(A) study on the neural representation of memory confidence in the hippocampus and prefrontal cortex

Abstract

Memory confidence is a metacognitive process that evaluates memory. Our responses or decisive actions can be facilitated or delayed depending on the level of memory confidence. Previous studies have suggested that memory confidence is dissociable from memory accuracy and that the activity of the prefrontal cortex and medial temporal lobe is associated with memory confidence processes. However, neural information processing underlying memory confidence remains unclear. To address this, here we investigated memory confidence-related neural processing in the hippocampus and the prefrontal cortex, using event-related functional magnetic resonance imaging (fMRI). We found high confidence-specific neural representations in the CA3/DG and ventromedial prefrontal cortex (vmPFC) for true memories but not for false memories. Moreover, overgeneralization of object representation in the dorsolateral prefrontal cortex (dlPFC) and vmPFC was found when participants had a high level of confidence in their false memories. These findings suggest that both the shared and differential neural substrates are utilized in the confidence processes of true and false memories, and that the confidence process of false memories is based on generalization processing in the prefrontal cortex while true memory confidence process is based on memory processing in the hippocampus.