Interparental Conflict and Neural Functioning in Infancy: An fMRI Study
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Early life stress (ELS) affects the developing brain and impacts capacity for self-regulation and risk for psychopathology. The high spatial resolution of functional magnetic resonance imaging (fMRI) confers an advantage for studying specific neural regions posited to link ELS with subsequent functioning. The first chapter in this dissertation reviews the literature establishing the feasibility and utility of fMRI research with infants and young children. This chapter examines methodological issues and outlines the potential for this technique to make unique contributions to understanding how ELS influences brain development. The next two chapters present results from a study that employed a functional activation paradigm and resting state functional connectivity MRI (rs-fcMRI) to examine associations between a common source of ELS, non-physical interparental conflict, and neural functioning during infancy. The functional activation paradigm focused on emotional tone of voice as a stimulus relevant to interparental conflict, which is likely salient to infants. Higher levels of interparental conflict (as reported by mothers) were associated with infants (6 to 12 months of age) showing greater reactivity to very angry versus neutral tone of voice in neural regions associated with processing and regulation of stress and emotion (hypothalamus and rostral anterior cingulate cortex). The rs-fcMRI analysis examined coordinated neural functioning in the absence of stimuli, focusing on the amygdala as a key region for understanding the impact of ELS and the posterior cingulate cortex as part of a group of regions that show higher levels of activity in the absence of stimuli (the default network). The results replicate previous work characterizing the default network in infants and provide novel evidence for the functional connectivity of the amydgala and amygdala subregions during infancy. Interparental conflict was associated with variation in the connectivity of both regions. Thus levels of interparental conflict were associated with neural reactivity to a stressor-relevant stimulus and with patterns of coordinated neural functioning in the absence of such stimuli. These results provide support for the utility of using fMRI with infants to examine early emerging associations between common forms of ELS and brain functioning. This dissertation includes previously published and co-authored material.