The Institute of Biology of École normale supérieure (IBENS) is a fundamental research centre in Life sciences. Our research aims at deciphering the fundamental mechanisms at the core of biological processes. IBENS (ENS, CNRS and Inserm joint unit) hosts over 300 people in 30 autonomous teams. The research environment is highly collaborative and interdisciplinary, and combines experimental and theoretical approaches. Our activities cover fields as various as functional genomics, neurobiology, developmental biology, ecology and evolution biology. Several technological platforms, notably in imaging, genomics, computational biology and proteomics, provide a robust support to the activities of the different teams. Our research also benefits from the high potential of interactions with other scientific departments in ENS (physics, chemistry, mathematics, informatics, etc.). ENS is deeply involved in the formation of students and young researchers at all levels. The host team -Inhibitory transmission and neuronal computation-- is headed by -Stéphane Dieudonné- Our research is -to understand how inhibitory transmission is used to perform basic neuronal computations and solve tasks devoted to the brain
Project: Multiphoton voltage recordings of inhibitory cerebellar circuits participating in pattern separation in vivo.
Cerebellar neural circuits need to treat and distinguish massively overlapping patterns of inputs, to make sense of sensory-motor information arising during body motion, environmental exploration and perception. This is obtained by so- called pattern separation, a key process implemented in several brain regions. In the cerebellum, the prevailing hypothesis states that the billions of granule cells in the granular layer of the cerebellar cortex perform a combinatorial expansion of the sensory-motor patterns. Separation is then obtained by simple thresholding of the most active granule cells, as operated by the only source of inhibition to granule cells: the network of Golgi Cells (GoC). However, theoretical considerations indicate that a simple homogeneous inhibition would be ill-suited to separate patterns optimally. We posit that the various synaptic circuits which we have recently shown to converge on Golgi cells are able to shape the activity of individual GoCs, within their electrically-coupled population network, to provide meaningful context-dependent inhibitory contrast on the granule cell population. We have recently performed the world-first optical recordings of membrane voltage from specifically defined cell types in awake behaving mice using custom made two-photon random-access microscopy. Using genetically encoded voltage indicators combined with ultrafast two photon recordings we can now investigate, at the microcircuit level, information transfer in the cerebellum. Specifically, we propose to examine whether, and through which rules and mechanisms, GoC inhibition may participate in pattern separation of granular layer input modalities. We will perform simultaneous presynaptic and postsynaptic optical recordings of activity in granule cells, GoCs and the various inputs controlling the later. By dissecting the input-output relationship of these circuits we should be able to answer whether and how GoCs are instrumental in optimizing the separation of cerebellar input patterns by granule cells. Our lab, located in the Institut de Biologie de l'Ecole Normale Supérieure, provides a rich and vibrant experimental and training environment, in addition to all the required facilities (animal breeding, virus production, imaging, FabLab), to embark on this project. The team is highly multidisciplinary, combining expertise ranging from state-of-the-art molecular biology to physiology, optics and instrumental development. The selected candidate will have full access to unique ultrafast random-access multiphoton microscopy, developed in the lab in the past decade.Web site for additional job details
https: // emploi.cnrs.fr/Offres/Doctorant/UMR8197-NATBOI-135/Default.aspxRequired Research Experiences
Neurosciences: Master Degree or equivalent
Biological sciences: Master Degree or equivalent
FRENCH: BasicContact Information