The origins and specification of cortical interneurons

Interneurons, also termed local circuit neurons or (by Cajal) neurons with short axons (DeFelipe and Jones (1988) Cajal on the Cerebral Cortex. Oxford University Press, New York), are found throughout the neuraxis. Interneuron function is diverse, ranging from excitation or inhibition to network synchronization, and they accomplish these functions through a wide diversity of neuronal types that differ by neurotransmitter, neurochemical profile, axonal or dendritic arborizations, and targets. With advances in transgenic mouse and other technologies, recent years have produced tremendous advances in understanding interneuron development, function, and relation to human disease. While these advances have come at all levels of central nervous system, this chapter focuses on cerebral cortical interneuron development that is most relevant to human cognition as well as various mental and neurological disorders.