Metabolic Activity in the Hippocampus (image) Cell Press Caption Metabolic activity (green and red colors) in the hippocampus (white dotted line) of animals that underwent extinction training in combination with HDACis (right) is significantly higher than in animals that underwent extinction training alone (left). Metabolic activity serves to estimate the learning capacity of an animal. Credit Cell, Gräff et al. Usage Restrictions Credit Required 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.