What are neurodegenerative diseases and how might they be treated?

Neurodegenerative diseases that include Alzheimer's, Parkinson's, Huntington's, and amyotrophic lateral sclerosis (ALS), are all marked by progressive degeneration and death of nerve cells in distinct regions of the brain. Scientists have identified a few common neurodegenerative disease mechanisms. For instance, each of these conditions involves "protein aggregation," abnormal build-up of certain proteins in the brain (for example amyloid in Alzheimer's). Each also seems to target specific subsets of nerve cells, like dopamine cells in Parkinson's, or motor neurons in ALS and Huntington's. Mechanisms like oxidative stress, inflammatory processes, and "cell suicide," or apoptosis, may also be part of the problem in each of these diseases.