Glutamatergic neurons induce expression of functional glutamatergic synapses in primary myotubes.

The functioning of the nervous system depends upon the specificity of its synaptic contacts. The mechanisms triggering the expression of the appropriate receptors on postsynaptic membrane and the role of the presynaptic partner in the differentiation of postsynaptic structures are little known.To address these questions we cocultured murine primary muscle cells with several glutamatergic neurons, either cortical, cerebellar or hippocampal. Immunofluorescence and electrophysiology analyses revealed that functional excitatory synaptic contacts were formed between glutamatergic neurons and muscle cells. Moreover, immunoprecipitation and immunofluorescence experiments showed that typical anchoring proteins of central excitatory synapses coimmunoprecipitate and colocalize with rapsyn, the acetylcholine receptor anchoring protein at the neuromuscular junction.These results support an important role of the presynaptic partner in the induction and differentiation of the postsynaptic structures

Glutamatergic Reinnervation and Assembly of Glutamatergic Synapses in Adult Rat Skeletal Muscle Occurs at Cholinergic Endplates

After denervation of adult rat abdominal muscles, the postsynaptic apparatus of neuromuscular junctions (NMJs) retains its original architecture and clustering of acetylcholine receptors (AChRs). When descending fibers of the spinal cord are surgically diverted to this muscle by a nerve grafting procedure, supraspinal glutamatergic neurons can innervate muscle fibers and restore motor function; the newly formed NMJs switch from a cholinergic to a glutamatergic-type synapse. We show here that regenerating nerve endings contact the fibers in an area occupied by cholinergic endplates. These NMJs are morphologically indistinguishable from those in controls, but they differ in the subunit composition of AChRs. Moreover, by immunofluorescence and immunoelectron microscopy, new NMJs express glutamatergic synapse markers. The \u3b1-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluR1 partially colocalizes with AChRs, and vesicular glutamate transporter 2 is localized in the presynaptic compartment. Immunoprecipitation analysis of membranes from reinnervated muscle showed that AMPA receptor subunits GluR1 and GluR2 coimmunoprecipitate with rapsyn, the AChR-anchoring protein at the NMJ. Taken together, these results indicate that cholinergic endplates can be targeted by new glutamatergic projections and that the clustering of AMPA receptors occurs there

Attention-Based Deep Learning Framework for Human Activity Recognition with User Adaptation

Sensor-based human activity recognition (HAR) requires to predict the action of a person based on sensor-generated time series data. HAR has attracted major interest in the past few years, thanks to the large number of applications enabled by modern ubiquitous computing devices. While several techniques based on hand-crafted feature engineering have been proposed, the current state-of-the-art is represented by deep learning architectures that automatically obtain high level representations and that use recurrent neural networks (RNNs) to extract temporal dependencies in the input. RNNs have several limitations, in particular in dealing with long-term dependencies. We propose a novel deep learning framework, \algname, based on a purely attention-based mechanism, that overcomes the limitations of the state-of-the-art. We show that our proposed attention-based architecture is considerably more powerful than previous approaches, with an average increment, of more than $7\%$ on the F1 score over the previous best performing model. Furthermore, we consider the problem of personalizing HAR deep learning models, which is of great importance in several applications. We propose a simple and effective transfer-learning based strategy to adapt a model to a specific user, providing an average increment of $6\%$ on the F1 score on the predictions for that user. Our extensive experimental evaluation proves the significantly superior capabilities of our proposed framework over the current state-of-the-art and the effectiveness of our user adaptation technique.Comment: Accepted for publication on the IEEE Sensors Journa

Distribución profunda, aspectos biológicos y ecológicos de Aristeus Antennatus (Risso, 1816) en el Mediterráneo Occidental y Central

