Brain image (IMAGE) Penn State Caption Biomedical engineering researchers discovered that during rest, individual neurons fire in organized cascades, triggering activity across the brain. Here, the spiking activity of five individual neurons is shown in a section of a mouse brain. Credit Xiao Liu, Penn State Usage Restrictions non commercial use only 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.