Moreover, the Sox6+ and ALDH1A1+ populations exist in the human ventral SNpc and are selectively diminished in postmortem PD brains.[8] In the current work, we show that AEP is activated in midbrain DA neurons by α‐Syn fibrils in the SNpc that circuit to the locus coeruleus (LC) via axon projection; in contrast, there is much less neural circuitry between the VTA and LC or dorsal motor vagus nerve (DMVN) in the brain stem. This evidence concerns the gene ALDH1A1 and Parkinson disease.