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In recent years, exploration of the developing brain has become a major focus for researchers and clinicians in an attempt to understand what allows children to acquire amazing and unique abilities, as well as the impact of early disruptions (eg, prematurity, neonatal insults) that can lead to a wide range of neurodevelopmental disorders. Noninvasive neuroimaging methods such as MRI are essential to establish links between the brain and behavioral changes in newborns and infants. In this review article, we aim to highlight recent and representative studies using the various techniques available: anatomical MRI, quantitative MRI (relaxometry, diffusion MRI), multiparametric approaches, and functional MRI. Today, protocols use 1.5 or 3T MRI scanners, and specialized methodologies have been put in place for data acquisition and processing to address the methodological challenges specific to this population, such as sensitivity to motion. MR sequences must be adapted to the brains of newborns and infants to obtain relevant good soft-tissue contrast, given the small size of the cerebral structures and the incomplete maturation of tissues. The use of age-specific image postprocessing tools is also essential, as signal and contrast differ from the adult brain. Appropriate methodologies then make it possible to explore multiple neurodevelopmental mechanisms in a precise way, and assess changes with age or differences between groups of subjects, particularly through large-scale projects. Although MRI measurements only indirectly reflect the complex series of dynamic processes observed throughout development at the molecular and cellular levels, this technique can provide information on brain morphology, structural connectivity, microstructural properties of gray and white matter, and on the functional architecture. Finally, MRI measures related to clinical, behavioral, and electrophysiological markers have a key role to play from a diagnostic and prognostic perspective in the implementation of early interventions to avoid long-term disabilities in children. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY STAGE: 1.

It is now clearly established that the environment and the sensory stimuli, particularly during the perinatal period, have an impact on infant's development. During the last trimester of gestation, activity-dependent plasticity shapes the fetal brain, and prematurity has been shown to alter the typical developmental trajectories. In this delicate period, preventive interventions aiming at modulating these developmental trajectories through activity-inducing interventions are currently underway to be tested. The purpose of this review paper is to describe the potentialities of early vocal contact and music on the preterm infant's brain development, and their potential beneficial effect on early development. Scientific evidence supports a behavioral orientation of the newborn to organized sounds, such as those of voice and music, and recent neuroimaging studies further confirm full cerebral processing of music as multisensory stimuli. However, the impact of long-term effects of music exposure and early vocal contact on preterm infants' long-term neurodevelopment needs be further investigated. To conclude, it is necessary to establish the neuroscientific bases of the early perception and the long-term effects of music and early vocal contact on the premature newborns' development. Scientific projects are currently on the way to fill this gap in knowledge.

L'amélioration des soins périnataux a augmenté le taux de survie des nouveau-nés prématurés. L'environnement a un impact sur le développement sensorimoteur et le comportement de l'enfant durant la période néonatale. Le concept des soins de développement est une approche multidisciplinaire et individualisée intégrant les parents, premiers partenaires des soins. Cette prise en charge préventive soutient un développement harmonieux de ces enfants vulnérables.

Fetal growth restriction (FGR) is a significant complication of pregnancy describing a fetus that does not grow to full potential due to pathological compromise. FGR affects 3-9% of pregnancies in high-income countries, and is a leading cause of perinatal mortality and morbidity. Placental insufficiency is the principal cause of FGR, resulting in chronic fetal hypoxia. This hypoxia induces a fetal adaptive response of cardiac output redistribution to favour vital organs, including the brain, and is in consequence called brain sparing. Despite this, it is now apparent that brain sparing does not ensure normal brain development in growth-restricted fetuses. In this review we have brought together available evidence from human and experimental animal studies to describe the complex changes in brain structure and function that occur as a consequence of FGR. In both humans and animals, neurodevelopmental outcomes are influenced by the timing of the onset of FGR, the severity of FGR, and gestational age at delivery. FGR is broadly associated with reduced total brain volume and altered cortical volume and structure, decreased total number of cells and myelination deficits. Brain connectivity is also impaired, evidenced by neuronal migration deficits, reduced dendritic processes, and less efficient networks with decreased long-range connections. Subsequent to these structural alterations, short- and long-term functional consequences have been described in school children who had FGR, most commonly including problems in motor skills, cognition, memory and neuropsychological dysfunctions.

