485 research outputs found

    Cognitive Control of Escape Behaviour

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    When faced with potential predators, animals instinctively decide whether there is a threat they should escape from, and also when, how, and where to take evasive action. While escape is often viewed in classical ethology as an action that is released upon presentation of specific stimuli, successful and adaptive escape behaviour relies on integrating information from sensory systems, stored knowledge, and internal states. From a neuroscience perspective, escape is an incredibly rich model that provides opportunities for investigating processes such as perceptual and value-based decision-making, or action selection, in an ethological setting. We review recent research from laboratory and field studies that explore, at the behavioural and mechanistic levels, how elements from multiple information streams are integrated to generate flexible escape behaviour

    Flexible inhibitory control of visually evoked defensive behavior by the ventral lateral geniculate nucleus

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    Animals can choose to act upon, or to ignore, sensory stimuli, depending on circumstance and prior knowledge. This flexibility is thought to depend on neural inhibition, through suppression of inappropriate and disinhibition of appropriate actions. Here, we identified the ventral lateral geniculate nucleus (vLGN), an inhibitory prethalamic area, as a critical node for control of visually evoked defensive responses in mice. The activity of vLGN projections to the medial superior colliculus (mSC) is modulated by previous experience of threatening stimuli, tracks the perceived threat level in the environment, and is low prior to escape from a visual threat. Optogenetic stimulation of the vLGN abolishes escape responses, and suppressing its activity lowers the threshold for escape and increases risk-avoidance behavior. The vLGN most strongly affects visual threat responses, potentially via modality-specific inhibition of mSC circuits. Thus, inhibitory vLGN circuits control defensive behavior, depending on an animal’s prior experience and its anticipation of danger in the environment

    Flexible inhibitory control of visually evoked defensive behavior by the ventral lateral geniculate nucleus

    Get PDF
    Animals can choose to act upon, or to ignore, sensory stimuli, depending on circumstance and prior knowledge. This flexibility is thought to depend on neural inhibition, through suppression of inappropriate and disinhibition of appropriate actions. Here, we identified the ventral lateral geniculate nucleus (vLGN), an inhibitory prethalamic area, as a critical node for control of visually evoked defensive responses in mice. The activity of vLGN projections to the medial superior colliculus (mSC) is modulated by previous experience of threatening stimuli, tracks the perceived threat level in the environment, and is low prior to escape from a visual threat. Optogenetic stimulation of the vLGN abolishes escape responses, and suppressing its activity lowers the threshold for escape and increases risk-avoidance behavior. The vLGN most strongly affects visual threat responses, potentially via modality-specific inhibition of mSC circuits. Thus, inhibitory vLGN circuits control defensive behavior, depending on an animal’s prior experience and its anticipation of danger in the environment

    STORMTOOLS: Coastal Environmental Risk Index (CERI)

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    One of the challenges facing coastal zone managers and municipal planners is the development of an objective, quantitative assessment of the risk to structures, infrastructure, and public safety that coastal communities face from storm surge in the presence of changing climatic conditions, particularly sea level rise and coastal erosion. Here we use state of the art modeling tool (ADCIRC and STWAVE) to predict storm surge and wave, combined with shoreline change maps (erosion), and damage functions to construct a Coastal Environmental Risk Index (CERI). Access to the state emergency data base (E-911) provides information on structure characteristics and the ability to perform analyses for individual structures. CERI has been designed as an on line Geographic Information System (GIS) based tool, and hence is fully compatible with current flooding maps, including those from FEMA. The basic framework and associated GIS methods can be readily applied to any coastal area. The approach can be used by local and state planners to objectively evaluate different policy options for effectiveness and cost/benefit. In this study, CERI is applied to RI two communities; Charlestown representing a typical coastal barrier system directly exposed to ocean waves and high erosion rates, with predominantly low density single family residences and Warwick located within Narragansett Bay, with more limited wave exposure, lower erosion rates, and higher residential housing density. Results of these applications are highlighted herein

    Defective synapse maturation and enhanced synaptic plasticity in Shank2 Δex7(-/-) mice

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    Autism spectrum disorders (ASDs) are neurodevelopmental disorders with a strong genetic etiology. Since mutations in human SHANK genes have been found in patients with autism, genetic mouse models are used for a mechanistic understanding of ASDs and the development of therapeutic strategies. SHANKs are scaffold proteins in the postsynaptic density of mammalian excitatory synapses with proposed functions in synaptogenesis, regulation of dendritic spine morphology, and instruction of structural synaptic plasticity. In contrast to all studies so far on the function of SHANK proteins, we have previously observed enhanced synaptic plasticity in Shank2 Δex7(-/-) mice. In a series of experiments, we now reproduce these results, further explore the synaptic phenotype, and directly compare our model to the independently generated Shank2 Δex6-7(-/-) mice. Minimal stimulation experiments reveal that Shank2 Δex7(-/-) mice possess an excessive fraction of silent (i.e., α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, short, AMPA receptor lacking) synapses. The synaptic maturation deficit emerges during the third postnatal week and constitutes a plausible mechanistic explanation for the mutants' increased capacity for long-term potentiation, both in vivo and in vitro. A direct comparison with Shank2 Δex6-7(-/-) mice adds weight to the hypothesis that both mouse models show a different set of synaptic phenotypes, possibly due to differences in their genetic background. These findings add to the diversity of synaptic phenotypes in neurodevelopmental disorders and further support the supposed existence of "modifier genes" in the expression and inheritance of ASDs

    Effect of inhaled corticosteroid particle size on asthma efficacy and safety outcomes: a systematic literature review and meta-analysis

