Distinct generation of subjective vividness and confidence during naturalistic memory retrieval in angular gyrus

Abstract

Subjective experience of remembering is a hallmark of episodic memory, which enables us to monitor experiences, identify mistakes, and adjust our decisions accordingly. A fundamental and enduring puzzle is the origin of confidence in memory; for example, does the confidence during episodic retrieval depend upon the subjective sensed vividness, or does confidence and vividness reflect dissociable introspective processes? The angular gyrus (AnG) exhibits a sensitivity to subjective experience of remembering, but its direct contribution to the monitoring of internal subjective mnemonic experience has hitherto been lacking. Here we combined a novel naturalistic video-watching paradigm with repetitive transcranial magnetic stimulation (rTMS) and resting-state functional magnetic resonance imaging (fMRI) to test the idea that vividness and confidence are generated differently during retrieval. We found that pre-retrieval rTMS targeting the left AnG selectively alters the vividness efficiency compared to control stimulation while keeping metacognitive efficiency and objective memory accuracy unaffected. Using trial-wise data, we showed that vividness mediates the association between confidence and objective memory accuracy and such mediation was eradicated by AnG stimulation. Furthermore, resting-state functional connectivity of hippocampus and AnG was specifically associated with vividness efficiency, while the connectivity of hippocampus and medial prefrontal cortex was associated with metacognitive efficiency across individuals. These findings identify a role for the AnG in gauging the vividness, but not the confidence, of memory, thereby providing evidence for a differentiation account of conscious assessment of memory by functionally and anatomically dissociating the monitoring of vividness from confidence.

Episodic memory precision and reality monitoring following stimulation of angular gyrus

“…The observation that stimulation of angular gyrus selectively reduced the link between memory precision and self-referential reality monitoring decisions is consistent with proposals that functioning of angular gyrus may contribute to the self-referential quality of memories (Bonnici et al, 2018;Rugg & King, 2018;Weniger et al, 2009;Yazar et al, 2012Yazar et al, , 2014Yazar et al, , 2017. This selfreferential mnemonic function may involve integrating multiple modalities of retrieved features, such as visual and auditory details (Yazar et al, 2017), within an egocentric, first-person perspective framework (Bonnici et al, 2018), in order to reconstruct rich and subjectively vivid mnemonic representations that are imbued with a sense of self-agency (Simons et al, 2021;Zou & Kwok, 2021).…”

Episodic Memory Precision and Reality Monitoring Following Stimulation of Angular Gyrus

“…Turning to the possible neurocognitive basis of memory precision and reality monitoring, stimulation of angular gyrus selectively reduced the observed link between memory precision and self-referential reality monitoring decisions, consistent with proposals that functioning of angular gyrus may contribute to the self-referential quality of memories (Bonnici et al, 2018;Rugg & King, 2018;Weniger et al, 2009;Yazar et al, 2012Yazar et al, , 2014Yazar et al, , 2017. This self-referential mnemonic function may involve integrating multiple modalities of retrieved features, such as visual and auditory details (Yazar et al, 2017), within an egocentric, first-person perspective framework (Bonnici et al, 2018), in order to reconstruct rich and subjectively vivid mnemonic representations that give rise to a sense of self-agency (Simons et al, 2022;Zou & Kwok, 2021).…”

Adding meaning to memories: How parietal cortex combines semantic content with episodic experience

“…Another issue that is beyond the scope of the current study is the degree to which the effects reported here depend on the subjective experience of remembering versus the objective experience of stimulus repetition. A compelling body of evidence indicates that the angular gyrus is involved in (Hutchinson et al, 2014; Kuhl & Chun, 2014; Ramanan et al, 2018) and even necessary for (Simons et al, 2010; Tibon et al, 2019; Yazar et al, 2014; Zou & Kwok, 2022) the subjective experience of remembering. In contrast, memory effects in OTC may be more closely related to objective effects of stimulus repetition (Sayres & Grill-Spector, 2006; Ward et al, 2013).…”