Activation of stimulus-specific processing regions at retrieval tracks the strength of relational memory

Brain activity patterns underlying memory confidence

The primary aim of this review is to examine the brain activity patterns that are related to subjectively perceived memory confidence. We focus on the main brain regions involved in episodic memory: the medial temporal lobe (MTL), prefrontal cortex (PFC), and posterior parietal cortex (PPC), and relate activity in their subregions to memory confidence. How this brain activity in both the encoding and retrieval phase is related to (subsequent) memory confidence ratings will be discussed. Specifically, encoding related activity in MTL regions and ventrolateral PFC mainly shows a positive linear increase with subsequent memory confidence, while dorsolateral and ventromedial PFC activity show mixed patterns. In addition, encoding-related PPC activity seems to only have indirect effects on memory confidence ratings. Activity during retrieval in both the hippocampus and parahippocampal cortex increases with memory confidence, especially during high-confident recognition. Retrieval-related activity in the PFC and PPC show mixed relationships with memory confidence, likely related to post-retrieval monitoring and attentional processes, respectively. In this review, these MTL, PFC, and PPC activity patterns are examined in detail and related to their functional roles in memory processes. This insight into brain activity that underlies memory confidence is important for our understanding of brain-behaviour relations and memory-guided decision making.

Retrospective confidence judgments: Meta-analysis of functional magnetic resonance imaging studies

Confidence in our retrieved memories, that is, retrospective confidence, is a metamemory process we perform daily. There is an abundance of applied research focusing on the metamemory judgments and very diverse studies including a wide range of clinical populations. However, the neural correlates that support its functioning are not well defined impeding the implementation of noninvasive neuromodulatory clinical interventions. To address the neural basis of metamemory judgments, we ran a meta‐analysis, where we used the activation likelihood estimation method on the 19 eligible functional magnetic resonance imaging studies. The main analysis of retrospective confidence revealed concordant bilateral activation in the parahippocampal gyrus, left middle frontal gyrus, and right amygdala. We also run an analysis between the two extreme levels of confidence, namely, high and low. This additional analysis was exploratory, since the minimum amount of articles reporting these two levels was not reached. Activations for the exploratory high > low confidence subtraction analysis were the same as observed in the main analysis on retrospective confidence, whereas the exploratory low > high subtraction showed distinctive activations of the right precuneus. The involvement of the right precuneus emphasizes its role in the evaluation of low confidence memories, as suggested by previous studies. Overall, our study contributes to a better understanding of the specific brain structures involved in confidence evaluations. Better understanding of the neural basis of metamemory might eventually lead to designing more precise neuromodulatory interventions, significantly improving treatment of patients suffering from metamemory problems.