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Whether maximizing rewards and minimizing punishments rely on distinct brain systems remains debated, given inconsistent results coming from human neuroimaging and animal electrophysiology studies. Bridging the gap across techniques, we recorded intracerebral activity from twenty participants while they performed an instrumental learning task. We found that both reward and punishment prediction errors (PE), estimated from computational modeling of choice behavior, correlate positively with broadband gamma activity (BGA) in several brain regions. In all cases, BGA scaled positively with the outcome (reward or punishment versus nothing) and negatively with the expectation (predictability of reward or punishment). However, reward PE were better signaled in some regions (such as the ventromedial prefrontal and lateral orbitofrontal cortex), and punishment PE in other regions (such as the anterior insula and dorsolateral prefrontal cortex). These regions might therefore belong to brain systems that differentially contribute to the repetition of rewarded choices and the avoidance of punished choices. Whether maximizing rewards and minimizing punishments rely on distinct brain learning systems remains debated. Here, using intracerebral recordings in humans, the authors provide evidence for brain regions differentially engaged in signaling reward and punishment prediction errors that prescribe repetition versus avoidance of past choices.

Reinforcement-based adaptive decision-making is believed to recruit fronto-striatal circuits. A critical node of the fronto-striatal circuit is the thalamus. However, direct evidence of its involvement in human reinforcement learning is lacking. We address this gap by analyzing intra-thalamic electrophysiological recordings from eight participants while they performed a reinforcement learning task. We found that in both the anterior thalamus (ATN) and dorsomedial thalamus (DMTN), low frequency oscillations (LFO, 4-12 Hz) correlated positively with expected value estimated from computational modeling during reward-based learning (after outcome delivery) or punishment-based learning (during the choice process). Furthermore, LFO recorded from ATN/DMTN were also negatively correlated with outcomes so that both components of reward prediction errors were signaled in the human thalamus. The observed differences in the prediction signals between rewarding and punishing conditions shed light on the neural mechanisms underlying action inhibition in punishment avoidance learning. Our results provide insight into the role of thalamus in reinforcement-based decision-making in humans. The functional role of the human thalamus in reinforcement learning is debated. Here, using intra-thalamic recordings in humans, the authors report that thalamic low-frequency oscillations correlate with variables for learning from both reward and punishment.

How human prefrontal and insular regions interact while maximizing rewards and minimizing punishments is unknown. Capitalizing on human intracranial recordings, we demonstrate that the functional specificity toward reward or punishment learning is better disentangled by interactions compared to local representations. Prefrontal and insular cortices display non-selective neural populations to rewards and punishments. Non-selective responses, however, give rise to context-specific interareal interactions. We identify a reward subsystem with redundant interactions between the orbitofrontal and ventromedial prefrontal cortices, with a driving role of the latter. In addition, we find a punishment subsystem with redundant interactions between the insular and dorsolateral cortices, with a driving role of the insula. Finally, switching between reward and punishment learning is mediated by synergistic interactions between the two subsystems. These results provide a unifying explanation of distributed cortical representations and interactions supporting reward and punishment learning.

Ghrelin is a gut-brain peptide hormone, which binds to the growth hormone secretagogue receptor (GHS-R) to regulate a wide variety of biological processes in fish. Despite these prominent physiological roles, no studies have reported the anatomical distribution of preproghrelin transcripts using in situ hybridization in a non-mammalian vertebrate, and its mapping within the different encephalic areas remains unknown. Similarly, no information is available on the possible 24-h variations in the expression of preproghrelin and its receptor in any vertebrate species. The first aim of this study was to investigate the anatomical distribution of ghrelin and GHS-R1a ghrelin receptor subtype in brain and gastrointestinal tract of goldfish (Carassius auratus) using immunohistochemistry and in situ hybridization. Our second aim was to characterize possible daily variations of preproghrelin and ghs-r1 mRNA expression in central and peripheral tissues using real-time reverse transcription-quantitative PCR. Results show ghrelin expression and immunoreactivity in the gastrointestinal tract, with the most abundant signal observed in the mucosal epithelium. These are in agreement with previous findings on mucosal cells as the primary synthesizing site of ghrelin in goldfish. Ghrelin receptor was observed mainly in the hypothalamus with low expression in telencephalon, pineal and cerebellum, and in the same gastrointestinal areas as ghrelin. Daily rhythms in mRNA expression were found for preproghrelin and ghs-r1 in hypothalamus and pituitary with the acrophase occurring at nighttime. Preproghrelin, but not ghs-r1a, displayed a similar daily expression rhythm in the gastrointestinal tract with an amplitude 3-fold higher than the rest of tissues. Together, these results described for the first time in fish the mapping of preproghrelin and ghrelin receptor ghs-r1a in brain and gastrointestinal tract of goldfish, and provide the first evidence for a daily regulation of both genes expression in such locations, suggesting a possible connection between the ghrelinergic and circadian systems in teleosts.

