Conclusion In the early stage, MSA is shown the degeneration of neuron is mild, and the lesion of axon is the main pathological changes. The PV (+) neuron in the dentate nucleus may due to the cell protective reaction. 结论MSA早期小脑的病变是以轴索病变为主而神经元变性则较轻,并且在齿状核出现的PV(+)神经元可能是一种细胞保护性反应。