MAPT and hippocampal atrophy: The amount of total tau (T-tau) in CSF correlates with the intensity of neurodegeneration (Gao et al., 2018) and hyperphosphorylated tau (P-tau) levels in CSF correlate with hippocampal atrophy in prodromal AD (De Leon et al., 2006; Fagan and Holtzman, 2010).