Cerebellar purkinje cells can differentially modulate coherence between sensory and motor cortex depending on region and behavior

Activity of sensory and motor cortices is essential for sensorimotor integration. In particular, coherence between these areas may indicate binding of critical functions like perception, motor planning, action, or sleep. Evidence is accumulating that cerebellar output modulates cortical activity and coherence, but how, when, and where it does so is unclear. We studied activity in and coherence between S1 and M1 cortices during whisker stimulation in the absence and presence of optogenetic Purkinje cell stimulation in crus 1 and 2 of awake mice, eliciting strong simple spike rate modulation. Without Purkinje cell stimulation, whisker stimulation triggers fast responses in S1 and M1 involving transient coherence in a broad spectrum. Simultaneous stimulation of Purkinje cells and whiskers affects amplitude and kinetics of sensory responses in S1 and M1 and alters the estimated S1–M1 coherence in theta and gamma bands, allowing bidirectional control dependent on behavioral context. These effects are absent when Purkinje cell activation is delayed by 20 ms. Focal stimulation of Purkinje cells revealed site specificity, with cells in medial crus 2 showing the most prominent and selective impact on estimated coherence, i.e., a strong suppression in the gamma but not the theta band. Granger causality analyses and computational modeling of the involved networks suggest that Purkinje cells control S1–M1 phase consistency predominantly via ventrolateral thalamus and M1. Our results indicate that activity of sensorimotor cortices can be dynamically and functionally modulated by specific cerebellar inputs, highlighting a widespread role of the cerebellum in coordinating sensorimotor behavior

Sudden Cardiac Death Prediction in Arrhythmogenic Right Ventricular Cardiomyopathy: A Multinational Collaboration

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is associated with ventricular arrhythmias (VA) and sudden cardiac death (SCD). A model was recently developed to predict incident sustained VA in patients with ARVC. However, since this outcome may overestimate the risk for SCD, we aimed to specifically predict life-threatening VA (LTVA) as a closer surrogate for SCD. METHODS: We assembled a retrospective cohort of definite ARVC cases from 15 centers in North America and Europe. Association of 8 prespecified clinical predictors with LTVA (SCD, aborted SCD, sustained, or implantable cardioverter-defibrillator treated ventricular tachycardia >250 beats per minute) in follow-up was assessed by Cox regression with backward selection. Candidate variables included age, sex, prior sustained VA (≥30s, hemodynamically unstable, or implantable cardioverter-defibrillator treated ventricular tachycardia; or aborted SCD), syncope, 24-hour premature ventricular complexes count, the number of anterior and inferior leads with T-wave inversion, left and right ventricular ejection fraction. The resulting model was internally validated using bootstrapping. RESULTS: A total of 864 patients with definite ARVC (40±16 years; 53% male) were included. Over 5.75 years (interquartile range, 2.77-10.58) of follow-up, 93 (10.8%) patients experienced LTVA including 15 with SCD/aborted SCD (1.7%). Of the 8 prespecified clinical predictors, only 4 (younger age, male sex, premature ventricular complex count, and number of leads with T-wave inversion) were associated with LTVA. Notably, prior sustained VA did not predict subsequent LTVA (P=0.850). A model including only these 4 predictors had an optimism-corrected C-index of 0.74 (95% CI, 0.69-0.80) and calibration slope of 0.95 (95% CI, 0.94-0.98) indicating minimal over-optimism. CONCLUSIO

A new prediction model for ventricular arrhythmias in arrhythmogenic right ventricular cardiomyopathy

AIMS: Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVC) is characterized by ventricular arrhythmias (VAs) and sudden cardiac death (SCD). We aimed to develop a model for individualized prediction of incident VA/SCD in ARVC patients. METHODS AND RESULTS: Five hundred and twenty-eight patients with a definite diagnosis and no history of sustained VAs/SCD at baseline, aged 38.2 ± 15.5 years, 44.7% male, were enrolled from five registries in North America and Europe. Over 4.83 (interquartile range 2.44-9.33) years of follow-up, 146 (27.7%) experienced sustained VA, defined as SCD, aborted SCD, sustained ventricular tachycardia, or appropriate implantable cardioverter-defibrillator (ICD) therapy. A prediction model estimating annual VA risk was developed using Cox regression with internal validation. Eight potential predictors were pre-specified: age, sex, cardiac syncope in the prior 6 months, non-sustained ventricular tachycardia, number of premature ventricular complexes in 24 h, number of leads with T-wave inversion, and right and left ventricular ejection fractions (LVEFs). All except LVEF were retained in the final model. The model accurately distinguished patients with and without events, with an optimism-corrected C-index of 0.77 [95% confidence interval (CI) 0.73-0.81] and minimal over-optimism [calibration slope of 0.93 (95% CI 0.92-0.95)]. By decision curve analysis, the clinical benefit of the model was superior to a current consensus-based ICD placement algorithm with a 20.6% reduction of ICD placements with the same proportion of protected patients (P < 0.001). CONCLUSION: Using the largest cohort of patients with ARVC and no prior VA, a prediction model using readily available clinical parameters was devised to estimate VA risk and guide decisions regarding primary prevention ICDs (www.arvcrisk.com)

