Sequential Reinstatement of Neocortical Activity during Slow Oscillations Depends on Cells’ Global Activity

During Slow Wave Sleep (SWS), cortical activity is dominated by endogenous processes modulated by slow oscillations (0.1–1 Hz): cell ensembles fluctuate between states of sustained activity (UP states) and silent epochs (DOWN states). We investigate here the temporal structure of ensemble activity during UP states by means of multiple single unit recordings in the prefrontal cortex of naturally sleeping rats. As previously shown, the firing rate of each PFC cell peaks at a distinct time lag after the DOWN/UP transition in a consistent order. We show here that, conversely, the latency of the first spike after the UP state onset depends primarily on the session-averaged firing rates of cells (which can be considered as an indirect measure of their intrinsic excitability). This latency can be explained by a simple homogeneous process (Poisson model) of cell firing, with sleep averaged firing rates employed as parameters. Thus, at DOWN/UP transitions, neurons are affected both by a slow process, possibly originating in the cortical network, modulating the time course of firing for each cell, and by a fast, relatively stereotyped reinstatement of activity, related mostly to global activity levels

Coherent Theta Oscillations and Reorganization of Spike Timing in the Hippocampal- Prefrontal Network upon Learning

To study the interplay between hippocampus and medial prefrontal cortex (Pfc) and its importance for learning and memory consolidation, we measured the coherence in theta oscillations between these two structures in rats learning new rules on a Y maze. Coherence peaked at the choice point, most strongly after task rule acquisition. Simultaneously, Pfc pyramidal neurons reorganized their phase, concentrating at hippocampal theta trough, and synchronous cell assemblies emerged. This synchronous state may result from increased inhibition exerted by interneurons on pyramidal cells, as measured by cross-correlation, and could be modulated by dopamine: we found similar hippocampal-Pfc theta coherence increases and neuronal phase shifts following local administration of dopamine in Pfc of anesthetized rats. Pfc cell assemblies emerging during high coherence were preferentially replayed during subsequent sleep, concurrent with hippocampal sharp waves. Thus, hippocampal/prefrontal coherence could lead to synchronization of reward predicting activity in prefrontal networks, tagging it for subsequent memory consolidation.European Commission (Contract FP6-IST 027819)European Commission (Contract FP6-IST-027140)European Commission (Contract FP6-IST-027017

Prise en charge de l’hyperparathyroidie primaire : a propos de 25 cas et revue de la littérature

Objectif : Les auteurs rapportent leur expérience dans la prise en charge de l’hyperparathyroïdie primaire (HPTP) et comparent leurs résultats par rapport aux données de la littérature en discutant les avantages potentiels des différentes techniques chirurgicales. Matériel et méthodes : Il s’agit d’une étude rétrospective à propos de 25 patients colligés sur 8 ans (1998-2005). Tous les patients ont bénéficié d’une échographie cervicale, d’un bilan rénal et d’un dosage de la calcémie et de la parathormonémie (PTH). Une TDM cervicale a été pratiquée dans 8 cas et une IRM dans 3 cas. Une scintigraphie à la tétrofosmine a été réalisée dans 10 cas, et à double isotope (thallium 201-technétium 99) dans 2 cas. Une cervicotomie avec exploration bilatérale systématique des 2 loges thyroïdiennes a été pratiquée dans tous les cas. En postopératoire, la surveillance a été clinique et biologique avec un recul moyen de 22 mois. Résultats : La calcémie était élevée chez 23 patients et la PTH dans tous les cas. L’échographie a détecté une hypertrophie d’une glande parathyroïde chez 14 patients (56%) et de 2 glandes chez 1 seul patient. La TDM cervicale a permis de localiser la lésion dans 5 cas. L’IRM était normale dans les 3 cas où elle a été pratiquée. La scintigraphie a montré une hyperfixation dans 8 cas. Une exérèse d’adénomes a été pratiquée dans 92% et une parathyroïdectomie subtotale dans 8% des cas. Le taux de guérison était de 88% après première intervention. Une reprise chirurgicale avec exérèse d’adénome a été pratiquée chez 2 patients (8%). Par ailleurs aucune complication n’a été notée en postopératoire. Conclusion : La chirurgie parathyroïdienne classique donne de bons résultats avec des taux de guérison élevés et un taux de morbidité global faible. Ces résultats sont comparables avec ceux de la littérature. La chirurgie mini-invasive donne des résultats semblables mais impose des impératifs techniques, une imagerie performante et des patients rigoureusement sélectionnés.Mots-clés : hypercalcémie, hyperparathyroïdie primaire,  hyperparathormonémie, chirurgie parathyroïdienn

