A circuit-based mechanism underlying familiarity signaling and the preference for novelty.

The mechanistic basis of how novel stimuli become familiar with repeated exposures has remained elusive. Molas et al. demonstrate that familiarity activates the interpeduncular nucleus, thereby reducing motivation to explore. Familiarity signaling in the interpeduncular nucleus is bidirectionally modulated by habenula and ventral tegmental area afferents to control novelty preference.