One of the great frontiers of consciousness science is understanding how early consciousness arises in the development of the human infant. The reciprocal relationship between the default mode network and frontoparietal networks—the dorsal attention and executive control network—is thought to facilitate integration of information across the brain and its availability for a wide set of conscious mental operations. It remains unknown whether the brain mechanism of conscious awareness is instantiated in infants from birth. To address this gap, we investigated the development of the default mode and fronto-parietal networks, and of their reciprocal relationship in neonates. To understand the effect of early neonate age on these networks, we also assessed neonates born prematurely, or before term equivalent age. We used the Developing Human Connectome Project, a unique Open Science dataset which provides a large sample of neonatal functional MRI data with high temporal and spatial resolution. Resting state functional MRI data for full-term neonates (N = 282, age 41.2 weeks ± 12 days), and preterm neonates scanned at term-equivalent age (N = 73, 40.9 weeks ± 14.5 days), or before term-equivalent age (N = 73, 34.6 weeks ± 13.4 days), were obtained from the Developing Human Connectome Project, and for a reference adult group (N = 176, 22–36 years), from the Human Connectome Project. For the first time, we show that the reciprocal relationship between the default mode and dorsal attention network was present at full-term birth or term-equivalent age. Although different from the adult networks, the default mode, dorsal attention, and executive control networks were present as distinct networks at full-term birth or term-equivalent age, but premature birth was associated with network disruption. By contrast, neonates before term-equivalent age showed dramatic underdevelopment of high-order networks. Only the dorsal attention network was present as a distinct network and the reciprocal network relationship was not yet formed. Our results suggest that, at full-term birth or by term-equivalent age, infants possess key features of the neural circuitry that enables integration of information across diverse sensory and high-order functional modules, giving rise to conscious awareness. Conversely, they suggest that this brain infrastructure is not present before infants reach term-equivalent age. These findings improve understanding of the ontogeny of high-order network dynamics that support conscious awareness, and of their disruption by premature birth.

One fundamental property of conscious experiences is that they are both differentiated and integrated. Adult functional brain networks exhibit an elegant "small-world" architecture. This optimal architecture enables efficient and cost-effective localized information processing and information integration between long-distance regions across the brain. It remains unclear whether the functional small-world architecture is developed in neonates at birth and how this development may be altered by premature birth. To address this gap, we investigated the development of small-world architecture in neonates. To understand the effect of early neonate age on small-world architecture, we also assessed neonates born prematurely or before term-equivalent age (TEA). We used the Developing Human Connectome Project (dHCP), a large neonatal functional magnetic resonance imaging (MRI) dataset with high temporal and spatial resolution. Resting state functional MRI data for full-term neonates (N = 278, age 41.2 weeks ± 12.2 days) and preterm neonates scanned at TEA (N = 72, 40.9 weeks ± 14.6 days), or before TEA (N = 70, 34.7 weeks ± 12.7 days), were obtained from the dHCP, and for a reference adult group (N = 176, 22 – 36 years), from the Human Connectome Project. Whole-brain functional network properties were evaluated with comprehensive spatial resolution using graph theoretical analyses. Although different from the adults', small-world architecture was developed in full-term born neonates at birth. Premature neonates before TEA showed dramatic underdevelopment of small-world architecture and regional communication in 9/11 brain networks, with disruption in 32% of nodes primarily distributed within the somatomotor, dorsal attention, cingulo-opercular, and frontoparietal control network. By TEA, premature neonates showed large-scale recuperation of regional communication, with 1.4% of nodes, distributed in the frontoparietal, salience, and visual networks remaining significantly underdeveloped. Our results suggest that, at full-term birth or by term-equivalent age, infants possess well-developed small-world architecture, which facilitates differentiated and integrated neural processes that give rise to conscious experiences. Conversely, they suggest that this brain infrastructure is significantly underdeveloped before infants reach term-equivalent age. These findings improve understanding of the ontogeny of functional small-world architecture and efficiency of neural communication across distinct brain networks in infants at birth.

One of the great frontiers of consciousness science is understanding how early consciousness arises in the development of the human infant. The reciprocal relationship between the default mode network (DMN) and frontoparietal networks — the dorsal attention network (DAN) and executive control network (ECN) — is thought to facilitate integration of information across the brain and its availability for conscious access to a wide set of mental operations. It remains unknown whether the brain mechanism of conscious awareness is instated in infants from birth. To address this gap, we asked what the impact of prematurity and neonate age is on the development the default mode and fronto-parietal networks, and of their reciprocal relationship. To address these questions, we used the Developing Human Connectome Project (dHCP), a unique Open Science project which provides a large sample of neonatal functional Magnetic Resonance Imaging (fMRI) data with high temporal and spatial resolution. Resting state fMRI data for full-term neonates (N = 282, age 41.2 w ± 12 d), and preterm neonates scanned at term-equivalent age (TEA) (N = 73, 40.9 w ± 14.5 d), or before TEA (N = 73, 34.6 w ± 13.4 d) were obtained from the dHCP, and for a reference adult group (N = 176, 22 – 36 years), from the Human Connectome Project. For the first time, we show that the reciprocal relationship between the DMN and DAN was present at full-term birth or TEA. Although different from the adult networks, the DMN, DAN and ECN were present as distinct networks at full-term birth or TEA, but premature birth disrupted network development. By contrast, neonates before TEA showed dramatic underdevelopment of high-order networks. Only the DAN was present as a distinct network and the reciprocal network relationship was not yet formed. Our results suggest that, at full-term birth or by term-equivalent age, infants possess key features of the neural circuitry that enables integration of information across diverse sensory and high-order functional modules, giving rise to conscious access. Conversely, they suggest that this brain infrastructure is not present before infants reach term-equivalent age. These findings improve understanding of the ontogeny of high-order network dynamics that support conscious awareness, and of their disruption by premature birth.