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Reversal learning is widely used to analyze cognitive flexibility and characterize behavioral abnormalities associated with impulsivity and disinhibition. Recent studies using fMRI have focused on regions involved in reversal learning with negative and positive reinforcers. Although the frontal cortex has been consistently implicated in reversal learning, few studies have focused on whether reward and punishment may have different effects on lateral frontal structures in these tasks. During this pilot study on eight healthy subjects, we used functional near infra-red spectroscopy (fNIRS) to characterize brain activity dynamics and differentiate the involvement of frontal structures in learning driven by reward and punishment. We observed functional hemispheric asymmetries between punishment and reward processing by fNIRS following reversal of a learned rule. Moreover, the left dorsolateral prefrontal cortex (l-DLPFC) and inferior frontal gyrus (IFG) were activated under the reward condition only, whereas the orbito-frontal cortex (OFC) was significantly activated under the punishment condition, with a tendency towards activation for the right cortical hemisphere (r-DLPFC and r-IFG). Our results are compatible with the suggestion that the DLPFC is involved in the detection of contingency change. We propose a new representation for reward and punishment, with left lateralization for the reward process. The results of this pilot study provide insights into the indirect neural mechanisms of reversal learning and behavioral flexibility and confirm the use of fNIRS imaging in reversal-learning tasks as a translational strategy, particularly in subjects who cannot undergo fMRI recordings. [ABSTRACT FROM AUTHOR]

Intraventricular Hemorrhage (IVH) is the leading cause of neurological and cognitive impairment in preterm neonates with an incidence that increases with increasing prematurity. In the present study, we tested how preterm neonates with IVH react to external stimulation (i.e. speech syllables). We compared their neural responses measured by electroencephalography (EEG), and hemodynamic responses measured by functional near-infrared spectroscopy (fNIRS), with those of healthy preterms. A neural response to syllables was observed in these infants, but did not induce a vascular response in contrast with healthy neonates. These results clearly demonstrate that the cerebral vascular network in IVH preterm neonates was unable to compensate for the increased metabolism resulting from neuronal activation in response to external stimulation. Optical imaging is thus a sensitive tool to identify altered cerebral hemodynamic in critically ill preterms before behavioral changes are manifested or when only minor abnormalities on other functional monitoring techniques such as EEG are visible. We propose that a multi-modal approach provides unique opportunities for early monitoring of cognitive functions and opens up new possibilities for clinical care and recommended practices by studying the difficulties of the premature brain to adapt to its environment. [ABSTRACT FROM AUTHOR]

Rhythm is a fundamental component of the auditory world, present even during the prenatal life. While there is evidence that some auditory capacities are already present before birth, whether and how the premature neural networks process auditory rhythm is yet not known. We investigated the neural response of premature neonates at 30–34 weeks gestational age to violations from rhythmic regularities in an auditory sequence using high-resolution electroencephalography and event-related potentials. Unpredicted rhythm violations elicited a fronto-central mismatch response, indicating that the premature neonates detected the rhythmic regularities. Next, we examined the cortical effective connectivity underlying the elicited mismatch response using dynamic causal modeling. We examined the connectivity between cortical sources using a set of 16 generative models that embedded alternate hypotheses about the role of the frontal cortex as well as backward fronto-temporal connection. Our results demonstrated that the processing of rhythm violations was not limited to the primary auditory areas, and as in the case of adults, encompassed a hierarchy of temporo-frontal cortical structures. The result also emphasized the importance of top-down (backward) projections from the frontal cortex in explaining the mismatch response. Our findings demonstrate a sophisticated cortical structure underlying predictive rhythm processing at the onset of the thalamocortical and cortico-cortical circuits, two months before term. [ABSTRACT FROM AUTHOR]

Abstract: Hybrid manufacturing/remanufacturing systems play a key role in implementing closed-loop production systems which have been considered due to increasingly environmental concerns and latent profit of used products. Manufacturing and remanufacturing rates, selling price of new products, and acquisition price of used products are the most critical variables to optimize in such hybrid systems. In this paper, we develop a dynamic production/pricing problem, in which decisions should be made in each period confronting with uncertain demand and return. The manufacturer is able to control the demand and return by adjusting selling price and acquisition price respectively, also she can stock inventories of used and new products to deal with uncertainties. Modeling a nominal profit maximization problem, we go through robust optimization approach to reformulate it for the uncertain case. Final robust optimization model is obtained as a quadratic programming model over discrete periods which can be solved by optimization packages of QP. A numerical example is defined and sensitivity analysis is performed on both basic parameters and parameters associated with uncertainty to create managerial views. [Copyright &y& Elsevier]