Due to advances in neonatal intensive care over the last decades, the pattern of brain injury seen in very preterm infants has evolved in more subtle lesions that are still essential to diagnose in regard to neurodevelopmental outcome. While cranial ultrasound is still used at the bedside, magnetic resonance imaging (MRI) is becoming increasingly used in this population for the assessment of brain maturation and white and grey matter lesions. Therefore, MRI provides a better prognostic value for the neurodevelopmental outcome of these preterms. Furthermore, the development of new MRI techniques, such as diffusion tensor imaging, resting state functional connectivity and magnetic resonance spectroscopy, may further increase the prognostic value, helping to counsel parents and allocate early intervention services.

Magnetic resonance imaging (MRI) is a safe and high-resolution neuroimaging modality that is increasingly used in the neonatal population to assess brain injury and its consequences on brain development. It is superior to cranial ultrasound for the definition of patterns of both white and gray matter maturation and injury and therefore has the potential to provide prognostic information on the neurodevelopmental outcomes of the preterm population. Furthermore, the development of sophisticated MRI strategies, including diffusion tensor imaging, resting state functional connectivity, and magnetic resonance spectroscopy, may increase the prognostic value, helping to guide parental counseling and allocate early intervention services.

Studying how the brain develops and becomes functional is important to understand how the man has been able to develop specific cognitive abilities, and to comprehend the complexity of some developmental pathologies. Thanks to magnetic resonance imaging (MRI), it is now possible to image the baby's immature brain and to consider subtle correlations between the brain anatomical development and the early acquisition of cognitive functions. Dedicated methodologies for image acquisition and post-treatment must then be used because the size of cerebral structures and the image contrast are very different in comparison with the adult brain, and because the examination length is a major constraint. Two recent studies have evaluated the developing brain under an original perspective. The first one has focused on cortical folding in preterm newborns, from 6 to 8 months of gestational age, assessed with T2-weighted conventional MRI. The second study has mapped the organization and maturation of white matter fiber bundles in 1- to 4-month-old healthy infants with diffusion tensor imaging (DTI). Both studies have enabled to highlight spatio-temporal differences in the brain regions' maturation, as well as early anatomical asymmetries between cerebral hemispheres. These studies emphasize the potential of MRI to evaluate brain development compared with the infant's psychomotor acquisitions after birth.

Developmental care is a multidisciplinary approach aiming at improving the premature newborn's well-being through individualized observation and care, and at limiting environmental nociceptive stimuli. The aim is to lessen neonatal morbidity and enhance long-term psychomotor development in this population of high-risk newborns.

Preterm children born before 32 weeks of gestation represent 1% of the annual births in Switzerland, and are the most at risk of neurodevelopmental disabilities. A neurological surveillance is thus implemented in the neonatal units, and multidisciplinary neurodevelopmental follow-up is offered to all our preterm patients. The follow-up clinics of the University hospitals in Lausanne and Geneva follow the Swiss guidelines for follow-up. An extended history and neurological examination is taken at each appointment, and a standardized test of development is performed. These examinations, which take place between the ages of 3 months and 9 years old, allow the early identification and treatment of developmental disorders frequent in this population, such as motor, cognitive or behavioral disorders, as well as the monitoring of the quality of neonatal care.

Understanding human brain development from the fetal life to adulthood is of great clinical importance as many neurological and neurobehavioral disorders have their origin in early structural and functional cerebral maturation. The developing brain is particularly prone to being affected by endogenous and exogenous events through the fetal and early postnatal life. The concept of 'developmental plasticity or disruption of the developmental program' summarizes these events. Increases in white matter, which speed up communication between brain cells, growing complexity of neuronal networks suggested by gray and white matter changes, and environmentally sensitive plasticity are all essential aspects in a child's ability to mentalize and maintain the adaptive flexibility necessary for achieving high sociocognitive functioning. Advancement in neuroimaging has opened up new ways for examining the developing human brain in vivo, the study of the effects of early antenatal, perinatal and neonatal events on later structural and functional brain development resulting in developmental disabilities or developmental resilience. In this review, methods of quantitative assessment of human brain development, such as 3D-MRI with image segmentation, diffusion tensor imaging to assess connectivity and functional MRI to visualize brain function will be presented.

