2011 Theses Doctoral

Neural Mechanisms of Social Evaluative Threat

Spicer, Julie

Though the scientific study of stress is relatively new, not even one hundred years old, there has been robust inquiry and discovery in stress research since its instantiation. Yet, many unanswered questions remain on how specific stressors impact the mind, brain and body. Social threat is a pervasive form of stress for species that are organized in social hierarchies, like humans and some animals. Social evaluative threat (SET), occurring when there is potential for negative evaluation or rejection from others, is a pervasive and important form of stress in humans having many links to stress-related physiological outcomes which in turn have important implications for health outcomes. The brain is a critical component in the mind-brain-body-health connection, but less is known about SET at the neural level.
Here in this thesis, there are three studies that characterize the neural circuitry that responds to SET. Using a novel imaging technique, arterial spin labeling, Study 1 asks whether SET-related brain circuitry is modulated by a SET-related trait level vulnerability, Fear of Negative Evaluation (FNE). Overall, Study 1 replicated previous work by showing SET-related reactivity in the left pregenual anterior cingulate cortex, right ventromedial prefrontal cortex (vMPFC) and medial periaqueductal gray and extended previous work by showing that changes in the left vMPFC and the right thalamus were predicted by FNE. Using blood oxygenation level-dependent imaging (BOLD), Study 2 asks whether SET influences the brain circuitry on which the formation of relational episodic memory relies. With the use of mediation analysis, it was found that SET impaired relational episodic memory, and that the impairment was a function of activity in the right parahippocampal cortex and bilateral vMPFC. Using BOLD imaging, Study 3 asks whether SET influences the brain circuitry that subserves working memory (WM). With the use of mediation analysis, it was found that SET impaired WM, and that the impairment was a function of activity in bilateral intraparietal sulcus. Links between mind, brain, body and health are discussed throughout this work.