatum, the central hub of the basal ganglia. The cerebral cortex is the main striatal afferent, and progressive cortico-striatal disconnection characterizes HD. We mapped striatal network dysfunction in HD mice to ultimately modulate the activity of a specific cortico-striatal circuit to ameliorate motor symptoms and recover synaptic plasticity. Multimodal MRI in vivo indicates cortico-striatal and thalamo-striatal functional network deficits and reduced glutamate/glutamine ratio in the striatum of HD mice. Moreover, optogenetically-induced glutamate release from M2 cortex terminals in the dorsolateral striatum (DLS) was undetectable in HD mice and striatal neurons show blunted electrophysiological responses. Remarkably, repeated M2-DLS optogenetic stimulation normalized motor behavior in HD mice and evoked a sustained increase of synaptic plasticity. Overall, these results reveal that selective stimulation of the M2-DLS pathway can become an effective therapeutic strategy in HD

    Yukawa Unification and the Superpartner Mass Scale

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    Naturalness in supersymmetry (SUSY) is under siege by increasingly stringent LHC constraints, but natural electroweak symmetry breaking still remains the most powerful motivation for superpartner masses within experimental reach. If naturalness is the wrong criterion then what determines the mass scale of the superpartners? We motivate supersymmetry by (1) gauge coupling unification, (2) dark matter, and (3) precision b-tau Yukawa unification. We show that for an LSP that is a bino-Higgsino admixture, these three requirements lead to an upper-bound on the stop and sbottom masses in the several TeV regime because the threshold correction to the bottom mass at the superpartner scale is required to have a particular size. For tan beta about 50, which is needed for t-b-tau unification, the stops must be lighter than 2.8 TeV when A_t has the opposite sign of the gluino mass, as is favored by renormalization group scaling. For lower values of tan beta, the top and bottom squarks must be even lighter. Yukawa unification plus dark matter implies that superpartners are likely in reach of the LHC, after the upgrade to 14 (or 13) TeV, independent of any considerations of naturalness. We present a model-independent, bottom-up analysis of the SUSY parameter space that is simultaneously consistent with Yukawa unification and the hint for m_h = 125 GeV. We study the flavor and dark matter phenomenology that accompanies this Yukawa unification. A large portion of the parameter space predicts that the branching fraction for B_s to mu^+ mu^- will be observed to be significantly lower than the SM value.Comment: 34 pages plus appendices, 20 figure

    Physics searches at the LHC

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    With the LHC up and running, the focus of experimental and theoretical high energy physics will soon turn to an interpretation of LHC data in terms of the physics of electroweak symmetry breaking and the TeV scale. We present here a broad review of models for new TeV-scale physics and their LHC signatures. In addition, we discuss possible new physics signatures and describe how they can be linked to specific models of physics beyond the Standard Model. Finally, we illustrate how the LHC era could culminate in a detailed understanding of the underlying principles of TeV-scale physics.Comment: 184 pages, 55 figures, 14 tables, hundreds of references; scientific feedback is welcome and encouraged. v2: text, references and Overview Table added; feedback still welcom

    Spatiotemporal Characteristics of the Largest HIV-1 CRF02_AG Outbreak in Spain: Evidence for Onward Transmissions

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    Background and Aim: The circulating recombinant form 02_AG (CRF02_AG) is the predominant clade among the human immunodeficiency virus type-1 (HIV-1) non-Bs with a prevalence of 5.97% (95% Confidence Interval-CI: 5.41–6.57%) across Spain. Our aim was to estimate the levels of regional clustering for CRF02_AG and the spatiotemporal characteristics of the largest CRF02_AG subepidemic in Spain.Methods: We studied 396 CRF02_AG sequences obtained from HIV-1 diagnosed patients during 2000–2014 from 10 autonomous communities of Spain. Phylogenetic analysis was performed on the 391 CRF02_AG sequences along with all globally sampled CRF02_AG sequences (N = 3,302) as references. Phylodynamic and phylogeographic analysis was performed to the largest CRF02_AG monophyletic cluster by a Bayesian method in BEAST v1.8.0 and by reconstructing ancestral states using the criterion of parsimony in Mesquite v3.4, respectively.Results: The HIV-1 CRF02_AG prevalence differed across Spanish autonomous communities we sampled from (p < 0.001). Phylogenetic analysis revealed that 52.7% of the CRF02_AG sequences formed 56 monophyletic clusters, with a range of 2–79 sequences. The CRF02_AG regional dispersal differed across Spain (p = 0.003), as suggested by monophyletic clustering. For the largest monophyletic cluster (subepidemic) (N = 79), 49.4% of the clustered sequences originated from Madrid, while most sequences (51.9%) had been obtained from men having sex with men (MSM). Molecular clock analysis suggested that the origin (tMRCA) of the CRF02_AG subepidemic was in 2002 (median estimate; 95% Highest Posterior Density-HPD interval: 1999–2004). Additionally, we found significant clustering within the CRF02_AG subepidemic according to the ethnic origin.Conclusion: CRF02_AG has been introduced as a result of multiple introductions in Spain, following regional dispersal in several cases. We showed that CRF02_AG transmissions were mostly due to regional dispersal in Spain. The hot-spot for the largest CRF02_AG regional subepidemic in Spain was in Madrid associated with MSM transmission risk group. The existence of subepidemics suggest that several spillovers occurred from Madrid to other areas. CRF02_AG sequences from Hispanics were clustered in a separate subclade suggesting no linkage between the local and Hispanic subepidemics

    EDUCACIÓN AMBIENTAL Y SOCIEDAD. SABERES LOCALES PARA EL DESARROLLO Y LA SUSTENTABILIDAD

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    Este texto contribuye al análisis científico de varias áreas del conocimiento como la filosofía social, la patología, la educación para el cuidado del medio ambiente y la sustentabilidad que inciden en diversas unidades de aprendizaje de la Licenciatura en Educación para la Salud y de la Maestría en Sociología de la SaludLas comunidades indígenas de la sierra norte de Oaxaca México, habitan un territorio extenso de biodiversidad. Sin que sea una área protegida y sustentable, la propia naturaleza de la región ofrece a sus visitantes la riqueza de la vegetación caracterizada por sus especies endémicas que componen un paisaje de suma belleza

    Digital Beamforming Implementation on an FPGA Platform

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    This work is part of UPC contribution to the CORPA (Cost-Optimised high Performance Active Receive Phase Array antenna for mobile terminals) project of ESA (European Space Agency)The objective of the work presented is to implement a Digital Beamforming (DBF) platform for an antenna array receiver designed for the S-DMB system. Our project deals with the design of antenna arrays from a hardware point of view, in contrast to other theo- retic studies regarding DBF algorithms. Hence, we will study practical aspects of DBF implementation such as signal quantization and required computational resources

    Digital Beamforming Implementation on an FPGA Platform

    No full text
    This work is part of UPC contribution to the CORPA (Cost-Optimised high Performance Active Receive Phase Array antenna for mobile terminals) project of ESA (European Space Agency)The objective of the work presented is to implement a Digital Beamforming (DBF) platform for an antenna array receiver designed for the S-DMB system. Our project deals with the design of antenna arrays from a hardware point of view, in contrast to other theo- retic studies regarding DBF algorithms. Hence, we will study practical aspects of DBF implementation such as signal quantization and required computational resources
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