Brown Cells (IMAGE) Neural Regeneration Research Caption Brown cells are terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells undergoing apoptosis (× 400). Credit <i>Neural Regeneration Research</i> 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.