Chronic Early Stress Impairs Default Mode Network Connectivity in Preadolescents and Their Mothers.

BACKGROUND: Early life stress (ELS) bears long-term negative consequences throughout life. Yet ELS effect is mostly unknown, and no study has followed children to test its impact on the default mode network (DMN) in relation to maternal behavior across childhood. Focusing on brain oscillations, we utilized a unique cohort of war-exposed preadolescent children (11-13 years of age) and their mothers followed from early childhood to examine the effects of ELS combined with observed parenting on DMN connectivity and power in mother and child.

METHODS: Participants included 161 mothers and children (children: 39 exposed/36 control subjects; mothers: 44 exposed/42 control subjects) who underwent magnetoencephalography scanning during rest.

RESULTS: Stress exposure reduced DMN connectivity in mother and child; however, in mothers, the impaired connectivity occurred in the alpha band, whereas among children it occurred in the theta band, a biomarker of the developing brain. Maternal anxiety, depression, and posttraumatic symptoms in early childhood predicted lower maternal DMN connectivity. Among children, the experience of intrusive, anxious, and uncontained parenting across the first decade and greater cortisol production in late childhood predicted reduced DMN connectivity in preadolescence. Impairments to theta DMN connectivity increased in children with posttraumatic stress disorder.

CONCLUSIONS: Findings indicate that ELS disrupts the synchronous coordination of distinct brain areas into coherent functioning of the DMN network, a core network implicated in self-relevant processes. Results suggest that one pathway for the lifelong effects of ELS on psychopathology and physical illness relate to impaired coherence of the DMN and its role in maintaining quiescence, alternating internal and external attention, and supporting the sense of self.