Synapses are postulated to be the main site of aSN pathology in PD; most of both aSN monomer and aggregated aSN locate at the synapse.[47] Synaptic dysfunction is often observed to precede neurodegeneration and could be caused by either intra- or extracellular αSOs.[48] Fig 5 (top) demonstrates that extracellular DHA- and HNE-αSOs bind primary hippocampal neurons (stained with antibodies against MAP2 which is found in neurites and cell bodies) in a specific punctate pattern. Here, MAP2 is linked to Parkinson disease.