**Acknowledgements**

This chapter is funded by NIH R01 NS092865. We are grateful to all participants and their families for their commitment and dedication to advance research of diagnosis and treatment for PD and AD as well as to the Knight-ADRC and MDC research staff for their contributions. We thank Dr. Nigel Cairns, Ms. Erin E. Franklin, and Mr. Michael Baxter for coordination of the tissue preparation and expert technical assistance. We also thank Mr. William Knight for editorial assistance.
