TY - JOUR T1 - Network-wide abnormalities explain memory variability in hippocampal amnesia JF - bioRxiv DO - 10.1101/551812 SP - 551812 AU - Georgios P. D. Argyropoulos AU - Clare Loane AU - Adriana Roca-Fernandez AU - Carmen Lage-Martinez AU - Oana Gurau AU - Sarosh R Irani AU - Christopher R Butler Y1 - 2019/01/01 UR - http://biorxiv.org/content/early/2019/06/29/551812.abstract N2 - Patients with hippocampal amnesia play a central role in memory neuroscience but the neural underpinnings of amnesia are hotly debated. We hypothesized that focal hippocampal damage is associated with changes across the extended hippocampal system and that these, rather than hippocampal atrophy per se, would explain variability in memory between patients. We assessed this hypothesis in a uniquely large cohort of patients (n=38) after autoimmune limbic encephalitis, a syndrome associated with focal structural hippocampal pathology. These patients showed impaired recall, recognition and maintenance of new information, and remote autobiographical amnesia. Besides hippocampal atrophy, we observed correlatively reduced thalamic and entorhinal cortical volume, resting-state inter-hippocampal connectivity and activity in posteromedial cortex. Associations of hippocampal volume with recall, recognition, and remote memory were fully mediated by wider network abnormalities, and were only direct in forgetting. Network abnormalities may explain the variability across studies of amnesia and speak to debates in memory neuroscience. ER -