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Browsing by Author "Nackley, Brittany B."

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    Only time will tell: Acute stress response patterns with time series analysis
    Nackley, Brittany B.; Friedman, Bruce H. (Elsevier, 2021-05-12)
    Stress has long attracted attention in psychophysiological research, due to its effects on physiology that are measurable and well documented. Acute stress is often conceptualized as a response pattern that activates the fight-or-flight response via the sympathetic nervous system (SNS). However, other stress response patterns can manifest as well, such as parasympathetic nervous system (PNS) shutdown, and SNS-PNS coactive hypervigilance. Each response pattern engages many dimensions, including physiological, emotional, and behavioral. Additionally, as stress unfolds over time, these patterns can change to adjust to the changing nature of the stressor. This proof of concept study introduces novel methodology to track the patterns and multidimensional manifestations of stress. Virtual reality (VR) was used to induce a dynamic range of stress responses. The defense cascade provides a model with which to understand and predict response patterns over the time course of an acute stressor.
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    Temporal Dynamics of the Defense Cascade
    Nackley, Brittany B. (Virginia Tech, 2020)
    Understanding physiological responses to threat can inform therapeutic interventions for phobias, anxieties, and PTSD. The defense cascade is reviewed as a theoretical model that predicts behavioral and physiological responses to threats. Nineteen undergraduates (five male), average age 19.4 experienced a novel virtual reality (VR) threat scenario while their physiology was measured. The Subjective Units of Distress Scale (SUDS) was used as a self-report indicator of distress in the research setting. Averaged SUDS reports suggested that the VR stimulus was experienced as threatening for most participants, but their autonomic response patterns did not fit those predicted by the defense cascade. Participants who had scored high on adaptive response questionnaires tended to show uncoupled ANS activation during baseline, but varied across the stimulus condition. Nearly all participants showed either coactivation or reciprocal activation during the stimulus period except those reporting the most dissociative trauma experiences, who mostly showed uncoupled ANS activation.