Lateralized Frontal-to-Temporal Cross-Frequency Coupling in Cortical Processing of Pleasant Odors

Olfactory perception recruits multiple neurocognitive processes, that are implemented across distributed but highly interactive brain areas housed primarily in the frontal and temporal lobes. Given that these brain areas have different functions and activity characteristics, the mechanisms supporting functional interactions between them are unclear. To address this knowledge gap, we analyzed EEG cross-frequency coupling (CFC) between frontal to left vs. right temporal regions during exposure to fragrances of varying subjective pleasantness. Our results show that higher-pleasantness fragrances gave rise to right-Iateralized θ - γ coupling and left-lateralized α - γ coupling, which likely represent memory processing and emotional processing respectively. Regression models reveal that fragrance pleasantness exhibits a linear relationship with θ - γ laterality, but a nonlinear relationship with α - γ laterality. These findings illustrate the significant role that CFCs play in long-distance neural communication in olfactory perception. Their robust dynamics in response to subjective odor evaluation render them as promising neural features for olfactory brain-computer interfacing.