SV2A and Parkinson disease: The tracer [11C]UCB-J was further tested by visualization in vivo as a marker of synaptic SV2A density loss in rats with unilateral striatal lesions using 6-hydroxydopamine (6-OHDA) to model toxin-induced Parkinson’s disease (Thomsen et al., 2021b) or preformed α-synuclein fibrils to model progressive Parkinson’s disease (Thomsen et al., 2021a).