Abnormal cortical sensorimotor activity during “Target” sound detection in subjects with acute acoustic trauma sequelae: an fMRI study

The most common consequences of acute acoustic trauma (AAT) are hearing loss at frequencies above 3 kHz and tinnitus. In this study, we have used functional Magnetic Resonance Imaging (fMRI) to visualize neuronal activation patterns in military adults with AAT and various tinnitus sequelae during an auditory “oddball” attention task. AAT subjects displayed overactivities principally during reflex of target sound detection, in sensorimotor areas and in emotion-related areas such as the insula, anterior cingulate and prefrontal cortex, in premotor area, in cross-modal sensory associative areas, and, interestingly, in a region of the Rolandic operculum that has recently been shown to be involved in tympanic movements due to air pressure. We propose further investigations of this brain area and fine middle ear investigations, because our results might suggest a model in which AAT tinnitus may arise as a proprioceptive illusion caused by abnormal excitability of middle-ear muscle spindles possibly link with the acoustic reflex and associated with emotional and sensorimotor disturbances

Tracking white-matter brain modifications in chronic non-bothersome acoustic trauma tinnitus

Subjective tinnitus is a symptom characterized by the perception of sound with no external acoustic source, most often accompanied by co-morbidities. To date, the specific role of white matter abnormalities related to tinnitus reaches no consensus in the literature. The goal of this study was to explore the structural connectivity related to tinnitus percept per se, thus focusing on a specific population presenting chronic non-bothersome tinnitus of similar etiology (noise induced) without co-morbidities. We acquired diffusion-weighted images with high angular resolution in a homogeneous group of mildly impacted tinnitus participants (n = 19) and their matched controls (n = 19). We focused the study on two subsets of fiber bundles of interest: on one hand, we extracted the acoustic radiation and further included any intersecting fiber bundles; on the other hand, we explored the tracts related to the limbic system. We modeled the diffusion signal using constrained spherical deconvolution. We conducted a deep-learning based tractography segmentation and mapped Apparent Fiber Density (AFD) on the bundles of interest. C, as well as Fractional Anisotropy (FA) and FOD peak amplitude for comparison. Between group statistical comparison was performed along the 27 tracts of interest controlling for confounding hearing loss, tinnitus severity, and duration since onset. We tested a potential correlation with hearing loss, tinnitus duration and tinnitus handicap score along these tracts. In the tinnitus group, we observed increased AFD related to chronic tinnitus percept after acoustic trauma in two main white matter regions. First, in the right hemisphere, in the isthmus between inferior temporal and inferior frontal cortices, in the uncinate fasciculus (UF), and in the inferior fronto-occipital bundle (IFO). Second, in the left hemisphere, underneath the superior parietal region in the thalamo parietal tract and parieto-occipital pontine tract. Between-group differences in the acoustic radiations were not significant with AFD but were with FA. Furthermore, significant correlations with hearing loss were found in the left hemisphere in the inferior longitudinal fasciculus and in the fronto-pontine tract. No additional correlation was found with tinnitus duration nor with tinnitus handicap, as reflected by THI scores. The regions that displayed tinnitus related increased AFD also displayed increased FA. The isthmus of the UF and IFO in the right hemisphere appear to be involved with a number of neuropsychiatric and traumatic disorders confirming the involvement of the limbic system even in chronic non-bothersome tinnitus subjects, potentially suggesting a common pathway between these pathologies. White matter changes underneath the superior parietal cortex found here in tinnitus participants supports the implication of an auditory-somatosensory pathway in tinnitus perception

Communication de l'Académie d'agriculture de France Section des Sciences de la vie | Covid-19 : des vaccins et des traitements issus des biotechnologies végétales sont à l'étude

