qRT-PCR analysis of SNCA expression following in vivo RNAi. SNCA siRNA (syn-siRNA), luciferase siRNA (luc-siRNA), or PBS was infused into the right CA1. qRT-PCR was used to determine expression of SNCA following RNAi in treated right side compared to the untreated contralateral side (R:L ratio). SNCA siRNA had a statistically significant decrease of SNCA expression in the right compared to the left side of the brain, and R:L ratios were decreased when compared to controls (vs PBS, p = 0.036; vs. luciferase, p = 0.004). Horizontal lines show medians. Open circles indicate mice in which the cannula was disconnected during treatment or did not function.