Accreditation to supervise researches: Exploring infant brain development using anatomical and functional imaging

To understand how babies can acquire amazing cognitive abilities and learn from their environment, it is essential to explore how the human brain develops in vivo using non-invasive neuroimaging techniques such as magnetic resonance imaging (MRI) and electro encephalography (EEG). Such studies are also necessary to understand various neuro developmental disorders and investigate the plasticity mechanisms that take place during early childhood. At the interface between neuro scientific and clinical questions, the research that I have been carrying out for around fifteen years aims to study how the brain of newborns and infants is early organized and becomes mature at the structural level in relation to its functional development. To do this, it is necessary to implement specific data acquisition, processing and analysis methodologies. During my doctorate (CEA, Service Hospitalier Frederic Joliot, Gif-sur-Yvette, 2002-2006), I was first interested in the development of white matter connections in infants, using an approach based on Diffusion tensor MRI (DTI) and tractography. This allowed us to show the early organization of the main fascicles, as well as their differential maturation relative to the functional networks they underlie. During my post-doctoral fellowships (University Hospitals of Geneva, Switzerland, then Inserm Childhood Epilepsies and Cerebral Plasticity Unit, Paris; 2006-2009), I mapped the folding of the cerebral cortex in premature newborns on the basis anatomical MRI images. We then characterized their progression during the last trimester of pregnancy, and highlighted early differences between newborns born from singleton, twin pregnancies, or presenting prenatal growth retardation. Since my recruitment as a research fellow at Inserm in 2009, I have carried out various studies in infants and children, within the Developmental Imaging team of the Cognitive Neuroimaging Unit (NeuroSpin center, CEA, Saclay), focusing more specifically on the development of brain networks relating to vision and language. We have thus detailed the microstructural maturation of cortical and white matter regions, taking advantage of the complementarity of different MRI parameters (T1, T2, DTI). Thanks to an original approach comparing MRI measurements and EEG potentials evoked by visual and auditory stimulation, we have linked structural maturation phenomena and certain functional properties of brain responses during the first post-natal months. Most of this work was carried out in interactions with 17 master's, doctoral and post-doctoral students whom I have had the opportunity to co-supervise for 8 years, and thanks to various funding (Fondation de France, Fondation Fyssen, ANR, etc.). Although the macroscopic measurements provided by neuroimaging only indirectly reflect the multiple developmental mechanisms that take place at the microscopic scale (such as the growth and pruning of dendritic arborizations, synaptogenesis, or even myelination), my research have made it possible to reveal certain early properties of cerebral architecture. In place from birth, the main anatomical-functional networks mature gradually and asynchronously. This development, both constrained and flexible, at the origin of plasticity processes, would allow the young child to acquire various capacities based on his perceptions and experiences, and to learn multiple skills in interactions with his environment. With a view to partially reorienting my research around clinical themes, in January 2019 I joined the NeuroDiderot Unit (Robert Debre Hospital, Paris) while maintaining close collaboration with the NeuroSpin scientific teams. Within the inDev team (Imaging of neuro developmental phenotypes), I am responsible for the axis dedicated to early development and its disturbances during pregnancy (e.g. prenatal growth retardation, exposure to alcohol) or in links with birth (e.g. prematurity, neonatal vascular accident). My main project focuses on the sensorimotor development of infants. It aims to characterize the specialization and progressive maturation of this brain network in relation to different parts of the body. In particular, premature newborns are exposed for several weeks to altered sensory perceptions and motor experiences compared to fetuses in utero, and we will explore to what extent their development may be impacted. We hope to provide early brain markers that can be used in clinical practice for the diagnosis and prognosis of infants at risk of developing later sensorimotor disorders. (author)