88 research outputs found

    Using a virtual cortical module implementing a neural field model to modulate brain rhythms in Parkinson’s disease

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    We propose a new method for selective modulation of cortical rhythms based on neural field theory, in which the activity of a cortical area is extensively monitored using a two-dimensional microelectrode array. The example of Parkinson’s disease illustrates the proposed method, in which a neural field model is assumed to accurately describe experimentally recorded activity. In addition, we propose a new closed-loop stimulation signal that is both space- and time- dependent. This method is especially designed to specifically modulate a targeted brain rhythm, without interfering with other rhythms. A new class of neuroprosthetic devices is also proposed, in which the multielectrode array is seen as an artificial neural network interacting with biological tissue. Such a bio-inspired approach may provide a solution to optimize interactions between the stimulation device and the cortex aiming to attenuate or augment specific cortical rhythms. The next step will be to validate this new approach experimentally in patients with Parkinson’s disease

    Is activation of the vestibular system by electromagnetic induction a possibility in an MRI context?

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    In recent years, an increasing number of studies have discussed the mechanisms of vestibular activation in strong magnetic field settings such as occur in a magnetic resonance imaging scanner environment. Amid the different hypotheses, the Lorentz force explanation currently stands out as the most plausible mechanism, as evidenced by activation of the vestibulo‐ocular reflex. Other hypotheses have largely been discarded. Nonetheless, both human data and computational modeling suggest that electromagnetic induction could be a valid mechanism which may coexist alongside the Lorentz force. To further investigate the induction hypothesis, we provide, herein, a first of its kind dosimetric analysis to estimate the induced electric fields at the vestibular system and compare them with what galvanic vestibular stimulation would generate. We found that electric fields strengths from induction match galvanic vestibular stimulation strengths generating vestibular responses. This review examines the evidence in support of electromagnetic induction of vestibular responses, and whether movement‐induced time‐varying magnetic fields should be further considered and investigated

    Community coverage of an antimalarial combination of artesunate and amodiaquine in Makamba Province, Burundi, nine months after its introduction

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    BACKGROUND: In 2003, artesunate-amodiaquine (AS+AQ) was introduced as the new first-line treatment for uncomplicated malaria in Burundi. After confirmed diagnosis, treatment was delivered at subsidized prices in public health centres. Nine months after its implementation a study was carried out to assess whether children below five years of age with uncomplicated malaria were actually receiving AS+AQ. METHODS: A community-based study was conducted in Makamba province. Randomly selected households containing one or more children under five with reported fever onset within fourteen days before the study date were eligible. Case-management information was collected based on caregiver recall. A case definition of symptomatic malaria from observations of children presenting a confirmed malaria episode on the day of the survey was developed. Based on this definition, those children who had probable malaria among those with fever onset in the 14 days prior to the study were identified retrospectively. Treatment coverage with AS+AQ was then estimated among these probable malaria cases. RESULTS: Out of 195 children with fever on the day of the study, 92 were confirmed as true malaria cases and 103 tested negative. The combination of 'loss of appetite', 'sweating', 'shivering' and 'intermittent fever' yielded the highest possible positive predictive value, and was chosen as the case definition of malaria. Out of 526 children who had had fever 14 days prior to the survey, 165 (31.4%) were defined as probable malaria cases using this definition. Among them, 20 (14.1%) had been treated with AS+AQ, 10 with quinine (5%), 68 (41%) received non-malaria treatments, and 67 got traditional treatment or nothing (39.9%). Most people sought treatment from public health centres (23/99) followed by private clinics (15/99, 14.1%). The median price paid for AS+AQ was 0.5 US$. CONCLUSION: AS+AQ was the most common treatment for patients with probable malaria at public health centres, but coverage was low due to low health centre utilisation and apparently inappropriate prescribing. In addition, AS+AQ was given to patients at a price ten times higher than the subsidized price. The availability and proper use of ACTs should be monitored and maximized after their introduction in order to have a significant impact on the burden of malaria

    Effets d'un champ magnétique d'extrêmement basse fréquence sur les micro-mouvements segmentaires humains

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    MONTPELLIER-BU Médecine UPM (341722108) / SudocMONTPELLIER-BU STAPS (341722109) / SudocMONTPELLIER-BU Médecine (341722104) / SudocSudocFranceF

    Écrire en diplomatie : l'agent général de France à Madrid et le monde hispanique (1702-1793)

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    Compte-rendu de l'intervention de Sylvain LLORET (Université de Caen Normandie) le 28 septembre 2018 Durant ce séminaire, nous avons pu entendre l'analyse d'une fonction peu connue, mais néanmoins majeure dans la diplomatie franco-espagnole au XVIIIe siècle, celle de l'agent général de la Marine et du Commerce de France à Madrid. Créé en 1702, cet agent hybride, officieux, ni consul ni diplomate, était chargé de coordonner un réseau français d'information marchande en Espagne. Il deva..

    Reconstruction of brain networks involved in magnetophosphene perception using dense electroencephalography

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    International audienceCharacterizing functional brain networks in humans during magnetophosphene perception. Dense electroencephalography (EEG, 128 channels) was performed in N=3 volunteers during high-level (50 mT) magnetic field (MF) exposure. Functional brain networks were reconstructed, at the cortical level from scalp recordings, using the EEG source connectivity method. Magnetophosphene perception appears to consistently activate the right inferior occipito-temporal pathway. This study provides the very first neuroimaging results characterizing magnetophosphene perception in humans. The use of dense-EEG source connectivity is a promising approach in the field of bioelectromagnetics
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