UNE MÉTHODE NUMÉRIQUE DE RÉSOLUTION DES ÉQUATIONS DE L'ACOUSTIQUE DANS UN MILIEU À CARACTÉRISTIQUES C∞ PAR MORCEAUX

Nous présentons une méthode numérique pour la résolution des systèmes d'équations de l'acoustique linéaire et faiblement non linéaire valable même lorsque le milieu comporte des dioptres avec points singuliers (arête d'un dièdre, sommet d'un cône). L'intérêt de notre méthode est qu'elle fonctionne sans aucune connaissance préalable des conditions de passage.We present a numerical method for the solution of the systems of equations of linear and weakly nonlinear acoustics valid even when the medium involves dioptra with singular points (edge of a diedra, top of a cone). The basic feature of our method is that no previous knowledge of the transmission conditions is needed

Exploring barriers to the agroecological transition in Nicaragua: A Technological Innovation Systems Approach

Latin America has historically been a vanguard of agroecology. In Nicaragua, an agroecological transition is occurring, with three decades of building a groundswell based on the farmer-to-farmer movement and the recent institutionalization of agroecology in national law. Yet, problems remain with agroecology’s diffusion. We introduce the Technological Innovation Systems approach to examine systemic barriers to the agroecological transition and cycles of blockages caused by barriers’ interactions. Based on qualitative data from north-central Nicaragua, we find the main barriers hindering the agroecological transition include weak guidance of the search for agroecology, insufficient capacities and quantities of resources, and lacking market development. Beyond the Nicaragua case, the analysis points at the importance of using socio-technical systems analysis to better understand and address the root causes behind issues blocking national agroecological transitions.</p

Nicaragua’s agroecological transition: Transformation or reconfiguration of the agri-food regime?

Agroecology started to amplify agroecology in Nicaragua in the 1980s and was translated into national policy in 2011. Using the Multi-Level Perspective on sustainability transitions (MLP), this paper explores whether the rise of agroecology has fundamentally transformed Nicaragua’s agri-food system. Drawing on the findings of a qualitative study including a range of agroecological actors and organizations, we create a rich innovation history timeline of Nicaragua’s agroecology development at different levels – the agroecological niche (space in which heterogenous actors nurture innovations) and the regime (dominant agri-food system paradigm). MLP analysis is used to explore the extent to which agroecology’s growth has transformed the national agri-food regime. We find that although the term ‘agroecology’ is used widely by government, incentives for transitions to agroecology are only weakly implemented. This stems partly from the co-optation of the agroecological niche’s discourse by regime actors. Currently, it seems the transition process is not a reconfiguration of the agri-food system, but rather that agroecology has been added to the regime without deeper changes

Le tourisme durable et la coordination des acteurs dans les territoires : quelle démarche méthodologique ?

The importance of the environmental and ethical questions conduces the businesses and the authorities to integrate them. This integration means reflection and changes in the behaviours. In the tourism domain more and more concertation and coordination processes occur. The process of change has three forms: spontaneous, negociated, or obliged change. Concerning tourism, the number of stakeholders and forms of this activity, the diversity and the diffuse nature of the impacts conduce to privilegiate concerted action. Forms of collective action in favour of sustainable tourism are identified . They have three characteristics: volontary involvement, aims in favour of environment preservation or improvement, linkage between activity and the territory. The forms of agreement are various: labels, charta Which evaluation can be made, and how, of these processes of concertation and agreement?L'importance des questions d'environnement et d'éthique dans le tourisme impose aux décideurs de les intégrer sectoriellement et territorialement. Cette intégration amène les acteurs à réfléchir, à se comporter différemment les uns envers les autres. Dans l'activité touristique, le changement de l'appréhension de l'environnement, le souci d'apporter un vernis éthique, font que l'on assiste à une multiplication des dispositifs de concertation et de coordination. Ce changement peut prendre trois formes : le changement contraint, le changement négocié, le changement spontané. En ce qui concerne le tourisme, la multiplicité des intervenants et des formes d'activité, comme la diversité et le caractère diffus des impacts et des enjeux, tendent à privilégier des dispositifs concertés. Des formes d'action collective visant un tourisme respectueux de l'environnement peuvent être identifiées. Elles présentent au moins trois caractéristiques génériques que nous souhaitons aborder : elles sont fondées sur un engagement volontaire, elles se donnent des objectifs de préservation ou d'amélioration de l'environnement, elles mettent en avant le lien entre l'activité et le territoire. Sous la notion "d'accords", on retrouve des dispositifs de nature juridique variable (labels, chartes de qualité, chartes de territoire). Quelle évaluation peut-on faire, au regard de cet enjeu, des processus de concertation et d'accord, de type " charte ", et comment la faire

Le tourisme durable et la coordination des acteurs dans les territoires : quelle démarche méthodologique ?

