With MAO-B be used as a biochemical imaging marker for astrocyte activation in the human brain, a post-mortem study on parkinsonian dopamine deficiency disorders showed both astrocyte markers (GFAP, vimentin, Hsp27) and MAO-B levels were increased and significantly correlated in the putamen of patients with multiple system atrophy (MSA); the same results were observed in the substantia nigra of patients with progressive superanuclear palsy (PSP). Here, MAOB is linked to multiple system atrophy.