Resting-state networks in the infant brain

Abstract

In the absence of any overt task performance, it has been shown that spontaneous, intrinsic brain activity is expressed as systemwide, resting-state networks in the adult brain. However, the route to adult patterns of resting-state activity through neuronal development in the human brain is currently unknown. Therefore, we used functional MRI to map patterns of resting-state activity in infants during sleep. We found five unique resting-states networks in the infant brain that encompassed the primary visual cortex, bilateral sensorimotor areas, bilateral auditory cortex, a network including the precuneus area, lateral parietal cortex, and the cerebellum as well as an anterior network that incorporated the medial and dorsolateral prefrontal cortex. These results suggest that resting-state networks driven by spontaneous signal fluctuations are present already in the infant brain. The potential link between the emergence of behavior and patterns of resting-state activity in the infant brain is discussed.development ͉ functional MRI ͉ spontaneous activity R ecent research on functional connectivity in the brain, in particular during resting-state conditions, has come to focus on low-frequency (Ͻ0.1 Hz), spontaneous fluctuations in the functional MRI (fMRI) signal. Discovered by Biswal et al. (1), it has been shown that systemwide networks in the resting brain are synchronized in time through intrinsic low-frequency signal fluctuations. Whereas early fMRI studies demonstrated synchronicity of intrinsic brain activity across hemispheres in primary sensory cortices (2, 3), succeeding studies have shown temporal synchronization in a resting-state network encompassing higher-order cortices (4). A systematic investigation of resting-state activity in the adult human brain was recently presented by Damoiseaux et al. (5). Using independentcomponent analysis (ICA), a data-driven explorative data analysis approach, they showed that there are numerous networks in the brain that are driven by spontaneous activity. Besides networks that are in part or fully described by the previously reported default mode (6) and task-positive network (7, 8), they found consistent patterns of resting-state activity in the visual cortex, sensorimotor areas, auditory areas, as well as extrastriate brain regions. These findings together with previous investigations on spontaneous activity suggest that the assumption that the brain during rest is idle and waiting to be triggered and respond to changes in the environment is not strictly valid. Rather, in addition to responding to changes in external stimuli or tasks, the brain is characterized by intrinsic dynamics in the form of coherent and spontaneous fluctuations, clustered together in networks that are credible from an anatomical and functional perspective.Interestingly, recent studies have presented evidence that spontaneous activity is relevant for human behavior. Momentary lapses of attention, affecting goal-oriented behavior on a global/ local selective attention task, were related to a fai...

The emergence of functional architecture during early brain development

“…The first paper on the presence of functional brain networks in the neonatal brain was published in 2007 (Fransson et al, 2007) and a number of research groups have now committed to the challenging task of functional imaging in utero (Ferrazzi et al, 2014;Schöpf et al, 2012;Seshamani et al, 2014;Thomason et al, 2013). Collectively, these efforts have led to exciting insights into functional brain network architecture in the earliest phases following its emergence.…”

“…Historically, much of what we know about the intricate processes of early brain development came from post mortem studies in human fetuses, neonates, and non-human primates (Flechsig, 1920;Goldman-Rakic, 1987;Innocenti and Price, 2005;Kostovic, 2002;LaMantia and Rakic, 1990). With the increasing availability of high-quality neuroimaging techniques, including anatomical sequences customized to the developing neonatal and fetal brain, diffusion weighted imaging (DWI) and functional MRI, as well as electrophysiology recordings including electroencephalography (EEG), it has now become feasible to study early human brain development in unprecedented detail in vivo Counsell et al, 2007;Fransson et al, 2007;Huppi et al, 1998;Maas et al, 2004;Omidvarnia et al, 2014;Partridge et al, 2004;Smyser et al, 2001; Thomason et al, 2013;Toulmin et al, 2015;van den Heuvel et al, 2014). These advances have led to exciting new insights into both healthy and atypical macroscale brain network development and have paved the way to bridge the gap between the brain's neurobiological architecture and its behavioral repertoire.…”

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“…Fransson et al, in particular, examined the resting-state functional network architecture of very young preterm infants (25 weeks mean gestational age) and found that only half of the number of resting-state sub-networks found in healthy adults were present at the preterm stage [20]. Recently, van der Heuvel et al found that functional networks in preterm infants agreed well with the underlying anatomical structure [54].…”

Spontaneous brain activity observed with functional magnetic resonance imaging as a potential biomarker in neuropsychiatric disorders

“…These methods simultaneously decomposes group fMRI data into modes describing variations across space, time, and subjects. It has been demonstrated that these methods can provide useful representations of group fMRI data in resting-state studies (Damoiseaux et al 2006;Fransson et al 2007;Jafri et al 2008).…”