Psychology Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/2801
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Item Understanding the Relevance of Extended Amygdala Reactivity to Dispositional Negativity(2021) Grogans, Shannon Elizabeth; Shackman, Alexander J; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Elevated dispositional negativity (DN; i.e., neuroticism/negative emotionality) is associated with a range of deleterious outcomes, including mental illness. Yet, DN’s neurobiology remains incompletely understood. Prior work suggests that DN reflects heightened threat-elicited reactivity in the extended amygdala (EAc), a circuit encompassing the central nucleus (Ce) and the bed nucleus of the stria terminalis (BST), and that this association may be intensified for uncertain threat. We utilized a multi-trait, multi-occasion DN composite and neuroimaging assays of threat anticipation and perception to demonstrate that individuals with elevated DN show heightened BST activation during threat anticipation. Analyses revealed that DN is uniquely predicted by BST reactivity to uncertain threat. DN was unrelated to Ce activation during threat anticipation or EAc activation during ‘threatening’-face presentation. Follow-up analyses revealed that the threat paradigms are not interchangeable probes of EAc function. These observations lay the foundation for future studies necessary to determine causation and improve interventions.Item Understanding the anxiolytic effects of alcohol on the central extended amygdala in humans(2017) Kaplan, Claire Marjorie; Shackman, Alexander J; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The anxiety-reducing properties of alcohol are thought to contribute to development of alcohol dependence, particularly among individuals with anxiety disorders. Remarkably little is known, however, about the neural circuitry underlying anxiolytic effects of alcohol in humans. In a sample of 72 healthy adults, we employed the novel MultiThreat Countdown (MTC) task to investigate the dose-dependent consequences of acute alcohol intoxication (BAL range: 0.061 - 0.145%) during anticipation of certain or uncertain threat, compared to placebo. Focal analyses of the central extended amygdala revealed significant activation during threat in the right, but not left, hemisphere for both the central nucleus [Ce] and bed nucleus of the stria terminalis [BST]. Increasing BALs were associated with decreasing activation in right BST and self-reported fear/anxiety levels during threat. This effect did not differ between certain and uncertain threat. These results build upon converging lines of evidence and suggest involvement of BST in alcohol-induced anxiolysis.