[EN] The object of the DESEAS Project, funded by the EC, was to gather preliminary data on the abundance and maximum depth distribution of the rose shrimp Aristeusantennatus in the Mediterranean Sea. An exploratory survey was therefore designed with that goal in mind and conducted on the R/V García del Cid, sampling the maximum depths in three specific areas in the central and western Mediterranean, one off Ibiza (Balearic Islands), one off Calabria (western Ionian Sea), and one off the southern Peloponnesian Peninsula (Gulf of Kalamata, eastern Ionian Sea). The depths sampled ranged from 600 to 4000 m, with specimens of A. antennatus being collected down to 3300 m. There were three distinct boundaries marking the abundance of this species: 1500 m, relatively low abundance (<100 ind km-2). The known population structure of this shrimp species, with increasing proportions of males and juveniles with depth, was also recorded in the deep-sea regions in other areas of the Mediterranean. No evidence of any differences in gonad development or in the presence of spermatophores carried by females was found in any of the three sampling areas. Lastly, a tendency for the relative proportion of juveniles to increase with depth was also observed[ES] El objetivo del proyecto DESEAS, financiado por la CE, fue obtener datos preliminares de abundancia y distribución de profundidad máxima de la gamba rosada Aristeus antennatus en el Mar Mediterráneo. El diseño de la campaña exploratoria fue realizado con este propósito y se desarrolló a bordo del B/O García del Cid. Se realizaron muestreos en las máximas profundidades de tres áreas específicas en el Mediterráneo occidental y central: una cerca de Menorca (Islas Baleares), otra frente a las costas de Calabria (Iónico occidental) y la última al sur de la península del Peloponeso (en el Golfo de Kalamata, Iónico oriental). Las profundidades muestreadas fueron las comprendidas entre 600 y 4000 m, obteniendo individuos de A. antennatus hasta 3300 m. Se detectaron tres niveles de abundancias diferenciados en esta especie: 1500 m, relativamente poco abundante (< 100 ind km-2). En las tres áreas estudiadas se confirmó la estructura de la población conocida hasta el momento, es decir, aumento de la proporción de machos y juveniles con la profundidad. No se encontraron evidencias de diferencias en el desarrollo gonadal o en la presencia de espermatóforos de las hembras entre áreas. Finalmente se observó la existencia de una tendencia en el aumento de la proporción de juveniles con la profundidadThis work was financially supported by the Directorate General Fisheries of the EC as part of the DESEAS survey programme (DGXIV, Study Contract, 2000/39)Peer reviewe

Are Graph Convolutional Networks Fully Exploiting Graph Structure?

Graph Convolutional Networks (GCNs) generalize the idea of deep convolutional networks to graphs, and achieve state-of-the-art results on many graph related tasks. GCNs rely on the graph structure to define an aggregation strategy where each node updates its representation by combining information from its neighbours. In this paper we formalize four levels of structural information injection, and use them to show that GCNs ignore important long-range dependencies embedded in the overall topology of a graph. Our proposal includes a novel regularization technique based on random walks with restart, called RWRReg, which encourages the network to encode long-range information into the node embeddings. RWRReg is further supported by our theoretical analysis, which demonstrates that random walks with restart empower aggregation-based strategies (i.e., the Weisfeiler-Leman algorithm) with long-range information. We conduct an extensive experimental analysis studying the change in performance of several state-of-the-art models given by the four levels of structural information injection, on both transductive and inductive tasks. The results show that the lack of long-range structural information greatly affects performance on all considered models, and that the information extracted by random walks with restart, and exploited by RWRReg, gives an average accuracy improvement of more than $5\%$ on all considered tasks

Physical activity and anodal-transcranial direct current stimulation: a synergistic approach to boost motor cortex plasticity

