Orbitofrontal Cortex Modulates Auditory Cortical Sensitivity and Sound Perception.

Sensory perception is dynamic, quickly adapting to sudden shifts in environmental or behavioral context. Though decades of work have established that these dynamics are mediated by rapid fluctuations in sensory cortical activity, we have a limited understanding of the brain regions and pathways that orchestrate these changes. Neurons in the orbitofrontal cortex (OFC) encode contextual information, and recent data suggest that some of these signals are transmitted to sensory cortices. Whether and how these signals shape sensory encoding and perceptual sensitivity remains uncertain. Here, we asked whether the OFC mediates context-dependent changes in auditory cortical sensitivity and sound perception by monitoring and manipulating OFC activity in freely moving animals under two behavioral contexts: passive sound exposure and engagement in an amplitude modulation (AM) detection task. We found that the majority of OFC neurons, including the specific subset that innervate the auditory cortex, were strongly modulated by task engagement. Pharmacological inactivation of the OFC prevented rapid context-dependent changes in auditory cortical firing, and significantly impaired behavioral AM detection. Our findings suggest that contextual information from the OFC mediates rapid plasticity in the auditory cortex and facilitates the perception of behaviorally relevant sounds. Significance Statement: Sensory perception depends on the context in which stimuli are presented. For example, perception is enhanced when stimuli are informative, such as when they are important to solve a task. Perceptual enhancements result from an increase in the sensitivity of sensory cortical neurons; however, we do not fully understand how such changes are initiated in the brain. Here, we tested the role of the orbitofrontal cortex (OFC) in controlling auditory cortical sensitivity and sound perception. We found that OFC neurons change their activity when animals perform a sound detection task. Inactivating OFC impairs sound detection and prevents task-dependent increases in auditory cortical sensitivity. Our findings suggest that the OFC controls contextual modulations of the auditory cortex and sound perception.