We invite applications for postdoctoral researchers to join our team Neuronal Circuits & Brain Dynamics at the Paris Brain Institute (ICM) to study the principles of neuronal circuit organization and brain dynamics. If you are an ambitious and driven researcher, interested in experimental or computational systems and circuits neuroscience, and seeking an environment that fosters intellectual and professional growth, we invite you to consider joining our team. Together, we'll make a lasting impact on science and pave the way for your successful research career. Our team values diversity and welcomes researchers from all backgrounds and profiles. If your project ideas align with our research focus, we encourage you to get in touch with us. Research Topics We are interested in how neuronal circuits are organized and how the collective action of neurons gives rise to the emergent complex brain dynamics and behavior. We focus on how neurochemicals and bodily signals influence the brain. * We study how the simultaneous release of neuromodulators influences the activity of neurons and the coordination of brain regions * We also study how bodily signals, such as breathing, serve as fundamental elements of the oscillatory circuit architecture * We employ our approach to study the brain dynamics during behavior and sleep and their involvement in the transformation of fleeting experiences into long-term memories To answer these fundamental questions about the nature and function of the brain, we combine a range of cutting-edge neurotechnologies that enable us to observe and control the activity of the brain. We aim to identify and explore the fundamental principles of neural circuit organization and apply our understanding for the improvement of the human condition. Pure experimental, as well as computational/theoretical, or hybrid projects are available, depending on your interest and skills. Opportunities As a postdoctoral researcher in our group: • You will be an integral part of shaping our research direction and team culture. You will engage in exciting and meaningful research and will have access to all the tools necessary to push the boundaries of scientific exploration, with our cutting-edge techniques and state-of-the-art facilities. • You will have the opportunity to mentor graduate and master's students. This role enhances your leadership and communication skills while you contribute to the growth of the next generation of scientists. By guiding and collaborating with these aspiring researchers, you contribute to the collective knowledge and expertise of the team. Mentoring fosters a supportive and enriching atmosphere that reduces the mental strain of working alone on a project, as you can share ideas, problem-solve together, and gain fresh perspectives. • You will have ample opportunities to develop vital skills for your future academic career, such as mentoring, grant writing, presenting your work, publishing papers, and leading projects to completion. In parallel, you will gain invaluable first-hand experience in setting up and managing a young research team. • We encourage participation in conferences and workshops, where you can present your research findings to the wider scientific community. Why join our team • We are a young and vibrant group of scientists, fueled by curiosity and passion for understanding the brain. We work as a team and use or invent cutting-edge neurotechnologies to answer fundamental questions in neuroscience. • Our team is committed to the training, mentorship, and career development of the next generation of neuroscientists. To achieve that, we foster an inclusive and supportive environment, where we can learn and advance science while having fun in the process. • Our work is multi-disciplinary, and so is our team. Irrespective of your background and project, our research environment will expose you to a diverse range of experimental and computational aspects of systems and circuits neuroscience. We thus encourage everyone to apply, especially those from underrepresented minorities. • Working in our team will provide you with invaluable experience across all stages of research and you will have the opportunity to engage in experiment design and execution, method development, software design, and data analysis, as well as publishing and communicating research results. • Our team is affiliated with Inserm and is located in the Paris Brain Institute (ICM), where we have access to state-of-the-art facilities and resources. • Our vibrant community at the ICM and throughout Paris promotes broad collaboration and learning opportunities.

In most animals including in humans, emotions occur together with changes in the body, such as variations in breathing or heart rate, sweaty palms, or facial expressions. It has been suggested that this interoceptive information acts as a feedback signal to the brain, enabling adaptive modulation of emotions that is essential for survival. As such, fear, one of our basic emotions, must be kept in a functional balance to minimize risk-taking while allowing for the pursuit of essential needs. However, the neural mechanisms underlying this adaptive modulation of fear remain poorly understood. In this talk, I want to present and discuss the data from my PhD work where we uncover a crucial role for the interoceptive insular cortex in detecting changes in heart rate to maintain an equilibrium between the extinction and maintenance of fear memories in mice.