Evidence exists that the developing organism adapts to the environment it finds itself. Short and long-term adjustments take place and will initially induce intrauterine growth retardation but will also have consequences that will appear later in life. These adjustments are referred as "programming". The use of advanced magnetic resonance imaging techniques in IUGR babies has delineated changes in the development of the central nervous system that correlate with altered neurodevelopment and could be implicated in the development of neuropsychiatric disorders in adult life. In this review, we will delineate some modifications of CNS development and functions that occur after exposition to adverse environment and that can now be studied in vivo with advanced imaging technology.

There are now a number of evidences showing that the developing organism adapts to the environment it finds itself. Short- and long-term adjustments, referred as "programming", take place and will initially induce intrauterine growth retardation but will also have consequences that will appear later in life. The use of magnetic resonance imaging (MRI) techniques in IUGR babies has delineated changes in the central nervous system (CNS) development that correlate with altered neurodevelopment and could be implicated in the development of neuropsychiatric disorders in adult life. Similarly, the use of corticosteroid treatment in preterm infants has also been implicated in abnormal CNS development. In this review, we will focus on the modifications of CNS development that occur after exposition to adverse environment such as undernutrition or corticosteroid treatment that can now be studied in vivo with advanced MRI technology.

Understanding early human brain development is of great clinical importance, as many neurological and neurobehavioral disorders have their origin in early structural and functional cerebral organization and maturation. Diffusion tensor imaging (DTI), a recent magnetic resonance (MR) modality which assesses water diffusion in biological tissues at a microstructural level, has revealed a powerful technique to explore the structural basis of normal brain development. In fact, the tissue organization can be probed non-invasively, and the age-related changes of diffusion parameters (mean diffusivity, anisotropy) reveal crucial maturational processes, such as white matter myelination. Nevertheless, the developing human brain presents several challenges for DTI applications compared with the adult brain. DTI may further be used to detect brain injury well before conventional MRI, as water diffusion changes are an early indicator of cellular injury. This is particularly critical in infants in the context of administration of neuroprotective therapies. Changes in diffusion characteristics further provide early evidence of both focal and diffuse white matter injury in association with periventricular leukomalacia in the preterm infant. Finally, with the development of 3D fiber tractography, the maturation of white matter connectivity can be followed throughout infant development into adulthood with the potential to study correlations between abnormalities on DTI and ultimate neurologic/cognitive outcome.

In order to provide accurate prognosis and developmental intervention to newborns, new methods of assessing cerebral functions are needed. The non-invasive technique of functional magnetic resonance imaging (fMRI) can be considered as the leading technique for functional exploration of the infant's brain. Several studies have previously applied fMRI in both healthy and diseased newborns with different sensory and cognitive tasks. In this chapter, the methodological issues that are proper to the use of fMRI in the newborn are detailed. In addition, an overview of the major findings of previous fMRI studies is provided, with a focus on notable differences from those in adult subjects. More specifically, the functional responses and the localization of cortical activations in healthy and diseased newborns are discussed. We expect a rapid expansion of this field and the establishment of fMRI as a valid clinical diagnostic tool in the newborn.

To investigate the effects of early experience on brain function and structure.

The human brain is susceptible to a wide variety of insults. The permanent residua of these abnormalities are represented in dysfunction of one or more areas of neurodevelopment. A full understanding of normal brain development, mechanisms of brain injury, and consequences for subsequent brain development is required to determine which infants are at risk for neurodevelopmental handicap, and to monitor the effects of new treatments and management regimens designed to prevent these disabilities. Advanced magnetic resonance techniques, such as quantitative morphometric magnetic resonance techniques, diffusion-weighted magnetic resonance techniques, and magnetic resonance spectroscopy applied to the study of early human brain development have given us a better understanding of the pathophysiologic mechanisms of brain injury and its effects on subsequent brain development. Magnetic resonance imaging has provided an invaluable tool for the study of the fetal and newborn brain in vivo.

The application of diffusion tensor imaging (DTI) to the evaluation of developing brain remains an area of active investigation. This review focuses on the changes in DTI parameters which accompany both brain maturation and injury. The two primary pieces of information available from DTI studies-water apparent diffusion coefficient and diffusion anisotropy measures-change dramatically during development, reflecting underlying changes in tissue water content and cytoarchitecture. DTI parameters also change in response to brain injury. In this context, not only does DTI offer the possibility of detecting injury earlier than conventional imaging methods, but also appears more sensitive to disruption of white matter than any other imaging method. DTI offers unique insight into brain injury and maturation, and does so in a fashion that can be readily applied in a clinical setting.

