Neural and Navigational Features Influencing the Novelty Induced Benefits on Episodic Memory

Abstract

Studies in animals have robustly shown that exposure to novelty can promote memory for information presented in the temporal vicinity. In humans, however, evidence for such novelty-related memory benefits has been mixed. In this EEG study, we investigated the neurobiological mechanisms underlying effects of novelty on memory and whether individual differences in exploration patterns help explain these inconsistencies. We examined the role of theta oscillations in exploring a novel or familiar environment as well as whether spatial exploration behavior can modulate the beneficial effects of novelty on memory. Participants first explored one of two virtual environments and subsequently explored the same (familiar condition) or a new environment (novel condition). After exploring novel and familiar environments, participants performed a word learning task followed by a free recall and recognition memory test. Neurologically, exploration of the familiar rather than novel environment increased theta power, which may reflect environment-related memory processes. However, we did not observe any differences in theta power associated with successful encoding of words after exploring a novel versus familiar environment. Behaviorally, no main effect of novelty on free recall was observed. Crucially, when accounting for variance in spatial exploration patterns, words encoded after exploring a novel environment were recalled better than words encoded after exploring a familiar environment. Furthermore, an interaction effect between the condition and exploratory behavior revealed that increased exploration benefitted free recall specifically in the familiar condition. These findings emphasize the importance of considering the way in which individuals explore a virtual environment when examining novelty effects on memory.