Emotion perception through the nose: How olfactory emotional cues modulate the perception of neutral facial expressions in affective disorders

Abstract

Abstract Human body odors are an effective modality of social communication. Individuals exposed to emotional body odors report a partial reproduction of the affective state of the sender. The present study aimed to explore how body odors collected in happiness and fearful conditions modulate the subjective ratings, the psychophysiological response and the neural processing of neutral faces in individuals with depressive symptoms, social anxiety symptoms, and healthy controls (N = 22 per group). To this aim, electrocardiogram (ECG) and HD-EEG were recorded continuously. For subjective ratings, individuals with depressive symptoms rated the neutral faces as more arousing when presented with the fear odor compared to the clean air condition. The heart rate variability (HRV) results showed a main effect of odor: HRV increased during the fear and happiness body odors compared to clean air, suggesting that at a peripheral level the two emotional body odors seem to increase the vagal tone. Lastly, event-related potentials (ERPs) and event-related spectral perturbations (ERPSs) extracted from the EEG were analysed. For ERPs data, mixed ANOVA analyses did not show any significant effects. However, the ERPSs analyses revealed that the emotional body odors modulated the processing of the neutral faces both at an early and a late stage of stimulus processing, regardless of the presence of depressive or social anxiety symptoms. The current research offers new insights, demonstrating that emotional chemosignals serve as potent environmental cues. This represents a substantial advancement in comprehending the impact of emotional chemosignals in both individuals with and without affective disorders.