Fig. 2. Ahd2 expression is restricted to the lateral part of the mdDA during the late differentiation phase. Distribution of Ahd2 mRNA in sagittal E13.5 sections from the lateral to medial part of the meso-diencephalic dopaminergic (mdDA) area containing neurons in the presumptive substantia nigra pars compacta (SNc) and ventral tegmental area (VTA), respectively. The cell bodies of the fully differentiated mdDA neurons were identified by Th mRNA expression, and Ahd2 expression was analyzed on the adjacent sections. Expression of Aadc on the adjacent sections identified, in addition to the fully differentiated mdDA neurons, young migrating DA neurons located more dorsally. 3V, third ventricle; 4V, fourth ventricle; Aq, aqueduct; MF, mesencephalic flexure.