Neural dynamics of relational memory retrieval across eye movements
Relational memory retrieval involves a dynamic interplay between eye movements and neural activity, yet the timing of these processes remains unclear. This study investigates how theta and alpha EEG activity align with sequential fixations during relational memory retrieval. Participants performed a two-alternative forced-choice associative memory task while their eye movements and EEG were simultaneously recorded. Results reveal a relational eye-movement effect, with correctly remembered target elements disproportionately viewed during later fixations in the retrieval sequence. Time-frequency EEG analyses across the test interval show that successful retrieval was characterized by an early transient increase in theta power and a sustained decrease in alpha power. Fixation-related analyses linked these effects to specific retrieval processes: the theta increase emerged during the first fixation on the target following the cue, reflecting its role in pattern completion critical for retrieval. In contrast, the alpha decrease extended across subsequent fixations, suggesting a broader involvement in memory reactivation. These findings tie the relational eye-movement effect to distinct neural processes: an early theta increase associated with retrieving cue-target associations and a more gradual alpha decrease linked to memory reactivation across fixations. By uncovering the neural activity underpinning the relational eye-movement effect, this study provides novel insights into the temporal dynamics of relational memory retrieval and highlights the importance of sequential eye movements in shaping memory-guided behavior.