Disentangling the Effects of Novelty, Valence and Trait Anxiety in the Bed Nucleus of the Stria Terminalis, Amygdala and Hippocampus with High Resolution 7T fMRI

The hippocampus and amygdala exhibit novelty-sensitivity that is reduced in participants with inhibited temperament, which is related to trait anxiety. Although the bed nucleus of the stria terminalis (BST) is highly connected to the amygdala and is implicated in anxiety, whether the BST responds to novelty remains unstudied, as well as how trait anxiety may modulate this response. Additionally how novelty, stimulus negativity and trait anxiety interact to affect activity in these areas is also unclear. To address these questions, we presented participants with novel and repeated, fearful and neutral faces, while measuring brain activity via fMRI, and also assessed participants’ self-reported trait anxiety. As the small size of the BST makes assessing its activity at typical fMRI resolution difficult, we employed high resolution 7 Tesla scanning. Our results replicate findings of novelty-sensitivity that is independent of valence in the hippocampus and amygdala. We also found left amygdala sensitivity to stimulus negativity that was blunted for high trait anxiety participants. Our results also provide novel evidence for a BST novelty response toward neutral, but not fearful faces. We also found that the novelty responses exhibited by each of these ROIs was blunted in participants with high trait anxiety. These findings extend past research on the response to novel stimuli in the hippocampus and amygdala at high resolution, and are the first to demonstrate trait anxiety modulated novelty-sensitivity in the BST that is dependent on stimulus valence.