These images show hippocampal tissue sections from HIV-negative (upper panel) and HIV-positive (lower panel) individuals triple-labeled for Aβ oligomers (red), MAP2 (green), and nuclei (blue). Red and green colocalization appears yellow. Aβ oligomers are elevated in HIV-positive brains. For more information, see the article by Stern et al. (pages 4288–4300).