Introduction Le cerveau du nouveau-né prématuré subit un processus dynamique de maturation avec la mise en place de générateurs spécifiques au cours de développement. L’activité thêta temporale est l’un des premiers neurobiomarqueurs. Le but de cette étude était de mieux caractériser les localisations des générateurs de ces activités. Méthodes Des électroencéphalographies Haute Résolution (EEGHR) étaient enregistrées chez des prématurés âgés de 26 à 31 semaines d’âge corrigé (sAC), avec 40 à 64 électrodes. La position des électrodes était digitalisée sur 2 modèles de têtes réalistes (29 et 31 sAC). La localisation de source était effectuée, après moyennage pour chaque enfant, par méthode dipolaire. La localisation des sources par méthode dipolaire et MUSIC était effectuée sur les activités thêta après interpolation cubique puis grand moyennage par groupe d’enfants/par hémisphère. Résultats Les EEGHR de 14 prématurés comprenant en moyenne 125 activités thêta étaient analysés. Les générateurs des activités thêta, traitées par groupe d’enfant après moyennage, étaient localisés dans le prolongement du sillon temporal postérieur avec une localisation plus profonde pour les plus jeunes. Les modifications des caractéristiques du modèle de tête (conductivité osseuse, prise en compte du liquide cérébro-spinal) entraînaient des modifications relatives de la position du dipôle temporal. Conclusion Les générateurs des activités thêta temporales étaient localisés dans le prolongement du sillon temporal supérieur en regard du planum temporal dès 26 sAC. Ces biomarqueurs pouvaient correspondre indirectement au rôle de guidance fonctionnelle de la sous plaque afin de préparer la mise en place de la fonction auditive ou langagière corticale. [ABSTRACT FROM AUTHOR]

The non-invasive multimodal analysis of brain function in the premature babies makes it possible to evaluate the implementation of neural networks involved in various functions such as language. The establishment of neural networks is the result of (1) initial genetic factors that participate in the structural and functional development of networks, (2) endogenous stimuli-independent generators, (3) endogenous stimulus-dependent generators and (4) stimuli-dependant activations. Multimodal analysis, magnetic resonance imaging, optical imaging and high-resolution EEG (HR-EEG) source imaging enable the analysis of these initial premature networks. Thus, as early as 28 weeks gestational age, when the thalamocortical afferents start to connect the cortical plate, when perisylvian structures exhibit certain structural asymmetries, the neural network is able to discriminate voice and phonemes with a neural strategy involving synchronization habituation and mismatch in specific areas, suggesting a strong genetic fingerprint in these initial abilities. Using HR-EEG in premature makes it possible to demonstrate that some endogenous generators such as the theta temporal activities located in the posterior part of the temporal planum are stimuli-independent up to 30-week gestational age and probably participate in the early functional wiring of the perisylvian networks involved in language and communication functions. [ABSTRACT FROM AUTHOR]

Electroencephalography is the only clinically available technique that can address the premature neonate normal and pathological functional development week after week. The changes in the electroencephalogram (EEG) result from gradual structural and functional modifications that arise during the last trimester of pregnancy. Here, we review the structural changes over time that underlie the establishment of functional immature neural networks, the impact of certain anatomical specificities (fontanelles, connectivity, etc.) on the EEG, limitations in EEG interpretation, and the utility of high-resolution EEG (HR-EEG) in premature newborns (a promising technique with a high degree of spatiotemporal resolution). In particular, we classify EEG features according to whether they are manifestations of endogenous generators (i.e. theta activities that coalesce with a slow wave or delta brushes) or come from a broader network. Furthermore, we review publications on EEG in premature animals because the data provide a better understanding of what is happening in premature newborns. We then discuss the results and limitations of functional connectivity analyses in premature newborns. Lastly, we report on the magnetoelectroencephalographic studies of brain activity in the fetus. A better understanding of complex interactions at various structural and functional levels during normal neurodevelopment (as assessed using electroencephalography as a benchmark method) might lead to better clinical care and monitoring for premature neonates. [ABSTRACT FROM AUTHOR]

