Olfactory input is critical for sustaining odor quality codes in human orbitofrontal cortex

Abstract

The olfactory system is vulnerable to sensory deprivation owing to the prevalence of rhinosinusitis, but how the brain encodes and maintains odor information under such circumstances remains poorly understood. Using fMRI, the authors find evidence for transient changes in olfactory brain regions that sustain odor perception following disrupted sensory input. Ongoing sensory input is critical for shaping internal representations of the external world. Conversely, a lack of sensory input can profoundly perturb the formation of these representations. The olfactory system is particularly vulnerable to sensory deprivation, owing to the widespread prevalence of allergic, viral and chronic rhinosinusitis, but how the brain encodes and maintains odor information under such circumstances remains poorly understood. Here we combined functional magnetic resonance imaging (fMRI) with multivariate (pattern-based) analyses and psychophysical approaches to show that a 7-d period of olfactory deprivation induces reversible changes in odor-evoked fMRI activity in piriform cortex and orbitofrontal cortex (OFC). Notably, multivoxel ensemble codes of odor quality in OFC became decorrelated after deprivation, and the magnitude of these changes predicted subsequent olfactory perceptual plasticity. Our findings suggest that transient changes in these key olfactory brain regions are instrumental in sustaining odor perception integrity in the wake of disrupted sensory input.