ACHE and Parkinson disease: Few PET studies with [11C]methyl-4-piperidinyl propionate acetylcholinesterase ([11C]PMP) (Gilman et al., 2010) but not others (Shinotoh et al., 1999; Bohnen et al., 2006, 2010) described a reduced striatal cholinergic activity in patients with PD.