The early development of the autonomic nervous system provides a neural platform for social behaviour: a polyvagal perspective

TLDR

The model highlights two sequential phases of neurophysiological development during the transition from fetus to newborn: myelinated vagal system maturation in the last trimester and cortical regulation of brainstem vagal areas during the first year postpartum. The study introduces a biobehavioral model linking heart vagal regulation measures to infant self‑regulation and social engagement. The model posits that newborns first use primitive brainstem‑visceral circuits for physiological regulation, then cortical control of the brainstem develops within the first year, shifting regulation from feeding to reciprocal social behavior.

Abstract

We present a biobehavioral model that explains the neurobiological mechanisms through which measures of vagal regulation of the heart (e.g., respiratory sinus arrhythmia) are related to infant self-regulatory and social engagement skills. The model describes the sequential development of the neural structures that provide a newborn infant with the ability to regulate physiological state in response to a dynamically changing postpartum environment. Initially, the newborn uses primitive brainstem-visceral circuits via ingestive behaviors as the primary mechanism to regulate physiological state. However, as cortical regulation of the brainstem improves during the first year of life, reciprocal social behavior displaces feeding as the primary regulator of physiological state. The model emphasizes two sequential phases in neurophysiological development as the fetus transitions to postpartum biological and social challenges: 1) the development of the myelinated vagal system during the last trimester, and 2) the development of cortical regulation of the brainstem areas regulating the vagus during the first year postpartum.