• Breast cancer patients' sera cross-reacts with hydatid cyst wall (HCW) antigens. • HCW immunized rabbits' sera react with the breast cancer cells surface antigens. • Prophylactic immunization with HCW antigens causes significant anti-tumor effects. • Mass spectrometry was used to reveal the reacted proteins with cancer patients' sera. Cancer vaccines have gained lots of attention as the future of cancer treatment. However, poor immunogenicity of tumor-associated antigens often fails to induce an efficient immune response against the tumor. Strange anti-tumor immune responses at the parasite-infected patients due to cross-reactivity have been reported in various studies. Therefore, parasite antigens with significant immunogenicity and high epitope homology with cancer antigens may activate a strong immune response against cancer cells. Herein, the sera of immunized rabbits with the hydatid cyst wall (HCW) antigens were incubated with 4 T1 mammary carcinoma cells to investigate cross-reactivity between the HCW antigens antisera and surface antigens of the breast cancer cells. Also, the SDS-PAGE profile of HCW antigens was prepared and incubated with the breast cancer patients' sera and considerable reactivity was observed between their sera and a specific band (~27/28 kDa) according to Western blotting analyzes. Then, the protein bands with cross-reactivity with breast cancer patients' sera were utilized for prophylactic immunizations of Balb/c mice. The immunoprotective effect of immunization with the HCW antigens caused significant inhibition of 4 T1 breast tumor growth, decrease of metastasis, and enlargement of the tumor-bearing mice survival time in comparison with PBS and pure immune adjuvant injected groups. Mass spectrometry analysis showed that the ~ 27/28 kDa band has numbers of proteins/polypeptides with a high degree of homology with cancer cells antigens which can be the reason for this cross-reactivity and anti-tumor immune response. Taking together, immunization with HCW antigens would be a promising approach in cancer immunotherapy after further investigations. [ABSTRACT FROM AUTHOR]

Objectives To better define the physiopathology of Interictal Epileptic Spikes (IES) and specially: (i) the mechanisms that propel neurons to hypersynchronizations, and (ii) the local and distant dynamic changes of neuronal population activities, we performed a time frequency analysis (TFA) of the surrounding activation of the IES. Methods HD EEG (64 and 128 electrodes) of 19 children (10 males; mean age 9.6 years), with refractory partial epilepsy of different aetiology, were analysed. Two types of IES were analyzed: spikes and poly-spike waves. TFA was performed on HD EEG epochs around the peak of IES (± 1000 ms). TFAs were calculated for frequencies between 4 and 50 Hz. Source localization was then performed from averaging spikes on EEG, from hypersynchronization, and from changes in TFA before hypersynchronization. Results Two time-frequency patterns were individualized: one specific for spike, the other specific for poly-spike-wave. TFA also revealed desynchronization around (before and after) hypersynchronization of IES (± 400 ms) in the epileptogenic zone, as already described in BECTS and in epileptic rats. At the lobar level the source localization was more accurate when performed during desynchronization (100%) than when performed during hypersynchronization (90%), and also than when performed on the peak of IES (74%) in the time domain. Discussion TFA with HD EEG in a children population of refractory partial epilepsy indicate complex changes in the dynamics of neuronal networks, not only during, but also before and after IES that is not specific to the type of epilepsy but to the type of IES. This provides new insight in the mechanism that propels neurons to synchronize. Source localization of IES should be performed during desynchronization, suggesting that the pathological activation already spread before the neuronal hypersynchronization of the IES. [ABSTRACT FROM AUTHOR]

Objectives EEG-HR source localization is a non-invasive method to better delineate the source of the epileptic activity and thus the schema for electrodes implantation. Such source localization method relies on solving an inverse problem. In this study we evaluate the impact of bone conductivity, different head models and filtering, different methods of localization, the number of electrodes and the selection of different parts of the interictal epileptic spike. Methods Two groups of patients were studied. The first group ( n = 13) consists of patients with lesions on the MRI. They were recorded with 64 electrodes. The second group consists of non lesional patient but one ( n = 7) they were recorded with 128 electrodes. In the first group, the impact of bone conductivity, different head models, different filtering, and different methods of localization and the selection of different parts of the interictal spike was evaluate through the Euclidian distance of the resulting dipoles. In the second group, the impact of the number of electrodes ( n = 128/64/32) on the location of the dipole was evaluated. Results The selection of the different parts of the interictal epileptic spikes and the different inverse methods (dipolar/scanning) did not return any significant difference on the source localization. Different filtering and bone conductivities did not significantly impact the localization. The different head model (realistic/realist) had significant impact on the localization of the source. Using 128 electrodes improved significantly the accuracy of the source localization. Conclusion Controlling the different parameters involved in the source localization significantly improve the accuracy of the inverse methods used to delineate the localization of the source of the IES and thus might be helpful to precise the schema of electrodes implantation. [ABSTRACT FROM AUTHOR]