Researchers identify the trigger of key cellular change in amyotrophic lateral sclerosis Scientists at the Francis Crick Institute and UCL have identified the trigger of a key cellular change in amyotrophic lateral sclerosis (ALS), a type of motor neurons disease. The findings could help develop new treatments for many neurological diseases with the same change, including Parkinson's and Alzheimer's. When the nervous system is injured, diseased or infected, star-shaped cells, called astrocytes, undergo 'reactive' changes in their behavior. Whilst some of these reactive astrocytes become protective, others become harmful and damage surrounding motor neurons. Reactive astrocytes are observed in various neurodegenerative diseases including ALS, but there is a lack of understanding about what causes astrocytes to undergo this change.