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    BACKGROUND: Inhaled corticosteroids (ICS) are the primary treatment for persistent asthma. Currently available ICS have differing particle size due to both formulation and propellant, and it has been postulated that this may impact patient outcomes. This structured literature review and meta-analysis compared the effect of small and standard particle size ICS on lung function, symptoms, rescue use (when available) and safety in patients with asthma as assessed in head-to-head randomized controlled trials (RCTs). METHODS: A systematic literature search of MEDLINE was performed to identify RCTs (1998-2014) evaluating standard size (fluticasone propionate-containing medications) versus small particle size ICS medication in adults and children with asthma. Efficacy outcomes included forced expiratory volume in 1 s (FEV1), morning peak expiratory flow (PEF), symptom scores, % predicted forced expiratory flow between 25 and 75% of forced vital capacity (FEF25-75%), and rescue medication use. Safety outcomes were also evaluated when available. RESULTS: Twenty-three independent trials that met the eligibility criteria were identified. Benefit-risk plots did not demonstrate any clinically meaningful differences across the five efficacy endpoints considered and no appreciable differences were noted for most safety endpoints. Meta-analysis results, using a random-effects model, demonstrated no significant difference between standard and small size particle ICS medications in terms of effects on mean change from baseline FEV1 (L) (-0.011, 95% confidence interval [CI]: -0.037, 0.014 [N = 3524]), morning PEF (L/min) (medium/low doses: -3.874, 95% CI: -10.915, 3.166 [N = 1911]; high/high-medium doses: 5.551, 95% CI: -1.948, 13.049 [N = 749]) and FEF25-75% predicted (-2.418, 95% CI: -6.400; 1.564 [N = 115]). CONCLUSIONS: Based on the available literature, no clinically significant differences in efficacy or safety were observed comparing small and standard particle size ICS medications for the treatment of asthma. TRIAL REGISTRATION: GSK Clinical Study Register No: 202012

    Clinicopathological correlations of mesenteric fibrosis and evaluation of a novel biomarker for fibrosis detection in small bowel neuroendocrine neoplasms

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    PURPOSE: Mesenteric fibrosis (MF) in small intestinal neuroendocrine neoplasms (SINENs) is often associated with significant morbidity and mortality. The detection of MF is usually based on radiological criteria, but no previous studies have attempted a prospective, multidimensional assessment of mesenteric desmoplasia to determine the accuracy of radiological measurements. There is also a lack of non-invasive biomarkers for the detection of image-negative MF. METHODS: A multidimensional assessment of MF incorporating radiological, surgical and histological parameters was performed in a prospective cohort of 34 patients with SINENs who underwent primary resection. Pre-operative blood samples were collected in 20 cases to evaluate a set of five profibrotic circulating transcripts-the "fibrosome"-that is included as an "omic" component of the NETest. RESULTS: There was a significant correlation between radiological and surgical assessments of MF (p < 0.05). However, there were several cases of image-negative MF. The NETest-fibrosome demonstrated an accuracy of 100% for the detection of microscopic MF. CONCLUSIONS: The detection of MF by radiological criteria has limitations. The NETest-fibrosome is a promising biomarker for fibrosis detection and further validation of these results would be needed in larger, multicentre studies

    Serious asthma events with fluticasone plus salmeterol versus fluticasone alone

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    Background: the safe and appropriate use of long-acting beta-agonists (LABAs) for the treatment of asthma has been widely debated. In two large clinical trials, investigators found a potential risk of serious asthma-related events associated with LABAs. This study was designed to evaluate the risk of administering the LABA salmeterol in combination with an inhaled glucocorticoid, fluticasone propionate. Methods: in this multicenter, randomized, double-blind trial, adolescent and adult patients (age, ≥12 years) with persistent asthma were assigned to receive either fluticasone with salmeterol or fluticasone alone for 26 weeks. All the patients had a history of a severe asthma exacerbation in the year before randomization but not during the previous month. Patients were excluded from the trial if they had a history of life-threatening or unstable asthma. The primary safety end point was the first serious asthma-related event (death, endotracheal intubation, or hospitalization). Noninferiority of fluticasone-salmeterol to fluticasone alone was defined as an upper boundary of the 95% confidence interval for the risk of the primary safety end point of less than 2.0. The efficacy end point was the first severe asthma exacerbation. Results: of 11,679 patients who were enrolled, 67 had 74 serious asthma-related events, with 36 events in 34 patients in the fluticasone-salmeterol group and 38 events in 33 patients in the fluticasone-only group. The hazard ratio for a serious asthma-related event in the fluticasone-salmeterol group was 1.03 (95% confidence interval [CI], 0.64 to 1.66), and noninferiority was achieved (P=0.003). There were no asthma-related deaths; 2 patients in the fluticasone-only group underwent asthma-related intubation. The risk of a severe asthma exacerbation was 21% lower in the fluticasone-salmeterol group than in the fluticasone-only group (hazard ratio, 0.79; 95% CI, 0.70 to 0.89), with at least one severe asthma exacerbation occurring in 480 of 5834 patients (8%) in the fluticasone-salmeterol group, as compared with 597 of 5845 patients (10%) in the fluticasone-only group (P<0.001). Conclusions: patients who received salmeterol in a fixed-dose combination with fluticasone did not have a significantly higher risk of serious asthma-related events than did those who received fluticasone alone. Patients receiving fluticasone-salmeterol had fewer severe asthma exacerbations than did those in the fluticasone-only group. (AUSTRI ClinicalTrials.gov number, NCT01475721)
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