Comparative analysis of canine and human melanomas

This paper presents epidemiological and clinical data from 2350 cases of melanocytic tumours from dogs sampled in France. In addition, we present the histological and genetic characterization of subsets of melanoma cases (n=153 and n=100, respectively), with a comparative aspect to human melanomas. Dog melanomas occur at the same anatomical sites than human melanomas, but with different frequency and severity. We demonstrate that the specificities of dog melanomas make them good models to understand the non-UV pathways of human melanomas. Interestingly, somatic mutations in oral canine melanomas were detected in the NRAS and PTEN genes, precisely at the same hotspots as human mutations. In contrast, mutations in the BRAF gene were not detected. This paper highlights the similarities and differences of dog and human melanoma types and the strong potential of dog melanomas to decipher the non-UV light pathways in different melanoma types, especially mucosal and acral types.Cet article présente les données épidémiologiques et cliniques de 2350 cas de tumeurs mélanocytaires canines collectées en France. Nous avons réalisé la caractérisation histologique (n = 153) et génétique (n = 100) d'un sous-groupe de mélanomes dont les résultats ont été comparés aux données des mélanomes humains. Les mélanomes apparaissent aux mêmes sites anatomiques chez le chien et l'Homme, mais avec des fréquences et des sévérités différentes. Nous montrons les prédispositions raciales des mélanomes canins et l'intérêt de ce modèle pour rechercher les gènes prédisposant difficiles à identifier chez l'Homme. Des mutations somatiques dans les gènes NRAS et PTEN ont été détectées dans les mélanomes buccaux canins, précisément aux mêmes points chauds (hotspots) que les mutations de ces gènes chez l'homme. Au contraire, aucune mutation dans le gène BRAF n'a été retrouvée dans les échantillons canins analysés. Ce travail met en lumière les homologies et différences entre les types de mélanomes humains et canins et démontre la force du modèle canin pour analyser les voies de signalisation non UV-dépendantes des mélanomes humains, particulièrement dans les types muqueux et acraux

Exploration du réseau cérébral impliqué dans les traitements syntaxiques et lexico-sémantiques des phrases

Ce travail de thèse a pour but d explorer les aires cérébrales impliquées dans les traitements syntaxiques et sémantiques des phrases en IRMf chez des adultes sains. Nous avons observé des effets d adaptation lexico-sémantique dans la plupart des aires temporales et frontales impliquées dans le traitement des phrases. Nous avons trouvé plusieurs régions montrant des effets d adaptation à la répétition de la forme des mots, du sens des mots et de la structure argumentale de la phrase. Mais aucun effet clair d adaptation syntaxique n a pu être observé. Enfin, l implication des régions temporales supérieures antérieures et postérieures gauches, des régions frontales inférieures gauches et du putamen gauche dans la construction des constituants d une phrase a été montrée. Ces résultats suggèrent qu aucune aire cérébrale n est impliquée dans la représentation de l arbre syntaxique complet, alors que des aires sont impliquées dans la construction des constituants de la phrasePARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Spatial transfer of adaptation of scanning voluntary saccades in humans

International audienceThe properties and neural substrates of the adaptive mechanisms that maintain over time the accuracy of voluntary, internally triggered saccades are still poorly understood. Here, we used transfer tests to evaluate the spatial properties of adaptation of scanning voluntary saccades. We found that an adaptive reduction of the size of a horizontal rightward 71 saccade transferred to other saccades of a wide range of amplitudes and directions.This transfer decreased as tested saccades increasingly di¡ered in amplitude or direction from the trained saccade, being null for vertical and left-ward saccades. Voluntary saccade adaptation thus presents bounded, but large adaptation ¢elds, suggesting that at least part of the underlying neural substrate encodes saccades as vectors

Sentence Syntax and Content in the Human Temporal Lobe: An fMRI Adaptation Study in Auditory and Visual Modalities

