An international team of researchers has found that injecting older mice with cerebrospinal fluid from younger mice can lead to an improvement in memory. In their paper published in the journal Nature, the group describes a technique to remove small amounts of cerebrospinal fluid from young mice and inject it into the brain of an older mouse without causing damage. Miriam Zawadzki and Maria Lehtine with Boston Children’s Hospital have published a News & Views piece in the same journal issue outlining the work done by the team in this new effort.