This is the first fMRI study to characterize the neurobiological profile of emotional arousal and reactivity in sensation seeking. Previous research has shown that HSSs, compared with LSSs, show greater reactivity to intense stimuli (Smith et al., 1990; Zuckerman, 2005) and weaker avoidance responses to stressors (Lissek et al., 2005; Roberti, 2004). Such outcomes may be understood within a framework in which HSSs tend to have overactive approach systems and dampened avoidance systems (A. Lang et al., 2005). The present findings are consistent with this framework in that fMRI responses to high-arousal stimuli were stronger in HSSs than in LSSs in brain regions associated with arousal and reinforcement, including the insula and posterior medial OFC. In contrast, HSSs did not activate regions involved in emotional regulation, behavioral monitoring, and decision making (e.g., anterior cingulate and anterior medial OFC) as strongly or as early as LSSs did. Moreover, HSSs were not as sensitive to the valence of the stimuli as were LSSs. The propensity for arousal in HSSs may override the valence or content of the arousing material. These differences between