Sewer networks are subjected to degradation, including biodeterioration of materials, in the presence of biogenic sulfuric acid, leading to costly repairs. To ensure durable structures, it is essential to select the best adapted materials. Two cementitious materials based on ordinary Portland cement (OPC) or calcium aluminate cement (CAC), were subjected to biodeterioration in the headspace of an operating sewer network. After a few month OPC materials started to deteriorate whereas CAC materials were still intact. The better durability of CAC materials is due to the presence of alumina providing a combination of protective mechanisms. On-site environmental parameters were monitored and analysed in the context of the biological and chemical mechanisms involved in material degradation. These data will eventually feed into the development of a representative, reproducible and accelerated laboratory test.

Rhabdomyosarcoma (RMS) is a paediatric soft-tissue sarcoma arising from skeletal muscle precursors coexpressing markers of proliferation and differentiation. Inducers of myogenic differentiation suppress RMS tumourigenic phenotype. The Notch target gene HES1 is upregulated in RMS and prevents tumour cell differentiation in a Notch-dependent manner. However, Notch receptors regulating this phenomenon are unknown. In agreement with data in RMS primary tumours, we show here that the Notch3 receptor is overexpressed in RMS cell lines versus normal myoblasts. Notch3-targeted downregulation in RMS cells induces hyper-phosphorylation of p38 and Akt essential for myogenesis, resulting in the differentiation of tumour cells into multinucleated myotubes expressing Myosin Heavy Chain. These phenomena are associated to a marked decrease in HES1 expression, an increase in p21(Cip1) level and the accumulation of RMS cells in the G1 phase. HES1-forced overexpression in RMS cells reverses, at least in part, the pro-differentiative effects of Notch3 downregulation. Notch3 depletion also reduces the tumourigenic potential of RMS cells both in vitro and in vivo. These results indicate that downregulation of Notch3 is sufficient to force RMS cells into completing a correct full myogenic program providing evidence that it contributes, partially through HES1 sustained expression, to their malignant phenotype. Moreover, they suggest Notch3 as a novel potential target in human RMS.

We developed a polymerase chain reaction (PCR)-based method for the identification of lactobacilli at the genus level. One specific primer, LbLMA1-rev, was designed by analysing similarities between the nucleotide sequence of the spacer between the 16S and 23S rRNA genes in a number of Lactobacillus strains. Amplification with LbLMA1-rev and R16-1, a universal primer, generated a PCR product for 23 Lactobacillus species. Electrophoresis did not reveal any discrete bands when Escherichia coli, Lactococcus lactis, Leuconostoc mesenteroides, Streptococcus thermophilus, Carnobacterium pissicola, Pediococcus pentosaceus, Bifidobacterium bifidum, Weissella confusa, Enterococcus hirae, Staphylococcus aureus or Listeria monocytogenes DNA were used as template.

Abstract In this study, the M13 primer was used to distinguish Geotrichum candidum from the anamorphic and teleomorphic forms of other arthrospore-forming species (discriminatory power = 0.99). For intraspecific characterization, the GATA4 primer showed the highest level of discrimination for G. candidum among the 20 microsatellite primers tested. A molecular typing protocol (DNA concentration, hybridization temperature and type of PCR machine) was optimized through a series of intra- and interlaboratory trials. This protocol was validated using 75 strains of G. candidum, one strain of G. capitatum and one strain of G. fragrans, and exhibited a discrimination score of 0.87. This method could therefore be used in the agro-food industries to identify and to evaluate biodiversity and trace strains of G. candidum. The results show that the GATA4 primer might be used to differentiate strains according to their ecological niche.

The space-time separated representation method (Ladevèze, C. R. Acad. Sci. Paris 309(II):1095–1099, 1989 ; Ammar et al., J. Non-Newton. Fluid Mech. 144:98–121, 2007 ) is here extended to solve strongly coupled multiphysics problems. The feasibility of the method for dealing with strongly coupled multiphysics problems with different characteristic times is here discussed and a new strategy to solve the nonlinear system for the basis enrichment is proposed. The method is validated in the case of a strongly coupled thermoviscoelastic model.

Mechanical effects can influence significantly electrical performance and life time of PEM fuel cells. A linear elasticplastic 2D model of fuel cell with hardening is used for modeling of assembly procedure of fuel cells. The model simulates mechanical behavior of the main components of real fuel cell (the membrane, the gas diffusion layers, the graphite plates, and the seal joints) and clamping elements (the steel plates, the bolts, the nuts). The stress and plastic deformation in MEA have been calculated using ABAQUS code. The results are presented on the local and the global scales with respect to the realistic clamping conditions. The first one corresponds to the single tooth/channel structure. The global scale deals with features of the entire cell and takes into account the border effects, in particular the influence of seal joints.