Prediction errors disrupt hippocampal representations and update episodic memories

• DOI: 10.1073/pnas.2117625118
• Publication Date: 2021-12-15T21:56:21Z
• Authors: Alyssa H. Sinclair; Grace M. Manalili; Iva K. Brunec; R. Alison Adcock; Morgan D. Barense
• Keywords: Adult; Male; 0301 basic medicine; Adolescent; Memory, Episodic; Middle Aged; Hippocampus; Magnetic Resonance Imaging; 12. Responsible consumption; Young Adult; 03 medical and health sciences; Prosencephalon; 0302 clinical medicine; Mental Recall; Humans; Female; Nerve Net

Significance Our brains draw on memories to predict the future; when our predictions are incorrect, we must update our memories to improve future predictions. Past studies have demonstrated that the hippocampus signals prediction error (i.e., surprise) but have not linked this neural signal to memory updating. Here, we uncover this missing connection. We show that mnemonic prediction errors change the role of the hippocampus, reversing the relationship between hippocampal activation and memory outcomes. We examine the mechanisms of this shift in neural processing, showing that prediction errors disrupt the temporal continuity of hippocampal patterns. We propose that prediction errors disrupt sustained representations and enable memory updating. Our findings bear implications for improving education, understanding eyewitness memory distortion, and treating pathological memories.