Anticipation of novel environments enhances memory for incidental information

Curiosity-driven exploration: foundations in neuroscience and computational modeling

Curiosity refers to the intrinsic desire of humans and animals to explore the unknown, even when there is no apparent reason to do so. Thus far, no single, widely accepted definition or framework for curiosity has emerged, but there is growing consensus that curious behavior is not goal-directed but related to seeking or reacting to information. In this review, we take a phenomenological approach and group behavioral and neurophysiological studies which meet these criteria into three categories according to the type of information seeking observed. We then review recent computational models of curiosity from the field of machine learning and discuss how they enable integrating different types of information seeking into one theoretical framework. Combinations of behavioral and neurophysiological studies along with computational modeling will be instrumental in demystifying the notion of curiosity.

Differential effects of expectancy on memory formation in young and older adults

Novelty can promote subsequent long-term memory via the mesolimbic system, including the medial temporal lobe and midbrain structures. Importantly, these and other brain regions typically degenerate during healthy aging, which suggests a reduced impact of novelty on learning. However, evidence in favor of such a hypothesis is scarce. Thus, we used functional MRI in combination with an established paradigm in healthy young (19-32 years, n = 30) and older (51-81 years, n = 32) humans. During encoding, colored cues predicted the subsequent presentation of either a novel or previously familiarized image (75% cue validity), and approximately 24 h later, recognition memory for novel images was tested. Behaviorally, expected novel images, as compared to unexpected novel images, were better recognized in young and, to a lesser degree, older subjects. At the neural level, familiar cues activated memory related areas, especially the medial temporal lobe, whereas novelty cues activated the angular gyrus and inferior parietal lobe, which may reflect enhanced attentional processing. During outcome processing, expected novel images activated the medial temporal lobe, angular gyrus and inferior parietal lobe. Importantly, a similar activation pattern was observed for subsequently recognized novel items, which helps to explain the behavioral effect of novelty on long-term memory. Finally, age-effects were pronounced for successfully recognized novel images with relatively stronger activations in attention-related brain regions in older adults; younger adults, on the other hand, showed stronger hippocampal activation. Together, expectancy promotes memory formation for novel items via neural activity in medial temporal lobe structures and this effect appears to be reduced with age.

Novelty processing associated with neural beta oscillations improves recognition memory in young and older adults

Novelty anticipation activates the mesolimbic system and promotes subsequent long-term memory in younger adults. Importantly, mesolimbic structures typically degenerate with age, which might reduce positive effects of novelty anticipation. Here, we used electroencephalography in combination with an established paradigm in healthy young (19-33 years old, n = 28) and older (53-84, n = 27) humans. Colored cues predicted the subsequent presentation of either a novel or previously familiarized image (75% cue validity). On the subsequent day, recognition memory for the novel images was tested. Behaviorally, novelty anticipation improved recollection-based but not familiarity-based recognition memory in both groups, and this effect was more pronounced in older subjects. Furthermore, novelty and familiarity cues increased theta (4-8 Hz) and decreased alpha/beta power (9-20 Hz); at outcome, expected novel and familiar images both increased beta power (13-25 Hz). Finally, a subsequent memory effect for expected novel images was associated with increases in beta power independent of age. Together, novelty anticipation drives hippocampus-dependent long-term recognition memory across the life span, and this effect appears to be related to neural beta oscillations.