Cortical GABAergic interneurons constitute a highly diverse population in terms of embryonic origin, molecular identity, morphological and connectivity features, electrophysiological properties and laminar distribution. This large cellular diversity makes it difficult to study the specific function of inhibitory interneuronal subtypes in cortical microcircuits. Approximately 30% of cortical GABAergic interneurons are classified based on the expression of a specific serotoninergic receptor, the ionotropic serotonin receptor 5HT3a (Htr3a) and are often studied using the Htr3a-GFP mouse line. This population of Htr3a-expressing interneurons mainly arises from the embryonic caudal ganglionic eminence (CGE) and the study of its large diversity is a main focus of our laboratory...