The Contribution of the Ganglionic Eminence to the Neuronal Cell Types of the Cerebral Cortex

The principal neuronal types of the mammalian cerebral cortex are the excitatory pyramidal cells and the inhibitory interneurons, the non-pyramidal cells. It is thought that these neurons arise in the ventricular zone surrounding the telencephalic ventricles. From there, newly generated neurons migrate outward along the processes of radial glial cells to reach the cortical plate where they accumulate in an 'inside-out' sequence to form the six-layered structure of the neocortex. Here we review emerging evidence that pyramidal neurons are generated in the cortical ventricular zone, whereas the majority of the non-pyramidal cells arise in the ganglionic eminences of the ventral telencephalon. These neurons follow tangential migratory routes to reach their positions in the developing cortex.