Théorie de l’esprit et communication chez les primates non-humains

La question de l’existence d’une théorie de l’esprit chez les primates non-humains a été posée il y a plus de 30 ans et depuis, le débat reste ouvert. La difficulté de trouver un consensus vient probablement du fait que la théorie de l’esprit n’est pas une capacité monolithique, mais implique différents types d’états mentaux. C’est à travers une revue de la littérature que nous évaluerons l’implication potentielle de ces différents états mentaux dans les échanges communicatifs des primates non-humains. Nous examinerons le principe d’intentionnalité dans divers contextes de communication. Nous analyserons ensuite le rôle de l’attention conjointe dans les gestes de pointages et leur lien direct avec la capacité d’attention partagée. Enfin, nous aborderons la manière dont certains grands singes parviennent à adapter leur comportement à l’ignorance qu’ils attribuent à autrui, sans pouvoir néanmoins leur attribuer de fausse croyance.The question of the existence of a theory of mind in non-human primates was raised over 30 years ago and today, the debate remains open. The difficulty of finding a consensus probably comes from the fact that theory of mind is not a monolithic ability but involves different kinds of mental states. Through a literature review we will assess the possible implication of these different mental states in communicative exchanges of nonhuman primates. We will consider the principle of intentionality in various communication contexts. We will then analyze the role of joint attention in pointing gesture and its direct link with the ability to shared attention. Finally, we will discuss how some primates are able to adapt their behavior to ignorance they attribute to others, however without being able to ascribe them false belief

Approche développementale de la théorie de l'esprit, de la conscience de soi et de leurs relations

Les cinq études détaillées au cours de cette thèse interrogent divers aspects de la théorie de l’esprit, de la conscience de soi ainsi que du lien (multiple ou unique) qui unit ces deux capacités sociocognitives si particulières. Les deux premières études mettent en évidence différentes variables qui peuvent – ou non- influencer l’attribution d’intention et de fausse croyance à autrui. La troisième étude porte plus précisément sur les différents composants de la conscience de soi et sur leur trajectoire développementale. La quatrième étude interroge le lien développemental entre la théorie de l’esprit et la conscience de soi, alors que la dernière étude questionne la présence de ce lien chez les chimpanzés (Pan Troglodytes). Nous démontrerons, tout au long de cette thèse, que la théorie de l’esprit et la conscience de soi sont composées de différents éléments et que leur acquisition est graduelle.Doctorat en Sciences Psychologiques et de l'éducationinfo:eu-repo/semantics/nonPublishe

Approche développementale de la théorie de l'esprit, de la conscience de soi et de leurs relations

Les cinq études détaillées au cours de cette thèse interrogent divers aspects de la théorie de l’esprit, de la conscience de soi ainsi que du lien (multiple ou unique) qui unit ces deux capacités sociocognitives si particulières. Les deux premières études mettent en évidence différentes variables qui peuvent – ou non- influencer l’attribution d’intention et de fausse croyance à autrui. La troisième étude porte plus précisément sur les différents composants de la conscience de soi et sur leur trajectoire développementale. La quatrième étude interroge le lien développemental entre la théorie de l’esprit et la conscience de soi, alors que la dernière étude questionne la présence de ce lien chez les chimpanzés (Pan Troglodytes). Nous démontrerons, tout au long de cette thèse, que la théorie de l’esprit et la conscience de soi sont composées de différents éléments et que leur acquisition est graduelle.Doctorat en Sciences Psychologiques et de l'éducationinfo:eu-repo/semantics/nonPublishe

The difference between deliberate and accidental consequences of actions in children and chimpanzees.

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The role of goal-directed behavior in intention attribution in children

In this study, we addressed the question of the nature of the information needed by 13-month-old infants to understand another agent's intentions. In two experiments, an experimenter was either unable or unwilling to give a toy to an infant. Importantly, an implement (a gutter in which the toy could roll down toward the infant) was used to make the experimenter's behavior as similar as possible in the two conditions. When the experimenter remained still in both conditions, infants did not behave differently according to the experimenter's intentions, suggesting that they did not infer them. By contrast, in a second experiment, where the experimenter performed an action directed toward the gutter in both conditions, the infants looked away from the experimental setting more often and longer in the unwilling condition than in the unable condition. They also looked more toward the experimenter in the unable condition than in the unwilling condition. Therefore, we conclude that an agent's intentional attitude can already be inferred by a 13-month-old provided that this intention is concretely shown through a goal-directed action. © 2012.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Characterization of the interaction partners of secreted proteins and chaperones of Shigella flexneri

