The aim of this research program is to produce novel all-optical technologies to explore brain functions at the mesoscopic scale with cellular resolution opening a new phase in optogenetics that I named circuit optogenetics. Revealing the neural codes supporting specific mammalian brain functions is a daunting task demanding to relate in vivo the individual activities of large numbers of neurons recorded jointly within collectives that form distinct nodes of a network and to perform precisely targeted and calibrated interventions in the spatiotemporal dynamics of neural circuits on the scale of naturalistic patterns of activity. Despite recent technical advances, these experiments remain out of reach because we lack a comprehensive approach for large-scale, multi-region, in depth, single cell and millisecond precise manipulation of neural circuits. HOLOVIS will tackle these limitations through the construction of an innovative paradigm combining optogenetics with cutting-edge technology of wave front shaping, compressed sensing, microendoscopy, wave-guide probes, laser developments and opsin engineering. My lab has pioneered the use of wave front shaping for neuroscience and developed in the past years a number of new optical methods, for patterned optogenetic neuronal stimulation. Here, we will push forward this technology and first demonstrate the performances of these breakthrough systems to reveal how inter, intra-laminar and cortical/sub-cortical wiring construct and refine visual orientation selectivity in mice. We will focus on the visual system of mice, whose input-output responses to controlled sensory stimulations have been characterized in decades of studies. However, we are persuaded that our approach can be used to reveal the connectivity rules that underlie specific patterns of activity of any neuronal circuit, thus defining the functional building blocks of distinct brain areas.

Current scenarios predict an accelerated biodiversity erosion with climate change. However, uncertainties in predictions remain large because the multitude of climate change effects from genes to ecosystems and their interdependencies are still overlooked. This incomplete vision hampers the development of effective mitigation strategies to sustain biodiversity. Climate change can directly modify the phenotype and performance of individuals through phenotypic plasticity and evolution on contemporary time scales. The microevolution of keystone species can spread throughout the whole ecological network due to changes in species interactions and further translate into an altered ecosystem functioning. Conversely, direct impacts on communities and ecosystems can have ripple effects on the phenotypic distribution and evolution of all species of ecological networks. Climate-driven changes at individual and population levels can shape community composition and ecosystem functioning, and vice versa, altering eco-evolutionary feedbacks, namely the reciprocal interactions between ecological and evolutionary processes. Climate-driven ecological and evolutionary dynamics are yet often investigated separately. The role of eco-evolutionary feedbacks in climate change impacts on biological systems therefore hinges on little concrete empirical evidence contrasting with a profuse theoretical development. ECOFEED will investigate climate-dependent eco-evolutionary feedbacks using a 6 year-long realistic warming experiment reproducing natural conditions and thus allowing for both evolutionary and ecological dynamics to occur under a predicted climate change scenario. Complementary laboratory experiments will quantify reciprocal impacts of climate-dependent evolutionary and ecological changes on each other. ECOFEED will provide unprecedented insights on the eco-evolutionary feedbacks in a future climate and will ultimately help refine predictions on the future of biodiversity.

The unprecedented amount of photometric, spectroscopic, and astrometric data for billion stars provided by ongoing and future surveys and instruments (Gaia, APOGEE, WEAVE, MOONS, 4MOST, LSST, ELT, JWST) are allowing and will allow the detailed exploration of the Galactic history. These data will include kinematic and chemical information for stellar populations in all Galactic structures, such as the Galactic centre, globular clusters (GCs), their streams and escapees. Therefore, it is extremely timely to build a large library of models to exploit the data using star clusters as fossil records of past satellite accretion events. This motivates my work at GEPI, where I will link the large-scale dynamical evolution of Milky Way-like disc galaxies to that of their pc-scale elementary bricks as globular and nuclear star clusters (NSCs). By means of detailed N-body simulations, I will model the merger history of the Galaxy and follow the evolution of the GC system formed in the Milky Way and accreted from satellite galaxies. I will also make significant steps in advancing the understanding of NSCs, their formation and evolution and their link to the evolution of GCs and bulge/disc stellar populations. This project will greatly benefit from the knowledge and research done in the "Equipe Physique Stellaire et Galactique” of the GEPI laboratory at the Paris Observatory. This group has leading experts in the field of Galactic dynamics and stellar populations, chemical abundances of individual GCs, and is also strongly involved in the Gaia mission, and follow-up surveys (WEAVE, MOONS). Therefore, this environment is ideally suited for me to conduct my research. At the same time, I will bring in my expertise on the dynamical evolution of dense stellar systems, along with my international collaborations. The training provided at GEPI and Paris Observatory will be crucial to strengthen my skills and my professional profile, opening significant career development opportunities.

