THE SENSORY-MOTOR PATHWAY FOR NOVELTY-EVOKED ORIENTING

Exploration of novel stimuli is a fundamental behavior observed across virtually all animal species. In mice, novel stimuli reliably evoke orienting behaviors such as exploratory sniffing. Novelty detection typically occurs at the earliest stages of sensory processing. In the case of olfaction, even at the level of the olfactory bulb, individual neurons are not only tuned to particular odorants but also show heightened responses to novel stimuli. Much less is known about how novelty is processed at later stages of sensory processing. A strong candidate for studying this process is the orbitofrontal cortex (OFC), a multisensory region involved in decision-making and salience processing, making it well positioned to influence exploratory behavior. This raises the question of how the OFC processes novel sensory stimuli and whether it contributes causally to novelty‑evoked orienting responses.
To investigate this, we examined OFC function using a passive odor‑exposure paradigm. We found that the OFC neurons which are typically odor‑selective, also respond more strongly to initial presentations of an odor, and display heterogeneous tuning across odorants. Thus, information about odor identity and odor novelty is mixed within the OFC. Optogenetic stimulation of long‑range OFC projections was sufficient to evoke exploratory sniffing, a hallmark orienting behavior in rodents.
Together, these findings indicate that the OFC plays a key role in processing novel olfactory cues and contributes to the generation of orienting behaviors. More broadly, they support a role for the OFC in curiosity‑driven exploration across multiple sensory modalities.