International audienceThe type III secretion (TTS) system of Gram-negative pathogenic bacteria is composed of proteins that assemble into the TTS machinery, proteins that are secreted by this machinery and specific chaperones that are required for storage and sometimes secretion of these proteins. Many sequential protein interactions are involved in the TTS pathway to deliver effector proteins to host cells. We used the yeast two-hybrid system to investigate the interaction partners of the Shigella flexneri effectors and chaperones. Libraries of preys containing random fusions with fragments of the TTS proteins were screened using effectors and chaperones as baits. Interactions between the effectors IpaB and IpaC and their chaperone IpgC were detected by this method, and interaction domains were identified. Using a His-tagged IpgC protein to co-purify truncated IpaB and IpaC proteins, we showed that the chaperone-binding domain was unique and located in the N-terminus of these proteins. This domain was not required for the secretion of recombinant proteins but was involved in the stability of IpaC and instability of IpaB. Homotypic interactions were identified with the baits IpaA, IpaB and IpaC. Interactions between effectors and components of the TTS machinery were also selected that might give insights into regulation of the TTS process

Alteration of selenoprotein expression during stress and in aging

International audienceSelenium (Se) is an essential trace element implicated in many facets of human health and disease. Most of its beneficial effects are attributed to its presence as selenocysteine in a small, but vital group of proteins, namely the selenoproteins. They are implicated in antioxidant defense, redox homeostasis, redox signaling and possibly other cellular processes. The selenoproteome is primarily controlled by Se bioavailability that induces prioritization of protein biosynthesis, when this trace element is deficient. The hierarchical regulation of the selenoproteome by other exogenous stimuli, cellular stressors or pathophysiological conditions is poorly understood. Understanding biological causes of aging also remains challenging, although several theories and concepts have emerged in the past decades. Characterization of biomarkers of aging is controversial even with the impressive amount of ‘omic’ analyses performed in many living organisms. Accumulation of age-related damage, including oxidative-induced cellular damage, and the decreasing efficiency in elimination and repair systems have been extensively reported, being either a cause or consequence of the aging phenomenon. In this regard, and given the role of Se in redox biology of organisms, studying regulation of the selenoproteome in response to oxidative stress and aging is essential. This chapter reviews the current knowledge in this area

Interplay between Selenium Levels and Replicative Senescence in WI-38 Human Fibroblasts: A Proteomic Approach

Selenoproteins are essential components of antioxidant defense, redox homeostasis, and cell signaling in mammals, where selenium is found in the form of a rare amino acid, selenocysteine. Selenium, which is often limited both in food intake and cell culture media, is a strong regulator of selenoprotein expression and selenoenzyme activity. Aging is a slow, complex, and multifactorial process, resulting in a gradual and irreversible decline of various functions of the body. Several cellular aspects of organismal aging are recapitulated in the replicative senescence of cultured human diploid fibroblasts, such as embryonic lung fibroblast WI-38 cells. We previously reported that the long-term growth of young WI-38 cells with high (supplemented), moderate (control), or low (depleted) concentrations of selenium in the culture medium impacts their replicative lifespan, due to rapid changes in replicative senescence-associated markers and signaling pathways. In order to gain insight into the molecular link between selenium levels and replicative senescence, in the present work, we have applied a quantitative proteomic approach based on 2-Dimensional Differential in-Gel Electrophoresis (2D-DIGE) to the study of young and presenescent cells grown in selenium-supplemented, control, or depleted media. Applying a restrictive cut-off (spot intensity ±50% and a p value < 0.05) to the 2D-DIGE analyses revealed 81 differentially expressed protein spots, from which 123 proteins of interest were identified by mass spectrometry. We compared the changes in protein abundance for three different conditions: (i) spots varying between young and presenescent cells, (ii) spots varying in response to selenium concentration in young cells, and (iii) spots varying in response to selenium concentration in presenescent cells. Interestingly, a 72% overlap between the impact of senescence and selenium was observed in our proteomic results, demonstrating a strong interplay between selenium, selenoproteins, and replicative senescence