Leiomyome agressif naso-sinusien : a propos d’un cas et revue de la litterature

Introduction : Les léiomyomes sont des tumeurs bénignes issues des fibres musculaires lisses. La localisation au niveau des cavités nasosinusiennes est très rare.Cas clinique : Il s’agit d’une patiente âgée de 59 ans, qui a consulté pour obstruction nasale et épistaxis gauches. L’endoscopie nasale a montré une formation comblant totalement la fosse nasale gauche. L’imagerie (TDM, IRM) a objectivé un volumineux processus expansif tissulaire naso-ethmoïdo-maxillaire, avec extension intra-orbitaire et endocrânienne. La biopsie confirmé qu’il s’agit d’un léiomyome à localisation nasosinusienne. La patiente a été opérée par voie paralatéronasale élargie. Elle a eu une exérèse tumorale complète et une reconstruction de la perte de substance osseuse par autogreffe. Les suites opératoires étaient simples. Aucune récidive n’a été notée après un recul de 1 an.Conclusion : La localisation nasosinusienne du léiomyome est très rare. L’imagerie est indispensable dans le cadre du bilan d’extension loco-régional. Seul une exérèse chirurgicale complète permettra d’éviter toute récidive aussi bien à court qu’à long terme.Mots-clés : léiomyome, fosses nasales, sinus, tomodensitométrie, imagerie par résonance magnétique, chirurgie sinusienneIntroduction: Leiomyomas are benign tumors arising from smooth muscle fibers. The location at the sinonasal cavities is very rare.Case report: This is a female patient aged 59, who consulted for left nasal obstruction and epistaxis. Nasal endoscopy showed a tumor completely filling the left nasal cavity. Imaging (CT, MRI) has objectified a large expansive tissularnaso-maxillary-ethmoidal process with intraorbital and intracranial extension. The biopsy confirmed that this was a leiomyoma with sinonasal localization. The patient was operated by extended paralatéronasale approach. She had a complete tumor resection and reconstruction of the bone defect with autograft. The postoperative course was uneventful. No recurrence was observed after a follow-up period of 1 year.Conclusion: The sinonasal location of leiomyoma is very rare. Imaging is essential for locoregional staging. Only a complete surgical resection will prevent any recurrence both in short and long term.Keywords : leiomyoma, nasal fossae, sinus, computed tomography, magnetic resonance imaging, sinusal surger

Place et limites de la chirurgie endonasale dans le traitement des mucoceles sinusiennes

Objectif : Préciser les indications et les limites de la chirurgie endonasale dans le traitement des mucocèles sinusiennes.Matériel et méthodes : Il s’agit d’une étude rétrospective à propos de 15 patients colligés sur 13 ans (1994-2006). Tous les patients ont bénéficié d’une endoscopie nasale et d’une TDM du massif facial. Une IRM a été pratiquée dans 10 cas. Le traitement chirurgical comportait une marsupialisation ou une exérèse de la mucocèle. Les voies d’abord étaient endonasales, externes ou combinées, en fonction de l’extension ou de la topographie des lésions. La surveillance en postopératoire a été clinique et radiologique. Résultats : La TDM a montré une atteinte ethmoïdo-frontale (6 cas), maxillaire (5 cas), ethmoïdale isolée (2 cas), frontale isolée (1 cas) et sphénoïdale (1 cas). L’IRM a montré une extension orbitaire dans 7 cas et endocrânienne dans 3 cas. La voie d’abord chirurgicale était endonasale exclusive dans 12 cas. Une voie combinée (endonasale et externe) a été nécessaire chez un patient ayant une atteinte frontale isolée et un autre ayant une atteinte ethmoïdo-frontale. Un patient ayant une mucocèle maxillaire latérale a été opéré par voie de Caldwell-Luc. Aucune récidive n’a été notée avec un recul moyen de 14 mois. Conclusion : La chirurgie endonasale représente la technique de choix dans le traitement des mucocèles sinusiennes et donne de bons résultats à long terme. Le siège et l’extension des mucocèles représentent les principaux facteurs déterminants dans le choix de la voie d’abord