International audienceL’intensité de la pandémie de Covid-19 causée par le SARS-CoV-2 et la rapidité de sa diffusion exigent de ne négliger aucune piste, notamment en tirant partie des atouts indéniables qu'apportent les biotechnologies végétales. C’est pourquoi l’Académie d’agriculture de France souhaite encourager l’usage des plantes pour développer de nouveaux programmes de recherche en biotechnologie. Dans une note récente des membres de cette Académie attirent l’attention sur des travaux actuels dans ce domaine. C’est ainsi qu’en avril 2020, deux sociétés biopharmaceutiques, Kentucky BioProcessing (Owensboro, Etats-Unis) et Medicago (Québec, Canada) ont fait état de leurs travaux sur l’expression de protéines recombinantes, qui pourraient déboucher sur des vaccins potentiels contre la Covid-19. Ces sociétés utilisent la plante Nicotiana benthamiana, une espèce indigène d'Australie, modèle en biotechnologie pour sa croissance rapide et sa capacité naturelle à exprimer des séquences de gènes d’autres espèces, caractéristiques la rendant bien adaptée à la production de produits biopharmaceutiques. D’autres travaux de biotechnologie végétale sont également menés dans des laboratoires publics et privés, en Chine, Espagne, Etats-Unis, France, Grande-Bretagne et Mexique

Tinnitus Perception in Light of a Parietal Operculo–Insular Involvement: A Review

International audienceIn tinnitus literature, researchers have increasingly been advocating for a clearer distinction between tinnitus perception and tinnitus-related distress. In non-bothersome tinnitus, the perception itself can be more specifically investigated: this has provided a body of evidence, based on resting-state and activation fMRI protocols, highlighting the involvement of regions outside the conventional auditory areas, such as the right parietal operculum. Here, we aim to conduct a review of available investigations of the human parietal operculo–insular subregions conducted at the microscopic, mesoscopic, and macroscopic scales arguing in favor of an auditory–somatosensory cross-talk. Both the previous literature and new results on functional connectivity derived from cortico–cortical evoked potentials show that these subregions present a dense tissue of interconnections and a strong connectivity with auditory and somatosensory areas in the healthy brain. Disrupted integration processes between these modalities may thus result in erroneous perceptions, such as tinnitus. More precisely, we highlight the role of a subregion of the right parietal operculum, known as OP3 according to the Jülich atlas, in the integration of auditory and somatosensory representation of the orofacial muscles in the healthy population. We further discuss how a dysfunction of these muscles could induce hyperactivity in the OP3. The evidence of direct electrical stimulation of this area eliciting auditory hallucinations further suggests its involvement in tinnitus perception. Finally, a small number of neuroimaging studies of therapeutic interventions for tinnitus provide additional evidence of right parietal operculum involvement

Functional Connectivity in Chronic Nonbothersome Tinnitus Following Acoustic Trauma: A Seed-Based Resting-State Functional Magnetic Resonance Imaging Study

International audienc

Asymmetric synthesis of trifluoromethyl-piperidine based ?-aminoacids and of trifluoromethyl-indolizidines.

International audienceThe asymmetric synthesis of trifluoromethyl-piperidine-based g-aminoacids and of indolizidines bearing a trifluoromethyl group is reported. These rarely described compounds are prepared in a highly enantio-enriched form employing as key step an intramolecular Mannich type process, involving an enantiopure Tfm-aminoketal and ethyl oxobutenoate as aldehyde partner. Used strategy together with obtained compounds allows the access to a wide range of Tfm-N-(poly)heterocycles, structures of obvious interest for the research of new bioactive drugs

Pseudomonas putida KT2440 response to nickel or cobalt induced stress by quantitative proteomics

