brain organoid (IMAGE) University of California - San Diego Caption A representative culture from a brain organoid in which the gene MECP2 — causative in Rett syndrome — has been "knocked out," as shown through a fluorescent microscope. Because the culture was treated with experimental cancer drug ADH-503, new synapses formed. Credit Muotri Lab/ UC San Diego Health Sciences Usage Restrictions use photo credit License Original 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.