Neuropathology of Parkinson's Disease

This chapter focuses on the neuropathology of Lewy body (LB) Parkinsonism. The chapter also discusses about the importance of Parkinson's disease (PD) models for understanding the pathogenesis of the disease and for developing therapeutics. Many of the current animal models focus on one of the two aspects of the pathology of PD-either α-synuclein pathology or pathology in the nigrostriatal dopaminergic pathway. Cellular and transgenic animal models tend to focus on the former, while toxin models tend to be more appropriate to the latter. Both approaches have their strengths and weaknesses. The challenge of animal models is to accurately replicate not only the morphologic aspects of the disease, but also the selective vulnerability and neurodegeneration. None of the available models shows neurodegeneration in all of the brain regions that are commonly affected in PD. An essential neuropathologic feature of PD is not only α-synuclein pathology, but also neuronal loss and gliosis. This chapter covers the subject of gross and microscoping findings in PD. Neuropathologic staging of PD is explained in detail in this chapter. The chapter also examines LBs in other disorders. Molecular biology of LBs and neuronal loss in PD is discussed. The chapter concludes with a discussion on relevance of neuropathology to PD models.