Biology subjects

Lecuyer, A.

Publications and source records attributed to Lecuyer, A..

6 recordsLinked to original sources

bioRxiv2025

A targeted amplicon sequencing panel for cost-effective high-throughput genotyping of Aedes aegypti

The mosquito Aedes aegypti is the primary vector for several medically significant arboviruses, including dengue, Zika, chikungunya, and yellow fever. Studying the genetic diversity of Ae. aegypti is crucial for understanding its evolutionary history, population dynamics, and the effectiveness of vector control methods. Due to the large genome size of Ae. aegypti, whole-genome sequencing (WGS) is often cost-prohibitive for large-scale studies. Recent advances in reduced-representation methods, aiming to reduce costs by sequencing only a small portion of the genome, provide cost-effective alternatives. However, a standardized set of genome-wide markers specifically designed for population genetic studies of Ae. aegypti remains unavailable. Here, we present a targeted amplicon sequencing panel designed for cost-effective, high-throughput genotyping across 291 loci distributed throughout the Ae. aegypti genome. Our in silico analyses indicate that this amplicon panel effectively replicates population structure analyses typically derived from WGS data. We demonstrate that the amplicon panel accurately discriminates between diverse laboratory colonies of Ae. aegypti and consistently measures individual genetic admixture to a degree comparable with WGS. By enabling high-throughput genotyping at a reduced cost, we anticipate that our targeted amplicon sequencing panel will facilitate large-scale genotyping studies of Ae. aegypti for vector surveillance and population structure analyses, especially in resource-limited settings.

genomics↗

bioRxiv2025

Polygenic viral factors enable efficient mosquito-borne transmission of African Zika virus

Zika virus (ZIKV) is a mosquito-borne flavivirus primarily transmitted among humans by Aedes aegypti. Over the past two decades, it has caused significant outbreaks associated with birth defects and neurological disorders. Phylogenetically, ZIKV consists of two main genotypes referred to as the African and Asian lineages, each exhibiting distinct biological properties. African lineage strains are transmitted more efficiently by mosquitoes, but pinpointing the genetic basis of this difference has remained challenging. Here, we address this question by comparing recent African and Asian strains using chimeric viruses, in which segments of the parental genomes are swapped. Our results show that the structural genes from the African strain enhance viral internalization, while the non-structural genes improve genome replication and infectious particle production in mosquito cells. In vivo mosquito transmission is most significantly influenced by the structural genes, although no single viral gene alone determines this effect. Additionally, we develop a stochastic model of in vivo viral dynamics in mosquitoes that mirrors the observed patterns, suggesting that the primary difference between the African and Asian strains lies in their ability to traverse the mosquito salivary glands. Overall, our findings suggest that the polygenic nature of ZIKV transmissibility has prevented Asian lineage strains from achieving the same epidemic potential as African lineage strains, underscoring the importance of lineage-specific adaptive landscapes in shaping ZIKV evolution and emergence.

microbiology↗

bioRxiv2024

Introducing Haptic Feedback in Real-Time fMRI Neurofeedback: A Novel Approach to Modulate Primary Motor Cortex Activity

As fMRI-Neurofeedback (fMRI-NF) is still in its early stages, many questions remain regarding the optimal methodology, particularly in relation to feedback modalities. One of the core components of neurofeedback is the feedback itself, which the participant relies on to regulate, learn, and refine their mental strategies. However, most fMRI-NF protocols to date have primarily used visual feedback, which may not be ideal in all cases. Certain individuals or populations might benefit from alternative or additional feedback modalities, such as haptic feedback --a novel approach in this field-- along with auditory, virtual reality/immersive environments, or a combination of these. In this study, we assess the performance of neurofeedback elicited by a motor imagery (MI) task using visuo-haptic feedback and compare it to unisensory visual and haptic feedback. Our results suggest that combining visual and haptic feedback in neurofeedback may be more engaging than conventional visual feedback alone, particularly in neurorehabilitation, by more effectively activating the primary motor cortex--a region considered a key target for promoting motor recovery.

bioengineering↗

bioRxiv2023

Extensive variation and strain-specificity in dengue virus susceptibility among African Aedes aegypti populations