& Priming effects have been well documented in behavioral psycholinguistics experiments: The processing of a word or a sentence is typically facilitated when it shares lexico-semantic or syntactic features with a previously encountered stimulus. Here, we used fMRI priming to investigate which brain areas show adaptation to the repetition of a sentence’s content or syntax. Participants read or listened to sentences organized in series which could or not share similar syntactic constructions and/or lexico-semantic content. The repetition of lexicosemantic content yielded adaptation in most of the temporal and frontal sentence processing network, both in the visual and the auditory modalities, even when the same lexicosemantic content was expressed using variable syntactic constructions. No fMRI adaptation effect was observed when the same syntactic construction was repeated. Yet behavioral priming was observed at both syntactic and semantic levels in a separate experiment where participants detected sentence endings. We discuss a number of possible explanations for the absence of syntactic priming in the fMRI experiments, including the possibility that the conglomerate of syntactic properties defining ‘‘a construction’ ’ is not an actual object assembled during parsing. &amp

Comparative proteomics to reveal naturally occurring variability in Arabidopsis thaliana accessions.

International audienc

Comparative proteomics to reveal naturally occurring variability in Arabidopsis thaliana accessions.

International audienc

Proteomic investigation of natural variation between Arabidopsis ecotypes

International audienc

Sex Differences in the Neural Correlates of Specific and General Autobiographical Memory

International audienceAutobiographical memory (AM) underlies the formation and temporal continuity over time of personal identity. The few studies on sex-related differences in AM suggest that men and women adopt different cognitive or emotional strategies when retrieving AMs. However, none of the previous works has taken into account the distinction between episodic autobiographical memory (EAM), consisting in the retrieval of specific events by means of mental time travel, and semantic autobiographical memory (SAM), which stores general personal events. Thus, it remains unclear whether differences in these strategies depend on the nature of the memory content to be retrieved. In the present study we employed functional MRI to examine brain activity underlying potential sex differences in EAM and SAM retrieval focusing on the differences in strategies related to the emotional aspects of memories while controlling for basic cognitive strategies. On the behavioral level, there was no significant sex difference in memory performances or subjective feature ratings of either type of AM. Activations common to men and women during AM retrieval were observed in a typical bilateral network comprising medial and lateral temporal regions, precuneus, occipital cortex as well as prefrontal cortex. Contrast analyses revealed that there was no difference between men and women in the EAM condition. In the SAM condition, women showed an increased activity, compared to men, in the dorsal anterior cingulate cortex, inferior parietal and precentral gyrus. Overall, these findings suggest that differential neural activations reflect sex-specific strategies related to emotional aspects of AMs, particularly regarding SAM. We propose that this pattern of activation during SAM retrieval reflects the cognitive cost linked to emotion regulation strategies recruited by women compared to men. These sex-related differences have interesting implications for understanding psychiatric disorders with differential sex prevalence and in which one of key features is overgenerality in AM

Don’t be Too Strict with Yourself! Rigid Negative Self-Representation in Healthy Subjects Mimics the Neurocognitive Profile of Depression for Autobiographical Memory

International audienceAutobiographical memory (AM) comprises representation of both specific (episodic) and generic (semantic) personal information. Depression is characterized by a shift from episodic to semantic AM retrieval. According to theoretical models, this process (“overgeneralization”), would be linked to reduced executive resources. Moreover, “overgeneral” memories, accompanied by a negativity bias in depression, lead to a pervasive negative self-representation. As executive functions and AM specificity are also closely intricate among “non-clinical” populations, “overgeneral” memories could result in depressive emotional responses. Consequently, our hypothesis was that the neurocognitive profile of healthy subjects showing a rigid negative self-image would mimic that of patients. Executive functions and self-image were measured and brain activity was recorded, by means of fMRI, during episodic AMs retrieval in young healthy subjects. The results show an inverse correlation, that is, a more rigid and negative self-image produces lower performances in both executive and specific memories. Moreover, higher negative self-image is associated with decreased activity in the left ventro-lateral prefrontal and in the anterior cingulate cortex, repeatedly shown to exhibit altered functioning in depression. Activity in these regions, on the contrary, positively correlates with executive and memory performances, in line with their role in executive functions and AM retrieval. These findings suggest that rigid negative self-image could represent a marker or a vulnerability trait of depression by being linked to reduced executive function efficiency and episodic AM decline. These results are encouraging for psychotherapeutic approaches aimed at cognitive flexibility in depression and other psychiatric disorders