Biology subjects

Granjon, L.

Publications and source records attributed to Granjon, L..

4 recordsLinked to original sources

bioRxiv2025

Role of the locus coeruleus noradrenergic system in susceptibility and resilience following early life stress in male and female mice

Child adversity (CA), encompassing emotional, physical, and sexual maltreatment or abuse, affects a substantial number of children worldwide. Moreover, it is the leading predictor of psychiatric disorders such as major depressive disorder (MDD), anxiety, and suicidal behavior. Despite the robust link between CA and psychopathology, individual outcomes vary significantly, with some children demonstrating resilience. Resilience is an adaptive and dynamic process, which mitigates the long-term effects of CA, suggesting potential protective mechanisms that remain underexplored. This study investigates behavioural susceptibility and resilience following early life stress (ELS) and examined whether these outcomes are associated with sex-dependent alteration of the locus coeruleus-norepinephrine (LC-NE) system, a critical modulator of stress, cognition, and emotion. Using a maternal deprivation model combined with limited nesting and bedding, we examined sex-dependent behavioral, physiological, and neurobiological markers associated with ELS outcomes in mice. Behavioral clustering revealed distinct phenotypes: resilient, anxious, and anhedonic-like with sex-specific differences in distribution. Early markers, including body weight and ultrasonic vocalization (USV) patterns, were linked to long-term susceptibility. Neuroanatomical analyses identified sex-specific LC-NE activation patterns associated with resilient and susceptible phenotype, particularly within the caudal-dorsal LC. These findings highlight sex-dependent behavioural trajectories of ELS that are associated with distinct LC-NE activation patterns, offering insights into potential interventions targeting resilience mechanisms in children exposed to CA.

neuroscience↗

bioRxiv2019

Impact of historical and current features of the cityscape on the genetic structure of the house mouse (Mus musculus domesticus) in Dakar (Senegal, West Africa)

AO_SCPLOWBSTRACTC_SCPLOWPopulation genetic approaches may be used to investigate dispersal patterns of species living in highly urbanized environment in order to improve management strategies for biodiversity conservation or pest control. However, in such environment, population genetic structure may reflect both current features of the cityscape and urbanization history. This can be especially relevant when focusing on exotic commensal rodents that have been introduced in numerous primary colonial European settlements. Accounting for spatial and temporal cityscape heterogeneity to determine how past and recent demographic events may interplay to shape current population genetic structure of synanthropic rodents may provide useful insights to manage their populations. In this study, we addressed these issues by focusing on the house mouse, Mus musculus domesticus, in Dakar, Senegal, where the species may have been introduced as soon as Europeans settled in the middle of the nineteenth century. We examined genetic variation at one mitochondrial locus and 15 nuclear microsatellite markers from individuals sampled in 14 sampling sites representing different stages of urbanization history and different socio-economic environments in Dakar. We used various approaches, including model-based genetic clustering and model-free smoothing of pairwise genetic estimates. We further linked observed spatial genetic patterns to historical and current features of Dakar cityscape using random forest and Bayesian conditional autoregressive models. Results are consistent with an introduction of the house mouse at colonial time and the current genetic structure exhibits a gradient-like pattern reflecting the historical process of spatially continuous expansion of the city from the first European settlement. The genetic patterns further suggest that population dynamics of the house mouse is also driven by the spatial heterogeneity of the current cityscape, including socio-economics features, that translate in habitat quality. Our results highlight the potential importance of accounting for past demographic events to understand spatial genetic patterns of nonnative invasive commensal rodents in highly urbanized environment.

ecology↗

bioRxiv2017

AWARENESS OF THE OUTCOME OF SELF-INITIATED POINTING ACTIONS

Are we aware of the outcome of our actions? The participants pointed rapidly at a screen location marked by a transient visual target (T), with and without seeing their hand, and were asked to estimate (E) their landing location (L) using the same finger but without time constraints. We found that L and E are systematically and idiosyncratically shifted away from their corresponding targets (T, L), suggesting unawareness. Moreover, E was biased away from L, toward T (21% and 37%, with and without visual feedback), in line with a putative Bayesian account of the results, assuming a strong prior in the absence of vision. However, L (the assumed prior) and E (the assumed posterior) precisions were practically identical, arguing against such an account of the results. Instead, the results are well accounted for by a simple model positing that the participants E is set to the planned rather than the actual L. When asked to estimate their landing location, participants appeared to reenact their original motor plan.

animal behavior and cognition↗

bioRxiv2017

Fossils know it best: using a new set of fossil calibrations to improve the temporal phylogenetic framework of murid rodents (Rodentia: Myomorpha: Muroidea: Muridae)

Murid rodents (Rodentia: Myomorpha: Muroidea: Muridae) represent the most diverse and abundant mammalian group. In this study, we reconstruct a dated phylogeny of the family using a multilocus dataset (six nuclear and nine mitochondrial gene fragments) encompassing 160 species representing 82 distinct murid genera from four extant subfamilies (Deomyinae, Gerbillinae, Lophiomyinae, and Murinae). In comparison with previous studies on murid or muroid rodents, our work stands out for the implementation of multiple fossil constraints within the Muridae thanks to a thorough review of the fossil record. Before being assigned to specific nodes of the phylogeny, all potential fossil constraints were carefully assessed; they were also subjected to several cross-validation analyses. The resulting phylogeny is consistent with previous phylogenetic studies on murids, and recovers the monophyly of all sampled murid subfamilies and tribes. Based on nine controlled fossil calibrations, our inferred temporal timeframe indicates that the murid family likely originated in the course of the Early Miocene, 23.0-16.0 million years ago (Ma), and that most major lineages (i.e. tribes) have started diversifying ca. 10 Ma. Historical biogeography analyses support the Paleotropical origin for the family, with an initial internal split (vicariance event) followed by subsequent migrations between Afrotropical and Indomalayan lineages. During the course of their diversification, the biogeographic pattern of murids is marked by several dispersal events toward the Australasian and the Palearctic regions, mostly from the Indomalaya. The Afrotropical region was also secondarily colonized at least three times from the Indomalaya, indicating that the latter region has acted as a major centre of diversification for the family.

zoology↗