Dynorphin Neurons (image) Washington University School of Medicine Share Print E-Mail Caption In brain cells, a neurotransmitter (in red) is known to activate aversion behavior, but Washington University neuroscientists have found that in cells just a millimeter away the same neurotransmitter can activate reward behavior. The close proximity of the cells may help explain why drugs for addiction and depression are not always effective. Credit Bruchas laboratory, Washington University Usage Restrictions None 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.