Pertaining to PD, one striking difference between the zebrafish and mammalian models is the location of the PD locus, which was known historically in the ventral mesencephalon or the midbrain, whereas in the zebrafish, the locations are in the PT of the diencephalon with void TH cell clusters in their mesencephalon (Wullimann and Rink, 2002; Filippi et al., 2010; Yamamoto et al., 2010; Hain et al., 2016). Here, TH is linked to Parkinson disease.