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Search Results: 1 - 10 of 19727 matches for " Marie-Aurélie Bruno "
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Granger Causality Analysis of Steady-State Electroencephalographic Signals during Propofol-Induced Anaesthesia
Adam B. Barrett, Michael Murphy, Marie-Aurélie Bruno, Quentin Noirhomme, Mélanie Boly, Steven Laureys, Anil K. Seth
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0029072
Abstract: Changes in conscious level have been associated with changes in dynamical integration and segregation among distributed brain regions. Recent theoretical developments emphasize changes in directed functional (i.e., causal) connectivity as reflected in quantities such as ‘integrated information’ and ‘causal density’. Here we develop and illustrate a rigorous methodology for assessing causal connectivity from electroencephalographic (EEG) signals using Granger causality (GC). Our method addresses the challenges of non-stationarity and bias by dividing data into short segments and applying permutation analysis. We apply the method to EEG data obtained from subjects undergoing propofol-induced anaesthesia, with signals source-localized to the anterior and posterior cingulate cortices. We found significant increases in bidirectional GC in most subjects during loss-of-consciousness, especially in the beta and gamma frequency ranges. Corroborating a previous analysis we also found increases in synchrony in these ranges; importantly, the Granger causality analysis showed higher inter-subject consistency than the synchrony analysis. Finally, we validate our method using simulated data generated from a model for which GC values can be analytically derived. In summary, our findings advance the methodology of Granger causality analysis of EEG data and carry implications for integrated information and causal density theories of consciousness.
Central modulation in cluster headache patients treated with occipital nerve stimulation: an FDG-PET study
Delphine Magis, Marie-Aurélie Bruno, Arnaud Fumal, Pierre-Yves Gérardy, Roland Hustinx, Steven Laureys, Jean Schoenen
BMC Neurology , 2011, DOI: 10.1186/1471-2377-11-25
Abstract: Ten drCCH patients underwent an 18FDG-PET scan after ONS, at delays varying between 0 and 30 months. All were scanned with ongoing ONS (ON) and with the stimulator switched OFF.After 6-30 months of ONS, 3 patients were pain free and 4 had a ≥ 90% reduction of attack frequency (responders). In all patients compared to controls, several areas of the pain matrix showed hypermetabolism: ipsilateral hypothalamus, midbrain and ipsilateral lower pons. All normalized after ONS, except for the hypothalamus. Switching the stimulator ON or OFF had little influence on brain glucose metabolism. The perigenual anterior cingulate cortex (PACC) was hyperactive in ONS responders compared to non-responders.Metabolic normalization in the pain neuromatrix and lack of short-term changes induced by the stimulation might support the hypothesis that ONS acts in drCCH through slow neuromodulatory processes. Selective activation in responders of PACC, a pivotal structure in the endogenous opioid system, suggests that ONS could restore balance within dysfunctioning pain control centres. That ONS is nothing but a symptomatic treatment might be illustrated by the persistent hypothalamic hypermetabolism, which could explain why autonomic attacks may persist despite pain relief and why cluster attacks recur shortly after stimulator arrest. PET studies on larger samples are warranted to confirm these first results.Cluster headache (CH) is one of the most painful primary headaches and is characterized by attacks of severe unilateral periorbital pain associated with ipsilateral autonomic features [1]. About 10% of patients have, or develop over time, a chronic form (CCH) [2] characterised by recurrent attacks for at least 1 year without remissions or with remissions of less than 1 month [1]. About 1% of CCH patients become drug-resistant (drCCH) to most prophylactic drug treatments and fulfil published criteria for intractable headaches [3].CH is the most prevalent member of the so-called trigeminal
Visual fixation in the vegetative state: an observational case series PET study
Marie-Aurélie Bruno, Audrey Vanhaudenhuyse, Caroline Schnakers, Mélanie Boly, Olivia Gosseries, Athena Demertzi, Steve Majerus, Gustave Moonen, Roland Hustinx, Steven Laureys
BMC Neurology , 2010, DOI: 10.1186/1471-2377-10-35
Abstract: We here studied cerebral metabolism in ten patients with chronic post-anoxic encephalopathy and 39 age-matched healthy controls. Five patients were in a vegetative state (without fixation) and five presented visual fixation but otherwise showed all criteria typical of the vegetative state. Patients were matched for age, etiology and time since insult and were followed by repeated Coma Recovery Scale-Revised (CRS-R) assessments for at least 1 year. Sustained visual fixation was considered as present when the eyes refixated a moving target for more than 2 seconds as defined by CRS-R criteria.Patients without fixation showed metabolic dysfunction in a widespread fronto-parietal cortical network (with only sparing of the brainstem and cerebellum) which was not different from the brain function seen in patients with visual fixation. Cortico-cortical functional connectivity with visual cortex showed no difference between both patient groups. Recovery rates did not differ between patients without or with fixation (none of the patients showed good outcome).Our findings suggest that sustained visual fixation in (non-traumatic) disorders of consciousness does not necessarily reflect consciousness and higher order cortical brain function.It is still a matter of debate whether visual fixation indicates "automatic" subcortical processing (i.e., is compatible with the diagnosis of the vegetative state; VS [1,2]) or whether it is a cognitively mediated behavior that heralds consciousness and higher order cortical processing (i.e., sufficient for the diagnosis of the minimallyconscious state; MCS [3]). According to the Multi Society Task Force on PVS in "rare cases, patients who have no other evidence of consciousness over a period of months to years have some degree of briefly sustained visual fixation, which is believed to be mediated through brainstem structures"[1]. Similarly, UK guidelines state that "visual fixation of a target" is a "compatible but atypical feature" of the V
