Increased BNST Reactivity to Affective Images is Associated with Greater α-Amylase Response to Social Stress

While rodent research suggests that the bed nucleus of the stria terminalis (BNST) and centromedial amygdala (CM) coordinate the hormonal stress response, little is known about the BNST's role in the human stress response. The human BNST responds to negatively-valenced stimuli, which likely subserves its role in responding to threat. Thus, variation in BNST reactivity to negatively-valenced stimuli may relate to differences in the stress response. We measured participants' blood-oxygenated-level-dependent response to affective images, and salivary cortisol and alpha-amylase (AA) levels in response to a subsequent Trier Social Stress Test (TSST). Greater BNST activation to emotionally evocative images was associated with a larger TSST-evoked AA, but not cortisol response. This association remained after controlling for CM activation, which was not related to the cortisol or AA response. These results suggest that the BNST response to negatively-valenced images subserves its role in coordinating the stress response, a BNST role in the stress response independent from the CM, and highlight the need for investigation of the conditions under which BNST activation predicts the cortisol response. Our findings are critical for the future study of mood and anxiety disorders, as dysregulation of the stress system plays a key role in their pathogenesis.