Magnetic resonance (MR) techniques are attractive for use in the developing brain because of their resolving power and their relative noninvasiveness. Their ability to provide detailed structural as well as metabolic and functional information without the use of ionizing radiation is unique. Conventional MR Imaging has widely proven its potential for identifying normal and pathologic brain morphology. Functional MR imaging such as diffusion-weighted imaging (DWI) and perfusion and blood-oxygenation-dependent BOLD imaging are newer imaging methods providing insights into brain physiology. This review will focus on the application of different MR techniques including the conventional structural MR imaging techniques and the more advanced MR techniques, such as the quantitative morphometric MR methods, the diffusion weighted MR techniques, the functional MR techniques and MR spectroscopy in the study of the fetal and newborn brain.

Despite marked improvements in perinatal practice, perinatal brain injury remains one of the most common complications causing chronic handicapping conditions. Experimental advances have elucidated many of the cellular and vascular mechanisms of perinatal brain damage showing a correlation between the nature of the injury and the maturation of the brain. New diagnostic tools, such as quantitative three-dimensional magnetic resonance (MR) imaging, diffusion-weighted MR imaging and proton MR spectroscopy, are presented in this review article that allow to assess brain development, detect early brain injury and monitor effects of perinatal brain injury on subsequent brain development and brain plasticity. These techniques will guide future therapeutic interventions aimed at minimizing irreversible perinatal brain injury.

MR imaging provides an invaluable tool for the study of brain development in vivo. Current MR imaging techniques allow noninvasive methodologies, without ionizing radiation, that provide a diversity of information on structure, metabolism, and function of the developing brain. This article focuses on the application of conventional and advanced MR imaging techniques, including quantitative morphometric MR imaging, diffusion-weighted, functional MR, and MR spectroscopic imaging to the study of early human brain development.

Understanding of the morphological development of the human brain has largely come from neuropathological studies obtained postmortem. Magnetic resonance (MR) techniques have recently allowed the provision of detailed structural, metabolic, and functional information in vivo on the human brain. These techniques have been utilized in studies from premature infants to adults and have provided invaluable data on the sequence of normal human brain development. This article will focus on MR techniques including conventional structural MR imaging techniques, quantitative morphometric MR techniques, diffusion weighted MR techniques, and MR spectroscopy. In order to understand the potential applications and limitations of MR techniques, relevant physical and biological principles for each of the MR techniques are first reviewed. This is followed by a review of the understanding of the sequence of normal brain development utilizing these techniques. MRDD Research Reviews 6:59-67, 2000.

We report the case of a 27-week premature infant in whom magnetic resonance imaging (MRI) at 4 postnatal weeks (postconceptional age, 31 weeks), term, and 6 months of age documented the postnatal postmigrational evolution of bilateral perisylvian polymicrogyria. The polymicrogyria was readily detected by ultrafine 1.5-mm coronal slices on three-dimensional, Fourier-transformed, spoiled gradient-recalled and T2-weighted MRI sequences. These MRI sequences provide the first in vivo documentation of the postmigrational evolution of polymicrogyria. The likelihood that the polymicrogyria was related to an ischemic encephaloclastic mechanism is supported by the simultaneous occurrence of periventricular leukomalacia.

La naissance prématurée expose les enfants à des stimuli nocifs pendant une période critique de maturation cérébrale, entraînant des conséquences néfastes sur leur neurodéveloppement. La musicothérapie a été proposé comme intervention précoce visant à enrichir l'apport sensoriel des prématurés pendant cette période de plasticité et ainsi améliorer la maturation cérébrale. En s'appuyant sur l'IRM de diffusion, cette thèse a évalué les effets d'une intervention musicale sur le développent structurel cérébral des enfants très prématurés. Les résultats démontrent que d'importantes modifications de la microstructure e de l'organisation du cerveau du prématuré ont lieu entre la 33ème semaine de gestation jusqu'à l'âge équivalent du terme (TEA), lesquelles sont affectées par la naissance prématurée. L'intervention musicale postnatale précoce a conduit à une maturation microstructurelle significativement supérieure de plusieurs fibres de la substance blanche, ainsi que de diverses régions corticales impliquées dans le traitement des émotions et la cognition, en particulier le circuit orbitofrontal-temporopolaire.