Over the past century, research has helped us build a fundamental understanding of the neurobiological underpinnings of anxiety. Specifically, anxiety engages a broad range of cortico-subcortical neural circuitry. Core to this is a ‘defensive response network’ which includes an amygdala-prefrontal circuit that is hypothesized to drive attentional amplification of threat-relevant stimuli in the environment. In order to help prepare the body for defensive behaviors to threat, anxiety also engages peripheral physiological systems. However, our theoretical frameworks of the neurobiology of anxiety are built mostly on the foundations of tightly-controlled experiments, such as task-based fMRI. Whether these findings generalize to more naturalistic settings is unknown. To address this shortcoming, movie-watching paradigms offer an effective tool at the intersection of tightly controlled and entirely naturalistic experiments. Particularly, using suspenseful movies presents a novel and effective means to induce and study anxiety. In this thesis, I demonstrate the potential of movie-watching paradigms in the study of how trait and state anxiety impact the ‘defensive response network’ in the brain, as well as peripheral physiology. The key findings reveal that trait anxiety is associated with differing amygdala-prefrontal responses to suspenseful movies; specific trait anxiety symptoms are linked to altered states of anxiety during suspenseful movies; and states of anxiety during movies impact brain-body communication. Notably, my results frequently diverged from those of conventional task-based experiments. Taken together, the insights gathered from this thesis underscore the utility of movie-watching paradigms for a more nuanced understanding of how anxiety impacts the brain and peripheral physiology. These outcomes provide compelling evidence that further integration of naturalistic methods will be beneficial in the study of the neurobiology of anxiety
