TH and memory impairment: To correlate the 6-DOT memory impairment observed in SNpc-hu-α-Syn mice in the LT experiment with biochemical changes in the hippocampus, we performed Western blot analysis on their hippocampi and found a significant reduction in TH protein expression (Fig. 2e), which was associated with reduced expression of D1 dopamine receptor (D1DR) (Fig. 2f).