Maturation of default mode network functional connectivity strength in utero and the association with subcortical macrostructure: mapping brain ontogeny supporting early cognitive processing
Abstract
The third trimester of gestation is scarcely studied despite this being a key window for the development of learning and memory systems. In a prospective cohort study, 30 pregnant women participated in one or two fetal MR imaging sessions between 28- and 39 weeks of gestational age. Activation time courses were extracted from the default mode (DMN), medial temporal lobe (MTL), and thalamocortical (TCN) networks of the fetal brain. Generalized estimating equations were used to examine the association between the DMN-MTL, DMN-TCV connectivity strength, and subcortical volumes. Increased functional connectivity strength between the DMN-MTL networks was negatively associated with smaller hippocampal volumes. In contrast, increased functional connectivity strength in DMN-TCN was associated with smaller thalamic volumes. No associations between DMN connectivity strength were seen with cerebellar volumes. These associations indicate the emergence of strong short-range connectivity in the third trimester. Developing fetal MRI biomarkers facilitates the formation of a normative model of brain networks involved in cognitive processes.