MAPT and Alzheimer disease: Previous research has linked spatial navigation performance to AD-specific biomarkers, including CSF Aβ1–42 and phosphorylated tau181 (p-tau181) levels [9, 15, 18], biomarkers of neurodegeneration, including CSF total tau (t-tau) and neurofilament light levels [15, 18], and atrophy in AD-related brain regions.