Mirror symmetry is one of the most mysterious dualities in mathematics. Roughly, it predicts that given any Calabi-Yau variety, there exists a mirror Calabi-Yau variety such that a rich list of geometric relations hold between the two, involving Hodge numbers, Gromov-Witten invariants, variation of Hodge structures, Floer homology (Fukaya category), coherent sheaves, stability conditions and so on. Despite continual progress in the subject, a fundamental question remains unclear: to what extent do mirrors exist, and how to construct the mirror variety? Here we propose a new approach to answer this question, based on latest developments from non-archimedean geometry, in particular the theory of Berkovich spaces, as well as derived non-archimedean geometry. Our goal is to conceive and pursue a full-fledged theory of non-archimedean mirror symmetry, which will lead to new results unattainable from existing methods. We propose to work out a general mirror construction, starting directly from a non-archimedean Strominger-Yau-Zaslow torus fibration, conjectured by Kontsevich-Soibelman, by counting non-archimedean analytic disks with boundaries on SYZ torus fibers. First we need to establish the existence of such counts in full generality, based on non-archimedean Gromov-Witten theory and tail conditions. Then we have to prove various properties of the mirror algebra, including associativity, radius of convergence and singularity estimates. Finally we propose to use wall-crossing formulas to glue local mirror algebras together to obtain the global mirror variety. A long-term goal is to show that the mirror construction is an involution, the best exhibition of mirror duality. We also aim for applications outside mirror symmetry, in particular towards the moduli of KSBA stable pairs in birational geometry. Our project is intimately related to the ongoing Gross-Siebert program based on logarithmic geometry. We also expect fruitful future interactions with their program.

The cerebellum is a key structure of the central nervous system that contains more than half the neurons of the brain. It is highly conserved across vertebrates and crucial for coordinated movement, motor learning and cognition. Cerebellar dysfunction causes a wide range of motor (ataxia, dystonia) or non-motor (autism, schizophrenia) disorders. It is made of two structures: the cerebellar cortex and the Deep Cerebellar Nuclei (DCN). While the former has been thoroughly studied, the DCN - the actual output of the structure - are much less understood. Technological limitations and experimental difficulties have limited the study of DCN processing rules both at the cellular and at the population level. A multidisciplinary approach combining recent discoveries on DCN structure, modern cell type labelling strategies and optogenetics, and novel optical tools based on work performed during my first postdoctoral project (acousto-optic 2-photon imaging coupled with GRIN lenses) will address the following fundamental open questions that limit our understanding of sensorimotor systems: 1) How are inputs carrying sensorimotor information from different parts of the brain (mossy fibres (MFs) and climbing fibres (CFs)) integrated by individual DCN neurons? 2) How are CFs and MFs carrying different sensory modalities processed by DCN neurons at the neuronal and dendritic levels? And how does it relate to distinct DCN neuron subpopulations? 3) What is the dynamic of these subpopulations during a behavioural task in vivo? The outcome of the DeepPop project will provide new knowledge of the computations performed in the cerebellum, novel optical solutions to study deep brain structures and data that will be used by the wider community (e.g. modellers, theoretician, clinicians) and increase our general understanding of sensorimotor systems.