Poster #23 - Examining Interactions Between Stress Physiology Systems at Rest and Executive Functions Among Low-Income Children

• In Event: 1-005 - Poster Session 01
  In Poster Session: PS 01 Section - Biological Processes: Psychophysiology

Integrative Statement

INTRODUCTION
Extensive research has demonstrated that stress response physiology and cognitive processes, such as executive functions (EF), operate in a reciprocally dependent manner (Arnsten, 2009; Blair & Ursache, 2012; Obradovic and Broyce, 2012). In particular, the two main physiological stress response systems—the autonomic nervous system (ANS) and the hypothalamic-pituitary-adrenal (HPA) axis—have been found to modulate EF. Further, previous studies have shown that, environments of early-life adversity, such as poverty, are linked both to stress response systems and to EF outcomes (Blair et al.,2013; Blair et al., 2011). Most relevant studies examining relations between stress physiology and EF have focused on either the ANS or HPA system independently. However, the interactions between both stress response systems and their associations to EF in early childhood not often been examined, especially in contexts of risk, despite the functional interdependence of the ANS and HPA axis. Thus, this study employed a multisystem approach to further elucidate the interactions between basal ANS and HPA axis activity and their relations to EF in early childhood.

METHODS
Data from this study come from the Family Life Project (Vernon-Feagans, Cox, & Investigators, 2013), a large prospective longitudinal sample (N=1,292) of children and their caregivers from predominantly low-income, rural communities in Pennsylvania and North Carolina. At 48 months of age, children participated in a battery of EF tasks assessing working memory, inhibitory control, and attention switching. Prior to the EF tasks, saliva samples were collected and assayed for cortisol and alpha amylase (AA), and electrocardiography was recorded to measure respiratory sinus arrhythmia (RSA) and inter-beat interval (IBI). Baseline levels of cortisol, RSA, IBI, and AA were collected to assess resting stress physiology of the HPA and ANS systems, respectively.

RESULTS
Regression analyses were conducted to assess associations among variables. As shown in Table 1, results indicate that baseline IBI positively predicted EF at 48 months such that increases in IBI (i.e., decreases in heart rate) related to better EF performance (β = 0.123, SE = 0.047, p < 0.05). Conversely, baseline RSA negatively predicted EF such that increases in RSA related to lower EF (β = -0.118, SE = 0.048, p < 0.05). There were no associations between baseline cortisol or AA and EF. However, there was an interaction between baseline cortisol and baseline IBI such that higher cortisol negatively predicted EF, but only for children who also had higher baseline IBI (β = -.075, SE = .032, p < 0.05) (see Figure 1). This interaction indicates that IBI activity buffers the negative effects of cortisol on EF. Importantly, these effects were observed while controlling for an earlier measure of EF, parenting behavior, and demographic covariates, including age, gender, and race/ethnicity.

CONCLUSION
These findings suggest that baseline or resting stress physiology can serve as a salient predictor of EF in childhood. Additionally, these results elucidate how basal ANS and HPA axis activity differentially and interactively relate to children’s EF, and point to possible mechanisms of risk and resilience in contexts of adversity that warrant further investigation.

Authors

• Krystalle Lyons, Stony Brook University
  Presenting Author

• Kevon Williams, California State Polytechnic University, Pomona
  Non-Presenting Author

• Sashana Rowe-Harriott, Hunter College CUNY
  Non-Presenting Author

• Stephen H. Braren, New York University
  Non-Presenting Author

• Annie Brandes-Aitken, Department of Applied Psychology, New York University
  Non-Presenting Author

• Clancy Blair, New York University
  Non-Presenting Author