Alzheimer's Brain Tissue (IMAGE) Rutgers University Caption In a human brain tissue sample with Alzheimer's disease, the brown Cdk5 is in the nucleus of the five cells in the upper center. In the three cells (arrows) with red nuclei, the brown Cdk5 is just outside the nucleus. The red means that the neuron is trying to divide and is hence on its way to die. Credit Karl Herrup, Rutgers University 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.