SYP and Alzheimer disease: As such, a decrease in synaptophysin expression was measured in the CA1 region of 18‐month TgF344‐AD rats compared to 18‐month wild‐types (mean = 0.19, 95% CI = [0.17, 0.21] vs 0.14, 95% CI = [0.13, 0.16] a.f.u., P = 0.016).