The main transmission mode of the COVID-19 disease is through virus-laden aerosols and droplets generated by expiratory events, such as breathing and sneezing. Patients with respiratory diseases are typically treated with oxygenation devices in hospitals, homes, and other settings where they increase the risk of spreading the disease to caregivers and first responders. Here, I will discuss a systematic study of aerosol and droplet dispersal through the air and their final deposition on surfaces. Through laser and fluorescent imaging techniques, we measure the volumetric spatial-temporal dynamics of droplet dispersal while varying rheological properties of the mucosaliva. We then demonstrate that a standard nose and mouth mask reduces the amount of mucosaliva dispersed by a factor of at least a hundred. Our ongoing collaborations with doctors and respiratory therapists from the Baystate Medical Hospital are developing new guidelines to help mitigate disease spread in a hospital setting.

In this presentation, we will discuss the cellular and molecular properties of the retrotrapezoid nucleus (RTN), an integrative and interoceptive control node for the respiratory motor system. We will present the molecular profiling that has allowed definitive identification of a cluster of tonically active neurons that provide a requisite drive to the respiratory central pattern generator (CPG) and other pre-motor neurons. We will discuss the ionic basis for steady pacemaker-like firing, including by a large subthreshold oscillation; and for neuromodulatory influences on RTN activity, including by arousal state-dependent neurotransmitters and CO2/H+. The CO2/H+-dependent modulation of RTN excitability represents the sensory component of a homeostatic system by which the brain regulates breathing to maintain blood gases and tissue pH; it relies on two intrinsic molecular proton detectors, both a proton-activated G protein-coupled receptor (GPR4) and a proton-inhibited background K+ channel (TASK-2). We will also discuss downstream neurotransmitter signaling to the respiratory CPG, focusing especially on a newly-identified peptidergic modulation of the preBötzinger complex that becomes activated following birth and the initiation of air breathing. Finally, we will suggest how the cellular and molecular properties of RTN neurons identified in rodent models may contribute to understanding human respiratory disorders, such as congenital central hypoventilation syndrome (CCHS) and sudden infant death syndrome (SIDS).

The vIRt nucleus in the medulla, composed of mainly inhibitory neurons, is necessary for whisking rhythm generation. It innervates motoneurons in the facial nucleus (FN) that project to intrinsic vibrissa muscles. The nearby pre-Bötzinger complex (pBötC), which generates inhalation, sends inhibitory inputs to the vIRt nucleus which contribute to the synchronization of vIRt neurons. Lower-amplitude periodic whisking, however, can occur after decay of the pBötC signal. To explain how vIRt network generates these “intervening” whisks by bursting in synchrony, and how pBötC input induces strong whisks, we construct and analyze a conductance-based (CB) model of the vIRt circuit composed of hypothetical two groups, vIRtr and vIRtp, of bursting inhibitory neurons with spike-frequency adaptation currents and constant external inputs. The CB model is reduced to a rate model to enable analytical treatment. We find, analytically and computationally, that without pBötC input, periodic bursting states occur within a certain ranges of network connectivities. Whisk amplitudes increase with the level constant external input to the vIRT. With pBötC inhibition intact, the amplitude of the first whisk in a breathing cycle is larger than the intervening whisks for large pBötC input and small inhibitory coupling between the vIRT sub-populations. The pBötC input advances the next whisk and shortens its amplitude if it arrives at the beginning of the whisking cycle generated by the vIRT, and delays the next whisks if it arrives at the end of that cycle. Our theory provides a mechanism for whisking generation and reveals how whisking frequency and amplitude are controlled.

The vagus nerve contains a diversity of sensory neurons that detect peripheral stimuli such as blood pressure changes at the aortic arch, lung expansion during breathing, meal-induced stomach distension, and chemotherapeutics that induce nausea. Underlying vagal sensory mechanisms are largely unresolved at a molecular level, presenting tremendously important problems in sensory biology. We charted vagal sensory neurons by single cell RNA sequencing, identifying novel cell surface receptors and classifying a staggering diversity of sensory neuron types. We then generated a collection of ires-Cre knock-in mice to target each neuron type, and adapted genetic tools for Cre-based anatomical mapping, in vivo imaging, targeted ablation, and optogenetic control of vagal neuron activity. We found different sensory neuron types that innervate the lung and exert powerful effects on breathing, others that monitor and control the digestive system, and yet others that innervate that innervate the larynx and protect the airways. Together with Ardem Patapoutian, we also identified a critical role for Piezo mechanoreceptors in the sensation of airway stretch, which underlies a classical respiratory reflex termed the Hering-Breuer inspiratory reflex, as well as in the neuronal sensation of blood pressure and the baroreceptor reflex.