MAPT and Alzheimer disease: Furthermore, functional connectivity between the RSC and HPC is associated with medial parietal tau, thus suggesting that tau in the HPC spreads directly to the medial parietal lobe via connectivity with the RSC.36 The combination of greater medial parietal lobe tau accumulation and greater RSC-HPC strength is also related to episodic memory performance.36 Taken together, it is therefore plausible that disrupted functional connectivity between the RSC and HPC may partially underlie early episodic memory deficits in the Alzheimer’s disease spectrum via tau spreading and accumulation.