Aversive Learning Enhances Perceptual and Cortical Discrimination of Indiscriminable Odor Cues

TLDR

Learning to associate sensory cues with threats is critical for minimizing aversive experience, and the ecological benefit of associative learning depends on accurate perception of predictive cues, yet how aversive learning enhances perceptual acuity of sensory signals, especially in humans, remains unclear. The study investigates how aversive learning improves perceptual acuity of sensory signals in humans. Using multivariate fMRI and olfactory psychophysics, the authors showed that initially indistinguishable odor enantiomers become discriminable after aversive conditioning, mirroring divergent ensemble activity patterns in primary olfactory cortex. Aversive learning induces piriform plasticity, enabling discrimination of previously indistinguishable odor enantiomers and transforming indiscriminable sensations into discriminable percepts, thereby enhancing sensory cue perception and supporting adaptive behavior.

Abstract

Learning to associate sensory cues with threats is critical for minimizing aversive experience. The ecological benefit of associative learning relies on accurate perception of predictive cues, but how aversive learning enhances perceptual acuity of sensory signals, particularly in humans, is unclear. We combined multivariate functional magnetic resonance imaging with olfactory psychophysics to show that initially indistinguishable odor enantiomers (mirror-image molecules) become discriminable after aversive conditioning, paralleling the spatial divergence of ensemble activity patterns in primary olfactory (piriform) cortex. Our findings indicate that aversive learning induces piriform plasticity with corresponding gains in odor enantiomer discrimination, underscoring the capacity of fear conditioning to update perceptual representation of predictive cues, over and above its well-recognized role in the acquisition of conditioned responses. That completely indiscriminable sensations can be transformed into discriminable percepts further accentuates the potency of associative learning to enhance sensory cue perception and support adaptive behavior.