Coupled Oscillator Models Reveal Novel Self- and Co-Regulatory Parasympathetic Dynamics in Infancy

• In Event: Novel Approaches to Examining Learning and Self-Regulation Development Across Context and Levels of Analysis

Abstract

Background
The parasympathetic nervous system operates both within individuals and in response to the social world to support regulatory processes (Porges, 2018). Existing research suggests a complex interplay between nascent self- and co-regulatory dynamics in infancy (Feldman, 2015) with open questions about their continuous unfolding. Despite developmentalists’ longstanding theoretical commitments to dynamic systems accounts of infant-caregiver processes, our methodological approaches often fail to capture these dynamics directly. The present study uses dynamic systems models to quantify the oscillatory patterns of mother and infant parasympathetic activity, including multiple novel forms of self- and co-regulatory dynamics simultaneously (Helm et al., 2012).

Current Study
44 mothers and their infants (M=9 mo) completed a modified ‘Still-Face’ task (face-to-face, text message perturbation, recovery). Electrocardiography was collected from mothers and infants and individual respiratory sinus arrhythmia (RSA) was quantified offline at each 1-second as an indicator of parasympathetic activity. First and second derivatives were quantified using functional data analysis before a coupled damped linear oscillator model (Figure 1B; Boker & Laurenceau, 2006) was fit to mother and infant RSA to quantify individual self- (η, ζ) and co- (γ1, γ2) regulatory dynamics (Table 1).

Hypotheses
We hypothesized self-regulatory dynamics: individual RSA activity would exhibit oscillatory dynamics (η<0), increasing and decreasing around a baseline with no individual damping or amplifying effects (ζ~0; Figure 1A), similar to other neurophysiological systems. We further hypothesized co-regulation: positive, bidirectional coupling to level (γ1>0) with open questions about damping/amplifying effects on each other’s signals (γ2).

Results
For self-regulatory dynamics, results indicate that on average, mother and infant RSA exhibited oscillatory patterns (ηinfant= -0.017, p<0.001; ηmother=-0.018, p<0.001; Figure 1C). There was no evidence of individuals damping or amplifying of their own oscillations, on average (ζinfant= -0.0020, p=0.50; ζmother =-0.0016, p=0.55). For co-regulatory dynamics, results indicate that mothers and infants were not coupled with respect to one another’s RSA level (γ1infant->mother=0.00013, p=0.71; γ1mother->infant=0.0031, p=0.66). However, they were coupled with respect to acceleration, exhibiting putative damping (γ2infant->mother = -0.0065, p=0.018; Figure 1Aii) and amplifying (γ2mother->infant=0.0068, p=0.014; Figure 1Ai) effects on each other’s oscillations.

Conclusions
Findings are consistent with the conceptualization that parasympathetic dynamics function like a pendulum, oscillating around a set point. Our results indicate that, similar to adults, infant nascent parasympathetic regulatory systems constitute a dynamic system with oscillatory patterns: they increase and decrease before returning back toward baseline with an overshoot. Interacting mothers and infants also constitute a coupled dynamic system. When mothers augment parasympathetic activity, their infant’s oscillations amplify (i.e., infant parasympathetic activity deviates more from baseline). Conversely, when infants augment parasympathetic activity, their mother’s oscillations dampen (i.e., mothers’ parasympathetic activity returns to baseline more quickly). These results suggest a nuanced co-regulatory dynamic in infancy: when caregivers are more regulated, their infant occupies a wider range of parasympathetic states relative to baseline, perhaps exercising more of their own intrinsic regulatory capacities. Findings suggest that co-regulation takes the form of modulating individual oscillatory ranges and offer novel insight into the real-time interplay between self- and co-regulatory dynamics of the parasympathetic nervous system in infancy.

Authors

• Isabella Chask'a Stallworthy, University of Minnesota - Twin Cities
  Presenting Author

• Jed T. Elison, University of Minnesota - Twin Cities

• Daniel Berry, University of Minnesota - Twin Cities