African populations of the mosquito Aedes aegypti are usually considered less susceptible to infection by human-pathogenic flaviviruses than globally invasive populations found outside Africa. Although this contrast has been well documented for Zika virus (ZIKV), it is unclear to what extent it is true for dengue virus (DENV), the most prevalent flavivirus of humans. Addressing this question is complicated by substantial genetic diversity among DENV strains, most notably in the form of four genetic types (DENV1 to DENV4), that can lead to genetically specific interactions with mosquito populations. Here, we carried out a continent-wide survey of DENV susceptibility using a panel of field-derived Ae. aegypti colonies from across the African range of the species and a colony from Guadeloupe, French West Indies as non-African reference. We found considerable variation in the ability of African Ae. aegypti populations to acquire and replicate a panel of six DENV strains spanning the four DENV types. Although African Ae. aegypti populations were generally less susceptible than the reference non-African population from Guadeloupe, in several instances some African populations were equally or more susceptible than the Guadeloupe population. Moreover, the relative level of susceptibility between African mosquito populations depended on the DENV strain, indicating genetically specific interactions. We conclude that unlike ZIKV susceptibility, there is no clear-cut dichotomy in DENV susceptibility between African and non-African Ae. aegypti. DENV susceptibility of African Ae. aegypti populations is highly heterogeneous and largely governed by the specific pairing of mosquito population and DENV strain. Author summaryAfrican populations of the mosquito Aedes aegypti are usually thought to be less likely to get infected by flaviviruses compared to Ae. aegypti mosquitoes found outside Africa. While this has been well-demonstrated for Zika virus, it is not clear if the same is true for dengue virus, which is the most common flavivirus in humans. Studying this is complicated by the strain diversity of dengue virus, including four main genetic types, potentially causing different interactions. In this study, we compared several mosquito populations and found that, in general, African mosquitoes were less likely to get infected by dengue virus compared to mosquitoes from outside Africa. However, in some cases, African mosquitoes were just as or even more likely to get infected. The specific strain of dengue virus also influenced how likely African mosquitoes were to get infected, showing that the relationship between African mosquitoes and dengue virus is complex.

microbiology↗

bioRxiv2019

Simultaneous MRI-EEG during a motor imagery neurofeedback task: an open access brain imaging dataset for multi-modal data integration.

Combining EEG and fMRI allows for integration of fine spatial and accurate temporal resolution yet presents numerous challenges, noticeably if performed in real-time to implement a Neurofeedback (NF) loop. Here we describe a multimodal dataset of EEG and fMRI acquired simultaneously during a motor imagery NF task, supplemented with MRI structural data. The study involved 30 healthy volunteers undergoing five training sessions. We showed the potential and merit of simultaneous EEG-fMRI NF in previous work. Here we illustrate the type of information that can be extracted from this dataset and show its potential use. Our group is the second in the world to have integrated EEG and fMRI for NF, therefore this dataset is unique of its kind. We believe that it will be a valuable tool to O_LIAdvance and test methodologies to integrate complementary neuroimaging techniques (design and validation of methods of multi-modal data integration at various scales) C_LIO_LIImprove the quality of Neurofeedback provided C_LIO_LIImprove methodologies for de-noising EEG acquired under MRI C_LIO_LIInvestigate the neuromarkers of motor-imagery using multi-modal information C_LI

neuroscience↗

bioRxiv2018

Learning 2-in-1: towards integrated EEG-fMRI-neurofeedback

Neurofeedback (NF) allows to exert self-regulation over specific aspects of ones own brain activity by returning information extracted in real-time from brain activity measures. These measures are usually acquired from a single modality, most commonly electroencephalography (EEG) or functional magnetic resonance imaging (fMRI). EEG-fMRI-neurofeedback (EEG-fMRI-NF) is a new approach that consists in providing a NF based simultaneously on EEG and fMRI signals. By exploiting the complementarity of these two modalities, EEG-fMRI-NF opens a new spectrum of possibilities for defining bimodal NF targets that could be more robust, flexible and effective than unimodal ones. Since EEG-fMRI-NF allows for a richer amount of information to be fed back, the question arises of how to represent the EEG and fMRI features simultaneously in order to allow the subject to achieve better self-regulation. In this work, we propose to represent EEG and fMRI features in a single bimodal feedback (integrated feedback). We introduce two integrated feedback strategies for EEG-fMRI-NF and compare their early effects on a motor imagery task with a between-group design. The BiDim group (n=10) was shown a two-dimensional (2D) feedback in which each dimension depicted the information from one modality. The UniDim group (n=10) was shown a one-dimensional (1D) feedback that integrated both types of information even further by merging them into one. Online fMRI activations were significantly higher in the UniDim group than in the BiDim group, which suggests that the 1D feedback is easier to control than the 2D feedback. However subjects from the BiDim group produced more specific BOLD activations with a notably stronger activation in the right superior parietal lobe (BiDim > UniDim, p < 0.001, uncorrected). These results suggest that the 2D feedback encourages subjects to explore their strategies to recruit more specific brain patterns. To summarize, our study shows that 1D and 2D integrated feedbacks are effective but also appear to be complementary and could therefore be used in a bimodal NF training program. Altogether, our study paves the way to novel integrated feedback strategies for the development of flexible and effective bimodal NF paradigms that fully exploits bimodal information and are adapted to clinical applications.

bioengineering↗