The application of anodal-transcranial direct current stimulation (A-tDCS) over the primary motor cortex (M1) increases its structural and functional plasticity, as also physical exercise. Combining both interventions has a boosting effect, thus revealing a crucial role of the brain state during stimulation. Although brain slice and anesthetized animal studies support this, further investigation in awake animals is necessary. In the present study, we analyzed the effects of coupling A-tDCS with low-intensity physical activity on the mouse M1 structural and functional plasticity. C57BL/6 mice were monolaterally treated with M1 A-tDCS while walking on a rotarod or at rest. To assess the impact of our interventions, we analyzed both motor cortices for changes in neuronal activation, dendritic spine density, and functional synchronisation as measured by local field potential coherence. The combination of physical activity and M1 stimulation revealed a synergistic interhemispheric effect on cortical activation in both layers II/III and V, not present when using a single type of intervention. These data were accompanied by increased M1-M1 synchrony in the low-theta frequency, a hallmark of motor network activity in mice. Dendritic spine density revealed an effect of the combo, which was significantly higher only in layer II/III, accompanied by increased post-synaptic density protein 95 expression in the same area. Based on our findings, we propose that the efficacy of tDCS hinges on brain state rather than being merely a direct causal factor. The observed outcomes contribute to a deeper comprehension of the mechanisms governing structural and functional reorganisation within the motor cortex under physiological conditions, with potential implications for research on learning, memory, and neurological disorders such as stroke

SizeShiftReg: a Regularization Method for Improving Size-Generalization in Graph Neural Networks

In the past few years, graph neural networks (GNNs) have become the de facto model of choice for graph classification. While, from the theoretical viewpoint, most GNNs can operate on graphs of any size, it is empirically observed that their classification performance degrades when they are applied on graphs with sizes that differ from those in the training data. Previous works have tried to tackle this issue in graph classification by providing the model with inductive biases derived from assumptions on the generative process of the graphs, or by requiring access to graphs from the test domain. The first strategy is tied to the quality of the assumptions made for the generative process, and requires the use of specific models designed after the explicit definition of the generative process of the data, leaving open the question of how to improve the performance of generic GNN models in general settings. On the other hand, the second strategy can be applied to any GNN, but requires access to information that is not always easy to obtain. In this work we consider the scenario in which we only have access to the training data, and we propose a regularization strategy that can be applied to any GNN to improve its generalization capabilities from smaller to larger graphs without requiring access to the test data. Our regularization is based on the idea of simulating a shift in the size of the training graphs using coarsening techniques, and enforcing the model to be robust to such a shift. Experimental results on standard datasets show that popular GNN models, trained on the 50% smallest graphs in the dataset and tested on the 10% largest graphs, obtain performance improvements of up to 30% when trained with our regularization strategy

Vasculogenesi, anomalie di crescita vascolari della placenta e cardiopatie congenite: uno studio sperimentale, multidisciplinare e multicentrico volto ad individuare una correlazione ad oggi non nota

