Distinct and coordinated contributions of hippocampus and frontal eye field to novelty exploration and revisitation

Humans dynamically alternate between exploring novel information and revisiting familiar content, yet the neural mechanisms that separately govern these behaviors remain incompletely understood. In this study, we combined intracranial electrophysiology with eye-tracking to investigate the respective roles of the hippocampus (HP) and frontal eye field (FEF) at the level of individual fixations during a visual working memory task. During novelty exploration, hippocampal high-theta activity increased before fixation onset, suggesting a role in anticipatory attention, while FEF theta oscillations were enhanced following fixation, consistent with sustained attention that facilitated novelty processing. During revisitation, HP might drive gaze through low-theta-gamma phase-amplitude coupling associate with potential memory retrieval process, and subsequently enhanced low-theta oscillations related to potential memory consolidation. Stronger theta-phase synchrony between the FEF and HP was also observed during this revisitation process. Together, these findings reveal distinct yet coordinated FEF-HP dynamics that underpin attention-driven exploration and memory-guided revisitation, providing new electrophysiological evidence for the interaction between attention and memory. Our findings may help inform future research on targeted interventions for attention or memory impairment.