RB1 and Parkinson disease: Although we found that Rb1 changed α-synuclein expression in the primary cultured hippocampal neuron in vitro and in the hippocampus of PD animal model, we did not find Rb1 treatment changed the cognitive performance in the normal mice, and we also did not find Rb1 treatment changed the hippocampal α-synuclein expression in the normal mice.