Les stenoses tracheales acquises: Experiencede l’hopitalhabibthameur

Introduction: Acquired tracheal stenoses represent rare but serious disease. They are often secondary to inappropriate management of patients under artificial ventilation. The goal of this study is to evaluate our results in the management of these stenoses and to assess the benefits and the limits different therapeutic means.Materials and methods : We carry a retrospective study about 18 cases of acquired tracheal stenoses treated and followed in our department between 1999 and 2006. Initial endoscopic and radiological explorations have been performed in all cases. Treatment of the stenoses was medical, endoscopic and/or surgical. Follow-up was clinical and endoscopicwith a mean period of 22 months.Results : All patients were victims of pathology needing intubation. Tracheotomy was performed after intubation in 50% of cases after a mean period of 12 days (5-20 days). Dyspnea and dysphonia were the major functional symptoms. Initial endoscopy showed a double tracheal stenosis in one case. Stenoses were initialy fibrous in 72.2% of cases and evolutivein 27.8% of cases. CT scan performed in 12 cases and MRI in 2 others allowed to better study stenosis characteristics. RFE was performed in 6 cases and showed an obstructive syndrome in all of them. All patients received medical treatment. Before a definitive treatment, dilatation was performed in 11 cases (61%) and stenting in one other (5.6%). Laser diode therapy was used in 11 patients including 2 cases having postoperative recurrence. Tracheal resection and reconstruction wasperformed in 11 cases (61%) having extensive and severe stenoses with involvement of tracheal cartilage.Conclusion : Acquired tracheal stenoses represent a serious complication with high morbidity. If tracheal resection and reconstruction remains the gold standard treatment, endoscopy represents now a major alternative in their management. Nevertheless, prevention should be considered, given that most stenoses are iatrogenic due to traumatic or prolongedintubations

Collaborative database to track Mass Mortality Events in the Mediterranean Sea

Anthropogenic climate change, and global warming in particular, has strong and increasing impacts on marine ecosystems (Poloczanska et al., 2013; Halpern et al., 2015; Smale et al., 2019). The Mediterranean Sea is considered a marine biodiversity hotspot contributing to more than 7% of world\u2019s marine biodiversity including a high percentage of endemic species (Coll et al., 2010). The Mediterranean region is a climate change hotspot, where the respective impacts of warming are very pronounced and relatively well documented (Cramer et al., 2018). One of the major impacts of sea surface temperature rise in the marine coastal ecosystems is the occurrence of mass mortality events (MMEs). The first evidences of this phenomenon dated from the first half of \u201980 years affecting the Western Mediterranean and the Aegean Sea (Harmelin, 1984; Bavestrello and Boero, 1986; Gaino and Pronzato, 1989; Voultsiadou et al., 2011). The most impressive phenomenon happened in 1999 when an unprecedented large scale MME impacted populations of more than 30 species from different phyla along the French and Italian coasts (Cerrano et al., 2000; Perez et al., 2000). Following this event, several other large scale MMEs have been reported, along with numerous other minor ones, which are usually more restricted in geographic extend and/or number of affected species (Garrabou et al., 2009; Rivetti et al., 2014; Marb\ue0 et al., 2015; Rubio-Portillo et al., 2016, authors\u2019 personal observations). These events have generally been associated with strong and recurrent marine heat waves (Crisci et al., 2011; Kersting et al., 2013; Turicchia et al., 2018; Bensoussan et al., 2019) which are becoming more frequent globally (Smale et al., 2019). Both field observations and future projections using Regional Coupled Models (Adloff et al., 2015; Darmaraki et al., 2019) show the increase in Mediterranean sea surface temperature, with more frequent occurrence of extreme ocean warming events. As a result, new MMEs are expected during the coming years. To date, despite the efforts, neither updated nor comprehensive information can support scientific analysis of mortality events at a Mediterranean regional scale. Such information is vital to guide management and conservation strategies that can then inform adaptive management schemes that aim to face the impacts of climate change

