Autonomic Mechanisms of Emotional Reactivity and Regulation

Abstract

The ability to perceive and regulate our emotions appropriately is essential for social behavior. Our subjective emotional states to changing external cues are accompanied by physiological changes in heart rate variability (HRV), which is regulated by the sympathetic and parasympathetic branches of the autonomic nervous systems (ANS). In this pilot study, we sought to elucidate the autonomic basis of emotional reactivity and regulation in response to ecologically-valid emotional stimuli—presented in the form of filmclips—in healthy subjects. Subjects watched a series of videos, validated to elicit feelings of amusement, sexual amusement, sadness, fear, and disgust. Subjects were also asked to regulate the outward expression of their response to disgust by suppressing or amplifying it when instructed. Electrodes placed on the torso measured cardiac and respiratory signals, which were processed to compute HRV, which when analyzed with the concurrent respiratory signal calculates measures of parasympathetic activity (RFA, Respiratory Frequency Area, from higher frequencies) and sympathetic activity (LFA, Low Frequency Area, from lower frequencies). Fluctuations in LFA and RFA were computed by the coefficient of variation, and the intensity of the emotional response to the film-clips was captured via questionnaires. Our results suggest that in healthy individuals, higher intensities of subjective emotional experience, both positive (e.g., amusement) and negative (e.g., amplified disgust) elicit higher LFA (sympathetic) responses, whereas emotional regulation is mediated primarily by fluctuations in RFA (parasympathetic) activity. Furthermore, correlations between emotional intensity and components of HRV suggest that higher positive or lower negative emotional states may increase the capacity for emotional regulation via modulation of the parasympathetic component. Our results suggest that a sense of humor might facilitate emotional control.