Functional and Effective Hippocampal–Neocortical Connectivity During Construction and Elaboration of Autobiographical Memory Retrieval

Abstract

Autobiographical memory (AM) provides the opportunity to study interactions among brain areas that support the search for a specific episodic memory (construction), and the later experience of mentally reliving it (elaboration). While the hippocampus supports both construction and elaboration, it is unclear how hippocampal-neocortical connectivity differs between these stages, and how this connectivity involves the anterior and posterior segments of the hippocampus, as these have been considered to support the retrieval of general concepts and recollection processes, respectively. We acquired fMRI data in 18 healthy participants during an AM retrieval task in which participants were asked to access a specific AM (construction) and then to recollect it by recovering as many episodic details as possible (elaboration). Using multivariate analytic techniques, we examined changes in functional and effective connectivity of hippocampal-neocortical interactions during these phases of AM retrieval. We found that the left anterior hippocampus interacted with frontal areas during construction and bilateral posterior hippocampi with visual perceptual areas during elaboration, indicating key roles for both hippocampi in coordinating transient neocortical networks at both AM stages. Our findings demonstrate the importance of direct interrogation of hippocampal-neocortical interactions to better illuminate the neural dynamics underlying complex cognitive tasks such as AM retrieval.

Dissociating patterns of anterior and posterior hippocampal activity and connectivity during distinct forms of category fluency

“…The anterior memory network, which includes the anterior MTLs and frontal regions, is involved in retrieving general constructs and concepts, and the posterior memory network, which includes posterior MTLs and posterior cortical regions, is involved in retrieving perceptual details (Poppenk et al, 2013;Evensmoen et al, 2015). In support of this view, connectivity between the anterior hippocampus and prefrontal cortex was found to be more involved when constructing or accessing personal memories whereas connectivity between the posterior hippocampus and posterior cortical regions, namely the visual cortex, was more involved when elaborating on the details of those memories once they were retrieved (McCormick, St-Laurent, Ty, Valiante, & McAndrews, 2015).…”

“…In thinking about this difference, the results of a recent study by McCormick et al (2015) may be instructive. They found that during the initial, constructive phase of autobiographical event recall, activation was more prominent in the anterior hippocampus and its connectivity pattern resembled that reported in this study.…”

Distinct hippocampal functional networks revealed by tractography-based parcellation

“…Examining all nodes in the DMN, which shows strong overlap with the recollection network, we found that connectivity between the hippocampus and posterior neo-cortical regions was also predictive of better memory performance in temporal lobe epilepsy (McCormick et al 2014). In a study on autobiographical retrieval in healthy adults, we found enhanced connectivity between the postHC and posterior cortical regions when individuals were retrieving perceptual details of events as compared with generating memories from verbal cues (McCormick et al 2013b). Thus, we hypothesized that RIM performance in healthy adults would be positively correlated with the functional connectivity of postHC to the recollection memory network (Rugg and Vilberg 2013).…”

Putting Ourselves in Another’s Skin: Using the Plasticity of Self-Perception to Enhance Empathy and Decrease Prejudice

“…Meta-analyses of imaging studies have shown that autobiographical memory tasks recruit similar vmPFC areas to self-trait processing along with a number of other brain areas including the hippocampus (Spreng, Mar, & Kim, 2009;Svoboda, McKinnon, & Levine, 2006). Furthermore, a recent study examined functional connectivity between the hippocampus and neocortex during the retrieval and elaboration of episodic memories and found that while the dmPFC is functionally coupled to the hippocampus during the retrieval of memories the vmPFC strongly coupled to it both during retrieval and when participants are required to relive the memory in elaborate detail (McCormick, St-Laurent, Ty, Valiante, & McAndrews, 2015). These results further demonstrate the importance of the vmPFC to the processing and experience of the conceptual self.…”