Zebrafish—striped fish a few centimeters long—have the ability to regrow up to 20 percent of their hearts after sustaining major damage. Research published in the journal eLife, done in the lab of Marianne Bronner, Albert Billings Ruddock Professor of Biology, director of the Beckman Institute and affiliated faculty member of the Tianqiao and Chrissy Chen Institute for Neuroscience at Caltech, has now discovered that embryonic cells from the hindbrain, called neural crest cells, migrate to the developing heart and form heart muscle in zebrafish and other species. After an adult zebrafish’s heart is damaged, these cells participate in heart regeneration by reverting back to an embryonic-like state and proliferating to help repair the injury.