Principal component analysis of ensemble recordings reveals cell assemblies at high temporal resolution

Simultaneous recordings of many single neurons reveals unique insights into network processing spanning the timescale from single spikes to global oscillations. Neurons dynamically self-organize in subgroups of coactivated elements referred to as cell assemblies. Furthermore, these cell assemblies are reactivated, or replayed, preferentially during subsequent rest or sleep episodes, a proposed mechanism for memory trace consolidation. Here we employ Principal Component Analysis to isolate such patterns of neural activity. In addition, a measure is developed to quantify the similarity of instantaneous activity with a template pattern, and we derive theoretical distributions for the null hypothesis of no correlation between spike trains, allowing one to evaluate the statistical significance of instantaneous coactivations. Hence, when applied in an epoch different from the one where the patterns were identified, (e.g. subsequent sleep) this measure allows to identify times and intensities of reactivation. The distribution of this measure provides information on the dynamics of reactivation events: in sleep these occur as transients rather than as a continuous process

The Role of Serotonin in the Regulation of Patience and Impulsivity

Classic theories suggest that central serotonergic neurons are involved in the behavioral inhibition that is associated with the prediction of negative rewards or punishment. Failed behavioral inhibition can cause impulsive behaviors. However, the behavioral inhibition that results from predicting punishment is not sufficient to explain some forms of impulsive behavior. In this article, we propose that the forebrain serotonergic system is involved in “waiting to avoid punishment” for future punishments and “waiting to obtain reward” for future rewards. Recently, we have found that serotonergic neurons increase their tonic firing rate when rats await food and water rewards and conditioned reinforcer tones. The rate of tonic firing during the delay period was significantly higher when rats were waiting for rewards than for tones, and rats were unable to wait as long for tones as for rewards. These results suggest that increased serotonergic neuronal firing facilitates waiting behavior when there is the prospect of a forthcoming reward and that serotonergic activation contributes to the patience that allows rats to wait longer. We propose a working hypothesis to explain how the serotonergic system regulates patience while waiting for future rewards

Unpublished Mediterranean and Black Sea records of marine alien, cryptogenic, and neonative species

To enrich spatio-temporal information on the distribution of alien, cryptogenic, and neonative species in the Mediterranean and the Black Sea, a collective effort by 173 marine scientists was made to provide unpublished records and make them open access to the scientific community. Through this effort, we collected and harmonized a dataset of 12,649 records. It includes 247 taxa, of which 217 are Animalia, 25 Plantae and 5 Chromista, from 23 countries surrounding the Mediterranean and the Black Sea. Chordata was the most abundant taxonomic group, followed by Arthropoda, Mollusca, and Annelida. In terms of species records, Siganus luridus, Siganus rivulatus, Saurida lessepsianus, Pterois miles, Upeneus moluccensis, Charybdis (Archias) longicollis, and Caulerpa cylindracea were the most numerous. The temporal distribution of the records ranges from 1973 to 2022, with 44% of the records in 2020–2021. Lethrinus borbonicus is reported for the first time in the Mediterranean Sea, while Pomatoschistus quagga, Caulerpa cylindracea, Grateloupia turuturu, and Misophria pallida are first records for the Black Sea; Kapraunia schneideri is recorded for the second time in the Mediterranean and for the first time in Israel; Prionospio depauperata and Pseudonereis anomala are reported for the first time from the Sea of Marmara. Many first country records are also included, namely: Amathia verticillata (Montenegro), Ampithoe valida (Italy), Antithamnion amphigeneum (Greece), Clavelina oblonga (Tunisia and Slovenia), Dendostrea cf. folium (Syria), Epinephelus fasciatus (Tunisia), Ganonema farinosum (Montenegro), Macrorhynchia philippina (Tunisia), Marenzelleria neglecta (Romania), Paratapes textilis (Tunisia), and Botrylloides diegensis (Tunisia)