Intrastriatal injections of an AAV vector expressing TH and GCH1 at 9E8 gc results in a small number of TH positive neuronal profiles in the striatum and in globus pallidus (C). Increasing the vector dose to 5E9 gc (D) resulted in larger transduction area in the striatum and further spread to globus pallidus and cortex. Injection of 1E10 and 1E11 gc gave more widespread transduction not only in the striatum but also more extensive expression in the globus pallidus and overlying cortex (E,F). ctx = cortex, cc = corpus callosum, gc = genomic copies, gp = globus pallidus, lv = lateral ventricle, str = striatum. Scale bar in a represent 0.2 mm in all panels.