Oxidative stress is a prominent feature of Alzheimer's disease. Within this context, cholesterol undergoes oxidation, producing the pro-inflammatory product 7-ketocholesterol (7-KC). In this study, we observe elevated levels of 7-KC in the brains of the 3xTg mouse model of AD. To further understand the contribution of 7-KC on the oxidative environment, we developed a method to express a genetically encoded fluorescent hydrogen peroxide (H