© Springer Japan 2015. Twenty-first century research and development into neuroscience has brought about new methodologies that can be used to investigate the biological basis of neurodegenerative diseases and to provide new insights into understanding neurodegenerative diseases. There is a recognition that functional and structural networks across the neural system and other biological systems in the human body may affect the occurrence and ingravescence of neurodegenerative diseases. There is also suggestion that diseases which were once considered to be different or independent may have closer relationship. Thus, it can confidently be said that neurodegenerative diseases are caused not only by the direct deficit of brain and nerves, but also by the effect on the neural system by deficits in other functional systems in the human body. This idea provides researchers with a new biological approach to neurodegenerative diseases. Various clinical studies will be conducted for subjects with neurodegenerative diseases in the near future on this basis. From the perspective of bioethics research, this chapter discusses current issues and future views regarding the research and development of treatment technology for neurodegenerative diseases by focusing on protection of the subject.