(PS11-77) Gastric Myoelectrical Associations with Autonomic and Central Nervous System Activity During State Negative Emotionality and Perseverative Negative Thinking: A Two-study Investigation

Distress is known to set off a variety of physiological dysfunctions. There have been previous investigations of central and peripheral (e.g., cardiac) correlates of distress and a burgeoning field examining immunological and inflammatory relationships to distress. However, despite a connection between gastrointestinal symptoms and distress at the clinical level, little research has connected this activity to other biological correlates of distress. Heightened negative emotions and perseverative negative thinking (PNT, e.g., worry, rumination) are two components that underlie distress. Investigating the effect that these components have on gastric and related biological measures is crucial to better understanding the relationship between distress and health outcomes. We present results from two studies, which examined the impact of experimentally induced negative emotionality and PNT on gastric, autonomic nervous system, central nervous system, and inflammatory processes. In Study 1 (N = 95), we examined changes in electrogastrogram (EGG), respiratory sinus arrythmia (RSA), and alpha- and beta-band electroencephalogram (EEG) power at baseline and during experimental inductions of fear and sadness in a diverse sample of undergraduate students. In Study 2 (N = 30), we examined changes in EGG, RSA, and EEG at baseline and during worry and rumination inductions. We also collected inflammatory markers post-inductions in Study 2. In Study 1, multilevel modeling (MLM) was used as a framework for exploring change in EGG, RSA, and EEG from baseline to inductions as well as covariation between EGG, RSA, and EEG at baseline and during induction periods. We found that normal gastric activity (ds = -2.37 to -1.19), vagal tone (ds = -.97 to -.79), and alpha-power (ds = -.99 to -.64) decreased, whereas EGG cycle length (ds = .90 to 2.25) and EGG variability (ds = .70 to 1.73) increased during fear and sadness compared to baseline. We also observed significant relationships among EGG, RSA, and EEG during fear (e.g., negative covariation between RSA and normogastria) and sadness (e.g., negative covariation between normogastria and frontal alpha-band power). In Study 2, paired samples t-tests with Cohen’s d effect sizes were used to assess change in EGG, RSA, and EEG whereas bias-corrected and accelerated (BCa) bootstrapping with effect size estimation was used to explore relationships between biological variables at baseline and during the PNT inductions. Normal gastric activity (d = -1.07) and RSA (d = .93) decreased, whereas EGG cycle length (d = -.85) increased during rumination compared to baseline. Regarding relationships among EGG, RSA, EEG, and inflammation, greater EGG cycle variability was associated with higher vagal tone during worry (r = .65, p = .03); additionally, EGG cycle length (r = .60, p = .03) and EGG variability (r = .69, p = .01) during rumination were positively related to CRP and TNF-α inflammation composite scores post-inductions. These findings offer insight into how negative emotionality and PNT might relate to gastric, ANS, CNS, and inflammatory processes.