Humans are born with all the nerve cells they will ever have, and in each of those nerve cells live about two million mitochondria — tiny power generators that keep the cell functioning properly. As mitochondria age or become dysfunctional, the cell systematically removes them and replaces them with newer models.

Neurobiologist Chantell Evans, Ph.D., wants to know more about this complex process. “How does the cell know how to maintain all of those mitochondria? How does it keep track of who is healthy, who's damaged, who needs to be replaced, and how many new mitochondria need to be made?” she says.

Disruptions in the elaborate system can lead to nerve cell dysfunction and death, which contributes to neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease.