Watching the fetal brain at ‘rest’

Functional magnetic resonance imaging (fMRI) has allowed insights into the spatiotemporal distribution of human brain networks. According to the neurophysiological property of the fetal brain to generate spontaneous activity, we aimed to determine the feasibility of investigating the maturation of intrinsic networks, beginning at gestational week 20 in healthy human fetuses by combining resting-state fMRI and an analytical approach, independent component analysis (ICA).In this study, functional images of 16 fetuses with morphologically normal brain development, from 20 to 36 gestational weeks of age, were acquired on a 1.5 T unit (Philips Medical Systems, Best, The Netherlands) using single-shot, gradient-recalled echo-planar imaging. After preprocessing (motion correction, brain extraction), images were analyzed using single-subject ICA.We visualized a bilateral occipital network and medial and lateral prefrontal activity pattern that involved the future Brodmann areas 9–11. Furthermore, there was one either predominantly right (3/7 cases) or left (4/7 cases) hemispheric lateralized network that involved the superior temporal cortical regions (Brodmann areas 22 and 39). Frequency oscillations were in the range of 0.01–0.06 Hz for all networks.This study shows that resting-state networks (RSNs) are shaped and are detectable in utero. Further investigations of resting-state measurements in the fetus may therefore allow developmental brain activity monitoring and may provide insights into early brain function.

► This study shows that resting-state networks (RSNs) are shaped and are detectable in utero.
► Three networks were observed across gestational weeks 20–36: a bilateral frontal; a bilateral occipital; and a unilateral temporal component.
► Fetal resting-state MRI is an appropriate and promising tool with which to study and map spontaneous fetal brain activity.