Neural subnetwork signatures distinguishing source and item memory retrieval: A meta-analysis of 66 fMRI studies

This meta-analysis of 66 functional magnetic resonance imaging (fMRI) studies investigated neural subnetworks underlying source versus item memory retrieval, emphasizing functional distinctions within major intrinsic brain networks. Results revealed clear differences in subnetwork activation patterns between the two retrieval types. Within the Frontoparietal Network, Subnetwork A exhibited stronger activation during source retrieval, highlighting its key role in managing cognitive control processes necessary for complex memory tasks; in contrast, Subnetworks B and C showed minimal or no task-specific engagement. Conversely, within the Default Mode Network, Subnetworks A and B were selectively activated during item memory retrieval, suggesting their contribution to the increased subjective vividness characteristic of simpler recollective experiences, while Subnetwork C remained inactive across both retrieval conditions. Lastly, within the Ventral Attention Network, Subnetwork B-but not Subnetwork A-was more active during source than item memory retrieval, possibly reflecting its specific role in coordinating neural activity under the heightened demands of complex retrieval. Together, these findings advance understanding of subnetwork-specific roles in episodic memory retrieval and highlight the utility of subnetwork-level analyses for uncovering detailed functional specialization within large-scale brain networks.