Schematic illustration of E14 and E18 chicken embryo brain. (A) Embryos at intermediate development stage E14. (B) Embryos at late development stage E18. HP, hippocampus; APHm, the medial part of APH; APHi, the intermedial part of APH; APHl, the lateral part of APH; APHcl, the caudolateral part of APH; S, the superficial layer; C, the cortical plate; PV, the periventricular layer. Dashed lines indicate the division between subregions and layers.