Dynamic Change of Global and Local Information Processing in Propofol-Induced Loss and Recovery of Consciousness
Martin M. Monti ,Evan S. Lutkenhoff,Mikail Rubinov,Pierre Boveroux,Audrey Vanhaudenhuyse,Olivia Gosseries,Marie-Aurélie Bruno,Quentin Noirhomme,Mélanie Boly,Steven Laureys
PLOS Computational Biology , 2013, DOI: 10.1371/journal.pcbi.1003271
Abstract: Whether unique to humans or not, consciousness is a central aspect of our experience of the world. The neural fingerprint of this experience, however, remains one of the least understood aspects of the human brain. In this paper we employ graph-theoretic measures and support vector machine classification to assess, in 12 healthy volunteers, the dynamic reconfiguration of functional connectivity during wakefulness, propofol-induced sedation and loss of consciousness, and the recovery of wakefulness. Our main findings, based on resting-state fMRI, are three-fold. First, we find that propofol-induced anesthesia does not bear differently on long-range versus short-range connections. Second, our multi-stage design dissociated an initial phase of thalamo-cortical and cortico-cortical hyperconnectivity, present during sedation, from a phase of cortico-cortical hypoconnectivity, apparent during loss of consciousness. Finally, we show that while clustering is increased during loss of consciousness, as recently suggested, it also remains significantly elevated during wakefulness recovery. Conversely, the characteristic path length of brain networks (i.e., the average functional distance between any two regions of the brain) appears significantly increased only during loss of consciousness, marking a decrease of global information-processing efficiency uniquely associated with unconsciousness. These findings suggest that propofol-induced loss of consciousness is mainly tied to cortico-cortical and not thalamo-cortical mechanisms, and that decreased efficiency of information flow is the main feature differentiating the conscious from the unconscious brain.
Changes in Effective Connectivity by Propofol Sedation
Francisco Gómez, Christophe Phillips, Andrea Soddu, Melanie Boly, Pierre Boveroux, Audrey Vanhaudenhuyse, Marie-Aurélie Bruno, Olivia Gosseries, Vincent Bonhomme, Steven Laureys, Quentin Noirhomme
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0071370
Abstract: Mechanisms of propofol-induced loss of consciousness remain poorly understood. Recent fMRI studies have shown decreases in functional connectivity during unconsciousness induced by this anesthetic agent. Functional connectivity does not provide information of directional changes in the dynamics observed during unconsciousness. The aim of the present study was to investigate, in healthy humans during an auditory task, the changes in effective connectivity resulting from propofol induced loss of consciousness. We used Dynamic Causal Modeling for fMRI (fMRI-DCM) to assess how causal connectivity is influenced by the anesthetic agent in the auditory system. Our results suggest that the dynamic observed in the auditory system during unconsciousness induced by propofol, can result in a mixture of two effects: a local inhibitory connectivity increase and a decrease in the effective connectivity in sensory cortices.
Detection of Alveolar Fibrocytes in Idiopathic Pulmonary Fibrosis and Systemic Sclerosis
Raphael Borie, Christophe Quesnel, Sophie Phin, Marie-Pierre Debray, Joelle Marchal-Somme, Kiet Tiev, Marcel Bonay, Aurélie Fabre, Paul Soler, Monique Dehoux, Bruno Crestani
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0053736
Abstract: Background Fibrocytes are circulating precursors for fibroblasts. Blood fibrocytes are increased in patients with idiopathic pulmonary fibrosis (IPF). The aim of this study was to determine whether alveolar fibrocytes are detected in broncho-alveolar lavage (BAL), to identify their prognostic value, and their potential association with culture of fibroblasts from BAL. Methods We quantified fibrocytes in BAL from 26 patients with IPF, 9 patients with Systemic Sclerosis(SSc)-interstitial lung disease (ILD), and 11 controls. BAL cells were cultured to isolate alveolar fibroblasts. Results Fibrocytes were detected in BAL in 14/26 IPF (54%) and 5/9 SSc patients (55%), and never in controls. Fibrocytes were in median 2.5% [0.4–19.7] and 3.0% [2.7–3.7] of BAL cells in IPF and SSc-ILD patients respectively. In IPF patients, the number of alveolar fibrocytes was correlated with the number of alveolar macrophages and was associated with a less severe disease but not with a better outcome. Fibroblasts were cultured from BAL in 12/26 IPF (46%), 5/9 SSc-ILD (65%) and never in controls. The detection of BAL fibrocytes did not predict a positive culture of fibroblasts. Conclusion Fibrocytes were detected in BAL fluid in about half of the patients with IPF and SSc-ILD. Their number was associated with less severe disease in IPF patients and did not associate with the capacity to grow fibroblasts from BAL fluid.
