This image shows amyloid plaques (blue, methoxy-X04) surrounded by dystrophic, swollen axons that accumulate lysosome precursors (green, anti-Lamp1) in cortex of a mouse model of Alzheimer's disease (PS2APP mouse). Microglia (red, anti-Iba1) also cluster around the plaques and limit axonal damage. Loss of TREM2, a gene linked to Alzheimer's disease risk and expressed by microglia, elevates the level of soluble Aβ in its toxic forms and exacerbates the axonal damage. For more information, see the article by Meilandt et al. (pages 1956–1974).