Integration of GABAergic interneurons into cortical cell assemblies: lessons from embryos and adults

In the forebrain, cortical structures consist of networks of excitatory and inhibitory neurons born in distant locations. Understanding how these two major classes of neurons integrate into unique functional cell assemblies may shed light on the organization of cortical circuits. In this review, we provide an overview of the mechanisms used by GABAergic interneurons to reach their final position, with an emphasis on the final steps of this process. To this end, we analyze similarities and differences between the integration of GABAergic interneurons in the developing cerebral cortex and in the postnatal brain, using the neocortex and the olfactory bulb as model systems.