Individual Differences in Respiratory Sinus Arrhythmia and PhysiologicalEmotional Responses to Pictures

Respiratory sinus arrhythmia (RSA) is the modulation of heart rate along with respiration. Individual differences in RSA reflect parasympathetic cardiac control. Low RSA is linked to emotional dysregulation, perhaps from an inability to modulate the parasympathetic nervous system to emotion. For the current study, pictures of varying emotional contents were presented to participants with low and high RSA. During some pictures, acoustic probes were delivered to elicit startle. Emotional responding was assessed from subjective and physiological reactions to pictures. Results suggested that low RSA participants exhibited attenuated cardiac orienting compared to high RSA participants. Startle, corrugator electromyogram, and subjective responses to pictures were similar across groups. Thus, differences in RSA account for differences in orienting to emotional pictures but not physiological–emotional responding.