Prediction errors disrupt hippocampal representations and update episodic memories.

Area of Science:

• Neuroscience
• Cognitive Psychology
• Memory Research

Background:

• The brain uses predictions and prediction errors to learn and update memories.
• The hippocampus is known to signal prediction errors, but its role in memory updating remains unclear.

Purpose of the Study:

• To investigate the link between hippocampal prediction error signals and memory updating.
• To explore how prediction errors influence memory consolidation and modification.

Main Methods:

• A human functional MRI study was conducted.
• Mnemonic prediction errors were induced by interrupting familiar narrative videos before their expected conclusions.
• Hippocampal activation patterns and connectivity with neuromodulatory regions were analyzed.

Main Results:

• Prediction errors altered the relationship between hippocampal activation and memory.
• Higher hippocampal activation correlated with memory preservation for expected events but memory updating for surprising events.
• Disruption of sustained hippocampal activation patterns by prediction errors predicted memory updating.
• Basal forebrain activation modulated the relationship between hippocampal activity and memory.

Conclusions:

• Prediction errors create conditions conducive to memory updating.
• The hippocampus abandons ongoing predictions and enhances memory malleability in response to surprising events.
• Cholinergic modulation from the basal forebrain plays a role in regulating attention and memory during prediction error processing.