Abstract
AbstractDynamic interactions between large-scale brain networks underpin human cognitive processes, but their electrophysiological mechanisms remain elusive. The triple network model, encompassing the salience (SN), default mode (DMN), and frontoparietal (FPN) networks, provides a framework for understanding these interactions. To unravel the electrophysiological mechanisms underlying these network interactions, we analyzed intracranial EEG recordings from 177 participants across four diverse episodic memory experiments, each involving encoding as well as recall phases. Phase transfer entropy analysis revealed consistently higher directed information flow from the anterior insula, a key SN node, to both DMN and FPN nodes. This causal influence was significantly stronger during memory tasks compared to resting-state, highlighting the anterior insula’s task-specific role in coordinating large-scale network interactions. This pattern persisted across externally-driven memory encoding and internally-governed free recall. We also observed task-specific suppression of high-gamma power in the posterior cingulate cortex/precuneus node of the DMN during memory encoding, but not recall. Crucially, these results were robustly replicated across all four experiments spanning verbal and spatial memory domains with high Bayes replication factors. These findings significantly advance our understanding of how coordinated neural network interactions support memory processes. They highlight the anterior insula’s critical role in orchestrating large-scale brain network dynamics during both memory encoding and retrieval. By elucidating the electrophysiological basis of triple network interactions in episodic memory, our results provide insights into neural circuit dynamics underlying memory function and offer a framework for investigating network disruptions in neurological and psychiatric disorders affecting memory.
Publisher
Cold Spring Harbor Laboratory