APOE and Alzheimer disease: In order to study the diverse effects that APOE4 expression has on the brain, we performed a transcriptomics analysis on the entorhinal cortex (EC) and primary visual cortex (PVC) of 14–15 month-old APOE targeted replacement mice, which express human APOE in place of their mouse Apoe gene and which do not develop overt AD pathology28,29.