The importance of the environmental and ethical questions conduces the businesses and the authorities to integrate them. This integration means reflection and changes in the behaviours. In the tourism domain more and more concertation and coordination processes occur. The process of change has three forms: spontaneous, negociated, or obliged change. Concerning tourism, the number of stakeholders and forms of this activity, the diversity and the diffuse nature of the impacts conduce to privilegiate concerted action. Forms of collective action in favour of sustainable tourism are identified . They have three characteristics: volontary involvement, aims in favour of environment preservation or improvement, linkage between activity and the territory. The forms of agreement are various: labels, charta Which evaluation can be made, and how, of these processes of concertation and agreement?L'importance des questions d'environnement et d'éthique dans le tourisme impose aux décideurs de les intégrer sectoriellement et territorialement. Cette intégration amène les acteurs à réfléchir, à se comporter différemment les uns envers les autres. Dans l'activité touristique, le changement de l'appréhension de l'environnement, le souci d'apporter un vernis éthique, font que l'on assiste à une multiplication des dispositifs de concertation et de coordination. Ce changement peut prendre trois formes : le changement contraint, le changement négocié, le changement spontané. En ce qui concerne le tourisme, la multiplicité des intervenants et des formes d'activité, comme la diversité et le caractère diffus des impacts et des enjeux, tendent à privilégier des dispositifs concertés. Des formes d'action collective visant un tourisme respectueux de l'environnement peuvent être identifiées. Elles présentent au moins trois caractéristiques génériques que nous souhaitons aborder : elles sont fondées sur un engagement volontaire, elles se donnent des objectifs de préservation ou d'amélioration de l'environnement, elles mettent en avant le lien entre l'activité et le territoire. Sous la notion "d'accords", on retrouve des dispositifs de nature juridique variable (labels, chartes de qualité, chartes de territoire). Quelle évaluation peut-on faire, au regard de cet enjeu, des processus de concertation et d'accord, de type " charte ", et comment la faire

Temporal lobe dysfunction in patients with schizophrenia during performance of a speech and non-speech analogue detection task: An event-related fMRI study

Both functional and structural temporal lobe abnormalities have been linked to symptoms of auditory hallucinations and thought disorder in patients with schizophrenia. In an event-related fMRI study, we used an oddball detection task that required neither identification nor linguistic analysis, in order to determine if functional temporal lobe abnormalities are present in schizophrenia during the early stages of speech and auditory processing. 14 healthy control subjects and 14 schizophrenic patients heard Ž nonsense speech sounds and matched sine wave analogues non. speech . In a similar study completed previously in 15 healthy subjects, speech stimuli were found to elicit significantly greater activation than non-speech analogues in classic receptive language Ž. areas, namely in the middle temporal gyrus MTG and in the Ž. superior temporal gyrus STG . In the present study, this finding was replicated in the healthy control subjects. Speech stimuli were also found to elicit significantly greater activation than non-speech analogues in the MTG and in the STG of the schizophrenic patients. Nevertheless, in both the speech and non-speech conditions schizophrenic patients showed significantly less activation in the MTG and in the STG than that shown by control subjects. The detection of speech in an auditory stream is an important first step in processing spoken language. These results suggest that, although schizophrenic subjects can detect the difference between speech and non-speech at a basic level, the functioning of the receptive language areas of the temporal lobe are nonetheless impaired during the early stages of speech and auditory processin

A mode-matching model for the impedance of perforated plate liners

International audienceA mode-matching model applicable to perforated liners in the linear regime is presented.It complements semi-empirical models not suitable for the high frequency regime, for linerfeaturing thick plate and micro perforated liner. The mentioned models are compared to mea-surements. From these comparisons, it appears that removing the short tube approximationis not enough to capture completely the losses in the linear regime. Further investigations havebeen carried out using a finite element method model based on compressible Linearised Navier-Stokes equations. This method showed to be in good agreement with experimental data. Thus,the dissipation due to viscosity was mapped around the aperture. This approach is supposedto provide a more precise understanding of the physical phenomenon of interest. Based onthose results, the next step is to propose an upgraded mode-matching model computationallyefficient that overtakes empirical models thanks to physical-based modeling