Brain imaging of chill reactions to pleasant and unpleasant sounds

The term 'chill' refers to a short-term bodily event of high arousal, which marks an emotional peak experience when occurring in response to music. Chill responses arise in a clearly circumscribed time frame and can also be reliably elicited by unpleasant sounds. Previous research, however, mostly focused on individually selected stimuli and positive contexts, thus, limiting the scope of interpretation. Hence, we developed a standardized chill paradigm and used fMRI to test neural responses of 16 healthy volunteers to pleasant and unpleasant emotional sound material while collecting subjective reports of chill intensity and skin conductance response data. As predicted, we found chill-associated increases in autonomic arousal regardless of the valence of the sound material. Apart from activity in primary and higher auditory cortices, both pleasant and unpleasant chills were associated with anterior insula, thalamus and basal ganglia activity. In contrast, amygdala responses were observed only in association with chills elicited by unpleasant sounds. Thus, chills elicited by pleasant and unpleasant sounds share activity in a neural network that may be specifically involved in the arousal component of an emotional experience.