Mash1 is the only gene expressed in the ventral telencephalon. It is found in the dorsal telencephalon in fetuses. The prosencephalon develops further into the telencephalon and the diencephalon. Emx1 is expressed in most cortical neurons within the developing telencephalon. The prosencephalon gradually divides into the telencephalon and the diencephalon. However, the SVZ of the ventral telencephalon persists throughout life. The subpallium is the ventral telencephalon. Emx1 gene expression is constricted to the dorsal telencephalon. The cerebral hemispheres are derived from the telencephalon. The non-pallial part of the telencephalon builds the subpallium. The escape response has been found to be processed in the telencephalon. In vertebrates, the avoidance behaviour appears to be processed in the telencephalon. The insular cortex is considered a separate lobe of the telencephalon by some authorities. The embryonic telencephalon is subdivided into dorsal pallium and ventral subpallium. The subthalamus connects to the globus pallidus, a basal nucleus of the telencephalon.