GABAergic interneurons shape the spatial and functional organization of cortical networks. While many studies have elucidated the physiology and connectivity of single interneurons, the spatiotemporal relationship of the activity of groups of interneurons and its relation to population dynamics remain unclear. In order to untangle how interneurons interact with each other and probe their influence on the spatio-temporal organization of cortical dynamics, we have used an all-optical approach combining two-photon calcium imaging with computer-generated holographic light stimulation of soma-targeted opsins in awake mice during development and into adulthood. Similar experiments have so far focused on probing the impact of functionally tuned glutamatergic neurons of the visual cortex (Chettih 2019). In this talk, I will present data indicating that they single-handedly exert a significant modulation on the activity of their functional partners, both in the adult and developing cortex.
Rosa Cossart is the Director of the Institute of Mediterranean Neurobiology (INMED), affiliated to INSERM and Aix-Marseille University, a pioneering Institute in the field of Systems Developmental Neuroscience. After graduating in Mathematics and Physics from the Ecole Centrale Paris, she studied the functional rewiring of GABAergic circuits in epilepsy during her PhD with Drs. Bernard and Ben-Ari. As a postdoctoral fellow with Pr. Yuste at Columbia University, she pioneered the use of calcium imaging to study cortical circuit function. Her lab made seminal contributions to the understanding of how development scaffolds hippocampal circuits. They discovered “hub cells” and more recently “assemblies” forming the functional building blocks of hippocampal function.