APP23 transgenic mice, which express human APP751 familial Swedish mutation (K670N/M671L) under the control of the mouse Thy-1 promoter, begin accumulating parenchymal Aβ at ~6 months-of-age, although cognitive decline in this AD mouse model precedes extracellular Aβ deposition and can be observed at 3 months-of-age [36, 37]. Here, THY1 is linked to Alzheimer disease.