As a neurologist, specialized in clinical neurophysiology/epileptology, and as a neurobiologist/electrophysiologist, my research aims at deciphering dysfunctions of neuronal behavior and interactions in neurological diseases, both at the level of the electrophysiological signal they produce and at the level of synaptic signaling. We focus on epilepsy, characterized by chronic rearrangements of neurons and connections, and by interaction with lesions such as tumors. Multiscale recordings allow identification of electrophysiological signatures which provide data on neuronal dysfunctions, ranging from abnormal neuronal properties, synaptic signaling to the buildup of abnormal networks. We explore how interneurons turn out to trigger epileptic activities, GABA displaying paradoxical excitatory effects related to chloride (Cl-) dysregulation in epileptic tissues. We study gliomas, brain tumors formed by networks of connected tumor cells, nested in and interacting with neuronal networks. Oncometabolites produced by tumor cells and neurotransmitters affect both the generation of epileptic activities by neurons and the growth of glioma cells through synaptic-related mechanisms. To assess such electrophysiological signals and synaptic signaling, we work mostly on human material, from patients in vivo recordings to postoperative tissues recording and cultures. Our group further co-develops innovative electrodes for cortical recordings with high spatio-temporal resolution and Ultrasound devices for neurostimulation.