Poster F82, Tuesday, March 28, 8:00 – 10:00 am, Pacific Concourse
Dynamic functional connectivity of overt and covert autobiographical memory retrieval
Charles Ferris1, Cory Inman1, Andrew James2, Stephan Hamann1; 1Emory University, 2University of Arkansas for Medical Sciences
Retrieval of autobiographical memories (AM) is a complex process that recruits dynamically changing networks of brain regions as processing shifts between memory search, access, and content elaboration. In prior fMRI work we have used graph analyses to characterize whole-brain changes in dynamic connectivity during AM retrieval, highlighting time-varying engagement of the hippocampus, PFC, and other regions. Here we used high temporal and spatial resolution fMRI, an optimized experimental design, and both covert and overt (spoken) retrieval to test theoretical accounts of dynamic AM retrieval processes. Motion minimization and post-processing was used to minimize speech artifact effects. During scanning, healthy adults retrieved unrehearsed AMs to cue words across an extended retrieval period, followed by ratings of vividness and emotion, with overt (spoken) retrieval during half of the runs. We identified regions active during different retrieval periods and used functional connectivity and graph theory analyses to examine dynamic changes in AM retrieval processes. Early, access-related processing activations were observed in the hippocampus, amygdala, mPFC, and PCC. Network connectivity changed substantially across AM retrieval, particularly for hippocampal-neocortical interactions. We observed dynamic changes in functional connectivity between the hippocampal region and fronto-parietal regions including the VLPFC and IPL. These results suggest that accessing and reconstructing autobiographical memories involves large-scale changes in functional connectivity that reflect the dynamic time-course of AM retrieval processes.
Topic Area: LONG-TERM MEMORY: Episodic