Amphibians hold a significant place in evolution, representing the transition from aquatic to terrestrial lifestyles. They are crucial for understanding the brain and spinal cord of tetrapods—animals with four limbs, including humans. A group of scientists led by a team at the Institute of Science and Technology Austria (ISTA) now shows how harmless viruses can be used to illuminate the development of the frog nervous system. The results have now been published in Developmental Cell.