A Systematic Review and Meta-analysis of the Neural Correlates of Direct vs. Generative Retrieval of Episodic Autobiographical Memory

There is a widespread view that episodic autobiographical memories (EAMs) can be retrieved "directly" or "generatively." However, the neural mechanisms underlying these retrieval modes have been overlooked in the literature, likely due to the difficulty of operationalizing the two notions. Here, we propose to operationalize direct vs. generative retrieval based on memory cue specificity, in terms of EAMs elicited by specific/personalized vs. generic memory cues, respectively. After completing a literature search in four databases (PubMed, Scopus, Google Scholar, Web of Science) in 2023, we performed a multilevel kernel density analysis (MKDA) to directly compare activations from 32 neuroimaging studies investigating these two EAM retrieval modalities with the above memory cue distinction. Both direct and generative retrieval showed common activations of the left hippocampus, bilateral angular gyrus, and posterior cingulate cortex. The direct vs. generative comparison revealed the activation of a brain circuit comprising the anterior and posterior cortical midline, the left angular gyrus, and the right cerebellum. Previous literature suggests that these regions play a role in self-referential processes, indicating that direct access to EAMs may be supported by the recruitment of self-related neural resources that facilitate the retrieval of personal memories. Conversely, generative vs. direct MKDA revealed the activation of the ventromedial prefrontal cortex. As this region has been previously associated with schematic memory, its involvement may emphasize the "constructive" nature of generative EAM retrieval. Overall, the current findings extend the previous literature by providing the neurobiological foundation of direct and generative EAM retrieval.