cited By 14International audienceNickel and cobalt are obligate nutrients for the gammaproteobacteria but when present at high concentrations they display toxic effects. These two metals are present in the environment, their origin being either from natural sources or from industrial use. In this study, the effect of inhibitory concentrations of Ni or Co was assessed on the soil bacterium Pseudomonas putida KT2440 using a proteomic approach. The identification of more than 400 spots resulted in the quantification of 160 proteins that underwent significant variations in cells exposed to Co and Ni. This analysis allowed us to depict the cellular response of P. putida cells toward metallic stress. More precisely, the parallel comparison of the two proteomes showed distinct responses of P. putida to Ni or Co toxicity. The most striking effect of Co was revealed by the accumulation of several proteins involved in the defense against oxidative damage, which include proteins involved in the detoxification of the reactive oxygen species, superoxides and peroxides. The up-regulation of the genes encoding these enzymes was confirmed using qRT-PCR. Interestingly, in the Ni-treated samples, sodB, encoding superoxide dismutase, was up-regulated, indicating the apparition of superoxide radicals due to the presence of Ni. However, the most striking effect of Ni was the accumulation of several proteins involved in the synthesis of amino acids. The measurement of the amount of amino acids in Ni-treated cells revealed a strong accumulation of glutamate. © 2013 The Royal Society of Chemistry

Prediction of soman-induced cerebral damage by distortion product otoacoustic emissions.

International audienceThe organophosphorus nerve agent soman is an irreversible cholinesterase (ChE) inhibitor that can produce long-lasting seizures and seizure-related brain damage (SRBD) in which acetylcholine and glutamate are involved. Since these neurotransmitters play a key-role in the auditory function, it was hypothesized that a hearing test may be an efficient way for detecting the central effects of soman intoxication. In the present study, distortion product otoacoustic emissions (DPOAEs), a non-invasive audiometric method, were used in rats administered with soman (70 μg/kg). Four hours post-soman, DPOAE intensities were significantly decreased. They returned to baseline one day later. The amplitude of the temporary drop of the DPOAEs was well related to the severity of the intoxication. The greatest change was recorded in the rats that survived long-lasting convulsions, i.e. those that showed the highest ChE inhibition in brain and severe encephalopathy. Furthermore, the administration, immediately after soman, of a three-drug therapy composed of atropine sulfate, HI-6 and avizafone abolished the convulsions, the transient drop of DPOAEs at 4h and the occurrence of SRBD at 28 h without modifying brain ChE inhibition. This showed that DPOAE change was not directly related to soman-induced inhibition of cerebral ChE but rather to its neuropathological consequences. The present findings strongly suggest that DPOAEs represent a promising non-invasive tool to predict SRBD occurrence in nerve agent poisoning and to control the efficacy of a neuroprotective treatment

Expositions aux niveaux sonores élevés de la musique : recommandations sur les niveaux acceptables

Le HCSP propose des indicateurs de niveau de bruit en vue d’actualiser la réglementation et de garantir la protection des personnes exposées à de la musique amplifiée dans les lieux de loisir (boîtes de nuit, discothèques, salles de spectacle, etc.).Les seuils de dangerosité pour l’oreille dépendent du niveau sonore mesuré en dBA (lequel pondère les fréquences selon la fragilité de l’oreille) et de la durée d’exposition. Ainsi, les risques auditifs sont limités si une exposition à 85 dBA dure moins de 8 heures, ou 4 heures à 88 dBA, ou 2 heures à 91 dBA, ou 15 minutes à 100 dBA, etc.Le HCSP recommande lors des spectacles pour enfants (moins de 18 ans) le respect strict de ces normes.Dans les lieux de loisir pour adultes le HCSP préconise:• l’affichage en continu des niveaux sonores mesurés en dBA sur 15 minutes, associé à l’affichage d’une information sur les niveaux sonores et durées d’écoute sans risque, afin que chacun puisse connaître son niveau d’exposition et de risque potentiel ;• des niveaux sonores moyens de 100 dBA mesurés sur 15 minutes et des niveaux crêtes de 120 dBC à ne pas dépasser ;• la fourniture gratuite de protection auditive et l’offre d’une zone de récupération auditive avec un niveau sonore inférieur à 85 dBA ;• un avertissement pour les femmes enceintes sur les risques de transmission des basses et moyennes fréquences à l’enfant à naître, plus particulièrement fragile au cours des trois derniers mois de grossesse ;• etc.La constitution d’un comité multi-professionnel, pour définir avec précision les domaines d’application couverts, pourrait permettre une meilleure mise en oeuvre de ces propositions.Ce rapport a fait l’objet d’une consultation publique