Based on prior reports of reduced diurnal activity rhythm amplitudes in DS, AD, aging individuals, and animal models thereof [24, 31, 36, 56, 57], each of which exhibit RCAN1 upregulation, and in sra KO flies, which lack the Drosophila homolog of RCAN1 [49], we hypothesized that RCAN1 also regulates the rhythmicity of wheel running. Here, RCAN1 is linked to Alzheimer disease.