Poster F114, Tuesday, March 28, 8:00 – 10:00 am, Pacific Concourse
Neural coding of odor “liking” and “wanting” in the olfactory sensory hierarchy
Sarah Baisley1, Thomas Campbell Arnold1, Jaryd Hiser2, Lucas Novak1, Takuya Sato3, Wen Li1; 1Florida State University, 2University of Wisconsin-Madison, 3Kikkoman Singapore R&D Laboratory PTE LTD
The “liking” and “wanting” reward components are an increasingly popular research area, yet it is unclear how the human olfactory system contributes to the encoding of odor valence (liking) and reward incentive (wanting). This study examines neural representations of odor incentive and valence in the olfactory cortical hierarchy, including the anterior/posterior piriform cortex (APC/PPC), orbitofrontal cortex (OFC), and amygdala. Participants (N=27) categorized odors (isointense, merely detectable) from three categories (food/floral/wood) while viewing a picture congruent or incongruent to the odor. Food odors were high in reward incentive and positive valence; floral odors were high in positive valence only; and wood odors were low in both properties. Support vector machine (SVM) analysis and representational similarity analysis (RSA) were performed on functional magnetic resonance imaging (fMRI) data. SVM analysis misclassified floral odor more often as food than wood in the APC, PPC, and amygdala (P’s<0.05) but not OFC, regardless of visual-olfactory congruency, suggesting that low- to intermediate-level olfactory regions are more likely to encode valence than incentive value. RSA results showed greater representational similarity between floral and wood odors in PPC than between floral and food odors during congruent trials only (P<0.05), suggesting that visual input facilitates PPC incentive encoding. The amygdala showed greater representational similarity between floral and food odors, but only during incongruent trials (P<0.05), suggesting sensitivity to olfactory valence input. These results suggest that the olfactory sensory system contributes to odor valence “liking” encoding, while the PPC may also be involved in incentive “wanting” encoding of congruent visual-olfactory input.
Topic Area: PERCEPTION & ACTION: Multisensory