Rat's Hippocampus (IMAGE) Johns Hopkins University Caption Research assistant Jeremy Johnson feeds a rat on the behavioral track used to determine where the brain decides what is new and what is familiar. Credit Johns Hopkins University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.