Intra-Individual Variability in Vagal Control Is Associated With Response Inhibition Under Stress

Abstract

Dynamic intra-individual variability (IIV) in cardiac vagal control across multiple situations is believed to contribute to adaptive cognition under stress; however, a dearth of research has empirically tested this notion. To this end, we examined 25 U.S. Army Soldiers (all male, mean age = 30.73, standard deviation (SD) = 7.71) whose high-frequency heart rate variability (HF-HRV) was measured during a resting baseline and during three conditions of a shooting task (training, low stress, high stress). Response inhibition was measured as the correct rejection (CR) of friendly targets during the low and high stress conditions. We tested the association between the SD of HF-HRV across all four task conditions (IIV in vagal control) and changes in response inhibition between low and high stress. Greater differences in vagal control between conditions (larger IIV) were associated with higher tonic vagal control during rest, and stronger stress-related decreases in response inhibition. These results suggest that flexibility in vagal control is supported by tonic vagal control, but this flexibility also uniquely relates to adaptive cognition under stress. Findings are consistent with neurobehavioral and dynamical systems theories of vagal function.

Vagal Flexibility Mediates the Association Between Resting Vagal Activity and Cognitive Performance Stability Across Varying Socioemotional Demands

“…It should be mentioned that, like the previous study (Spangler et al, 2018a), HRV metrics in the current study were associated with stability in cognitive inhibition (e.g., Stroop interference), specifically. The specificity of findings to inhibition is consistent with prior work that has strongly linked vagal activity to inhibitory control (i.e., Stroop interference, down-regulation of negative emotion).…”

“…The adaptive organism is able to adopt a pattern of stability or flexibility that best fits the situation (Miller and Cohen, 2001;Armbruster et al, 2012). Expanding on the prior study (Spangler et al, 2018a), present findings are consistent with vagal activity supporting patterns of cognition (flexibility vs. stability) that are most appropriate or adaptive for the situation (Thayer and Lane, 2009;Thayer et al, 2012). In the prior study (Spangler et al, 2018a), higher vagal flexibility was associated with less stability in response inhibition performance, which we interpreted to be an adaptive response.…”

“…Importantly, the present study operationalized vagal flexibility and performance stability with IIV in HRV and performance across different contexts, thereby capturing theoretically emphasized dynamics in vagal activity and cognition that most studies have ignored. The present study expanded on our prior study (Spangler et al, 2018a) in three ways. First, rather than examine adaptive instability in performance due to painful stimuli, we examined adaptive stability in performance amid innocuous motivational distractors.…”

“…Pearson correlation coefficients tested associations among RMSSD metrics (resting lnRMSSD, Reactivity MEAN , lnReactivity SD ), as well as the relations between these RMSSD metrics and interference measures (Interference MEAN , Interference SD ; Spangler et al, 2018a ). We re-ran the RMSSD–interference correlations as partial Pearson correlations coefficients (PCCs) that adjusted for sex, age, body mass index (BMI), and respiration rate (as proxied by HF-peak) – variables that potentially confound relations involving HRV ( Grossman et al, 1991 ; Reardon and Malik, 1996 ; Molfino et al, 2009 ; Koenig and Thayer, 2016 ).…”

“…Only one study has investigated a dynamic individual difference metric of vagal flexibility alongside performance stability across changing tasks (Spangler et al, 2018a). Here, individuals with higher vagal flexibility across multiple conditions (rest, recovery, shooting conditions) exhibited: (i) higher resting HRV and (ii) less stability in response inhibition performance -stronger increases in friendly fire from low to high threat (vibration to shock) in a shoot/no-shoot task.…”