Energy Values of Registered Corn Forage Hybrids in France over the Last 20 Years Rose in a Context of Maintained Yield Increase  [PDF]
Aurélie Baldy, Marie-Pierre Jacquemot, Yves Griveau, Cyril Bauland, Matthieu Reymond, Valérie Mechin
American Journal of Plant Sciences (AJPS) , 2017, DOI: 10.4236/ajps.2017.86099
Abstract: The cultivation of corn silage has developed in France since the 1970s to reach 1.5 million of hectares nowadays. Since 1998, a feeding value criterion (namely UFL for “Unité Fourrage Laitière”) has been taken into account to register forage varieties in the French forage maize hybrids catalog in addition to other criteria related to plant agronomical performances such as yield, earliness and lodging resistance. It is frequently stated that the improvement of plant’s agronomic performances would led to a decline in forage energy value. Decline of “Unité Fourrage Laitière” values has been repeatedly reported and the expected increase was not yet visible in 2002. In the present study, a set 47 early and mid-early hybrids commercialized in France between 1958 and 2015 has been cultivated in 3 locations in France. “Unité Fourrage Laitière” values and yield have been estimated in order to shed light on the evolution of feeding value criteria during this period and to conclude on the evolution of “Unité Fourrage Laitière” values since the introduction of this criterion for registration. Results obtained in our study demonstrated a recent rise in “Unité Fourrage Laitière” value in a context of strong yield increase. This increase was not necessarily attributable to high cob proportion in the harvested silage. Breeder’s work since the 2000’s has succeeded to offer hybrids that recover “Unité Fourrage Laitière” values similar to the ones of hybrids from the 1960’s (Royal, 1960, 91 UFL/100
Impact of the Normalized Copy Number of BCR-ABL Transcript upon Diagnosis on Prognosis in CML Patients Treated with Imatinib-Mesylate  [PDF]
Christophe Martinaud, Aurélie Mayet, Sophie Bousquet, Nathalie Beaufils, Jean Gabert, Sophie Raynaud, Marie-Joelle Mozziconacci
Open Journal of Blood Diseases (OJBD) , 2011, DOI: 10.4236/ojbd.2011.12004
Abstract: Quantification of the BCR-ABL transcript is recommended to follow-up CML patients treated by imatinib mesylate (IM). Results are expressed as a normalized copy number (NCN) of BCR-ABL. We studied a cohort of 98 CML patients under IM as a first treatment and monitored by RQ-PCR after 12, 18 and 24 months according to the European LeukemiaNet recommendations. Our results support the hypothesis of an independent correlation between BCR-ABL NCN at diagnosis and major molecular response at 18 and 24 months in an inverse relationship. We also highlighted the possibility to use the NCN at diagnosis as a warning at diagnosis, and may be useful to identify patients who could benefit of a more rigorous follow-up.
Defects Identification and Effects of Annealing on Lu2(1-x)Y2xSiO5 (LYSO) Single Crystals for Scintillation Application
Samuel Blahuta,Aurélie Bessière,Bruno Viana,Vladimir Ouspenski,Eric Mattmann,Julien Lejay,Didier Gourier
Materials , 2011, DOI: 10.3390/ma4071224
Abstract: The nature, properties and relative concentrations of electronic defects were investigated by Thermoluminescence (TL) in Lu 2(1-x)Y 2xSiO 5 (LYSO) single crystals. Ce and Tb-doped single crystals, grown by the Czochralski technique (CZ), revealed similar traps in TL. LYSO:Ce single crystals were grown by the Floating-Zone technique (FZ) with increasing oxygen concentration in the growth atmosphere. TL intensity is strongly dependent on the oxygen content of the material, and oxygen vacancies are proven to be the main electronic defects in LYSO. The effects of oxidizing and reducing annealing post-treatment on these defects were investigated. While oxidizing treatments efficiently reduce the amount of electronic defects, reducing treatments increase the amount of existing traps. In a thermally assisted tunneling mechanism, the localization of oxygen vacancies around the dopant is discussed. They are shown to be in the close vicinity of the dopant, though not in first neighbor positions.
Effect of [OH-] linkages on luminescent properties of ZnO nanoparticles
Teny Theresa John,K R Priolkar,Aurélie Bessière,P R Sarode,Bruno Viana
Physics , 2011, DOI: 10.1021/jp204504q
Abstract: Optical properties of ZnO nanoparticles prepared from a simple chemical method using sodium zincate bath show strong white light emission. X-ray absorption fine structure studies reveal a completely different local environment around Zn in these ZnO nanoparticles. The observed luminescence properties and local structural changes have been explained on the basis of a linkage between Zn and OH- ions in the surface layers of ZnO nanoparticles.
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