SNCA and multiple system atrophy: From the perspective of functional integration, the hypothesis of “disconnection syndrome” indicated that the accumulation of alpha-synuclein may damage the specific functional connectivity networks including the striatal-thalamo-cortical (STC) and cerebello-thalamo-cortical (CTC), causing corresponding functional disorders of MSA (Yao et al., 2017; Rosskopf et al., 2018).