Introduzione: Le Cardiopatie Congenite (CC), sono le anomalie congenite pi\uf9 frequenti alla nascita, con un'incidenza di 1 su 100 nati vivi. La placenta \ue8 l'organo fetale pi\uf9 complesso, in grado di garantire lo sviluppo e la crescita fetale durante la gravidanza. Sebbene lo sviluppo della placenta e del cuore avvenga in parallelo, il rapporto tra questi due organi risulta sconosciuto e trattato solo di recente. Metodi: Abbiamo condotto uno studio osservazionale retrospettivo, includendo i pazienti nati esclusivamente presso l'ospedale G. Gaslini, tra gennaio 2014 e marzo 2018 con una diagnosi prenatale di CC e un\u2019analisi anatomopatologica della placenta, per un totale di 151 pazienti. I feti affetti da CC sono stati divisi in 5 categorie, basate sulla fisiologia cardiovascolare, come segue: (1) ventricolo singolo con ostruzione aortica, (2) ventricolo singolo con ostruzione polmonare, (3) due ventricoli emodinamicamente instabili, (4) trasposizione delle grandi arterie, (5) due ventricoli emodinamicamente stabili. Per ogni paziente, sono stati considerati i seguenti dati: peso placentare assoluto, alterazioni macroscopiche e vascolari del cordone ombelicale, indice di massa corporea materna (BMI), genere, restrizione di crescita intrauterina fetale e neonatale (IUGR), anomalie extracardiache, procedura chirurgica o percutanea nel periodo neonatale. Per l\u2019analisi statistica \ue8 stato utilizzato il test esatto di Fisher, con il quale abbiamo studiato il rapporto di dipendenza fra una specifica variabile e le CC; un p &lt;0,05 \ue8 stato ritenuto significativo per la dipendenza. Risultati: Solo quattro variabili hanno mostrato una significativit\ue0 scientifica: l'intervento neonatale (p = 0,000008), le anomalie associate extracardiache (p = 0,012), l'edema del cordone ombelicale (p = 0,007) e il genere (p = 0,015). Nonostante avessimo riscontrato un'alta incidenza di inserimento anomalo del cordone ombelicale nelle placente di neonati cardiopatici, il risultato dell\u2019analisi di Fisher non ha dimostrato alcuna dipendenza tra i gruppi CC e questa variabile (p = 0,379). Conclusione: Dallo studio dei nostri risultati, non riteniamo che il peso della placenta possa predire la diagnosi di CC, come precedentemente riportato in letteratura. Sulla base della nostra esperienza, non possiamo considerare l'inserimento anormale del cordone come un fattore ad alto rischio per CC. Pertanto, non riteniamo necessario ampliare la metodica di screening ecografico mediante l\u2019analisi della modalit\ue0 di inserimento del cordone. Contrariamente, la presenza di edema del cordone ombelicale \ue8 risultata dipendente dalle CC quindi, potrebbe essere ritenuto un fattore di rischio per CC. Analogamente, anche il genere \ue8 risultato dipendente dalle CC, con una forte associazione fra il sesso maschile e le CC Mayor. Per il futuro, riteniamo necessario implementare lo studio con l\u2019inserimento di un gruppo di controllo e con l\u2019inclusione di altre variabili cliniche e strumentali del feto e della placenta.Introduction: Congenital heart diseases (CHD) are the most frequent congenital anomalies at birth, with an incidence of 1 in 100 live births. The placenta is the most complex fetal organ, responsible of fetal development and growth during pregnancy. Although the development of the placenta and heart occurs in parallel, the relationship between these two organs is unknown and only recently elucidated. Methods: We conducted a retrospective observational study, including patients born exclusively at the G. Gaslini hospital, between January 2014 and March 2018 with a prenatal diagnosis of CHD and an anatomopathological analysis of the placenta, for a total of 151 patients. Fetuses with CHD Mayor were divided into 5 categories, based on cardiovascular physiology, as follows: (1) single ventricle with aortic obstruction, (2) single ventricle with pulmonary obstruction, (3) two hemodynamically unstable ventricles, (4) transposition of the great arteries, (5) two hemodynamically stable ventricles. For each patient, the following data were considered: absolute placental weight, macroscopic and vascular alterations of the umbilical cord, maternal body mass index (BMI), gender, fetal and neonatal intrauterine growth restriction (IUGR), extracardiac anomalies, surgical procedure or percutaneous in the neonatal period. For statistical analysis, the Fisher test was used, with which we studied the dependency ratio between a specific variable and the CHD; a p &lt;0.05 was considered significant. Results: Only four variables showed scientific significance: neonatal surgery (p = 0.000008), associated extracardiac anomalies (p = 0.012), umbilical cord edema (p = 0.007) and gender (p = 0.015). Although we had found a high incidence of abnormal insertion of the umbilical cord in the placentas of heart disease infants, the result of Fisher's analysis showed no dependence between the CHD groups and this variable (p = 0.379). Conclusion: From the analysis of our results, we do not believe that the weight of the placenta can predict the diagnosis of CHD, as previously reported in the literature. Based on our experience, we cannot consider abnormal cord insertion as a high risk factor for CHD. Therefore, we do not consider it necessary to expand the ultrasound screening method by analyzing the cord insertion method. Conversely, the presence of edema of the umbilical cord was found to be CHD dependent therefore, it could be considered a risk factor for CHD. Similarly, gender was also dependent on CHD, with a strong association between the male sex and CHD Mayor. For the future, we believe it is necessary to implement the study with the inclusion of a control group and with the inclusion of other clinical and instrumental variables of the fetus and placenta