A hereditary and sporadic condition which is characterized by progressive nervous system dysfunction: Neurodegenerative diseases are often associated with atrophy of the affected central or peripheral nervous system structures.

A is one of varied assortments of central nervous system disorders characterized by gradual and progressive loss of neural tissue:

The ability to operate on individual brain cells without killing them in the process could allow scientists to study how the cells regenerate and might lead to better treatments for neurodegenerative diseases such as Alzheimer's and Parkinson's.