Congratulations to Shannon Grogans, who successfully defended her (pre-registered) Master’s thesis, entitled “Understanding the Relevance of Extended Amygdala Reactivity to Dispositional Negativity.”

As Shannon notes in the thesis, dispositional negativity—the propensity to experience and express more intense, frequent, or persistent negative affect—is a fundamental dimension of mammalian temperament. Elevated levels of dispositional negativity are associated with a wide range of practically important outcomes, from marital stability and socioeconomic attainment to anxiety disorders and depression. Yet our understanding of the brain bases of dispositional negativity remains far from complete. Converging lines of mechanistic and neuroimaging evidence suggest that dispositional negativity reflects heightened threat reactivity in the extended amygdala—a circuit encompassing the dorsal amygdala in the region of the central nucleus (Ce) and the neighboring bed nucleus of the stria terminalis (BST)—and that this association may be more evident when threat is uncertain.

To address this, Shannon used a combination of approaches—including a multi-trait, multi-occasion composite of dispositional negativity and neuroimaging assays of threat anticipation and perception—to demonstrate that individuals with a more negative disposition show heightened BST activation during threat anticipation. A series of cross-validated, robust regression analyses revealed that dispositional negativity is uniquely predicted by BST reactivity to uncertain-threat anticipation. In contrast, dispositional negativity was unrelated to amygdala activation during the anticipation of threat or to extended amygdala activation during the presentation of ‘threatening’ faces.

As Shannon notes, these brain imaging observations lay the foundation for the kinds of prospective-longitudinal and mechanistic studies that will be necessary to determine causation and, ultimately, to develop improved interventions for extreme dispositional negativity.