Emotional Responses to Pleasant and Unpleasant Oral Flavour Stimuli

The hedonic valence of taste perception plays a crucial role in the control of responses related to feeding behaviour. Taste and olfaction perception can induce autonomic responses, such as heart rate variability (HRV), which are involved in the evoked emotional reactions. Analysis of HRV can help distinguish sympathetic from parasympathetic regulation of the sinoatrial node. In this work, we analysed the HRV associated with oral flavour stimuli with opposite hedonic dimension and assessed their sympathovagal balance. ECGs were recorded continuously on 11 men and 12 women before and after stimulations. Experiments were performed in two sessions for comparison. ANOVA highlighted the decreases and increases of sinusal rhythm associated with pleasant and unpleasant flavour stimulations, respectively. Time and frequency domain analysis of HRV indicates that bradycardia induced by the pleasant stimulus can be attributed to an increase in the vagal tone, whilst tachycardia evoked by the unpleasant stimulus denotes a reduction of the vagal tone in women and an increase of the sympathetic tone in men. In conclusion, our data suggest that the HRV analysis may represent a valuable tool for autonomic nervous system response characterization associated to the hedonic dimension of the complex flavour sensations induced by food and/or beverages.