Angular gyrus involvement at encoding and retrieval is associated with durable but less specific memories

After consolidation, information belonging to a mental schema is better remembered, but such memory can be less specific when it comes to details. A neuronal mechanism in line with this behavioral pattern could result from a dynamic interaction that entails mediation by a specific cortical network with associated hippocampal disengagement. We now report that in male and female adult human subjects, encoding and later consolidation of a series of objects embedded in a semantic schema was associated with a build-up of activity in the angular gyrus (AG) that predicted memory 24h later. In parallel, the posterior hippocampus became less involved as schema objects were successively encoded. Hippocampal disengagement was related to an increase in falsely remembering objects that were not presented at encoding. During both encoding and retrieval, the AG and lateral occipital complex (LOC) became functionally connected and this interaction was beneficial for successful retrieval. Thus, a network including the AG and LOC enhances the overnight retention of schema-related memories, and their simultaneous detachment from the hippocampus reduces the specificity of the memory