More Mature (image) Brown University Share Print E-Mail Caption By 28 days of age, many dark brown parvalbumin interneurons had developed in tissue from a stress-exposed mouse on the right, but they had yet to develop in the unstressed mouse on the left. Credit Bath et. al./Brown University Usage Restrictions with credit Share Print E-Mail 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.