Using the Actor-Partner Interdependence Model to assess maternal and infant contributions to mother-infant affective exchanges during the Still-Face Paradigm

This study describes maternal and infant contributions to dyadic affective exchanges during the Still-Face Paradigm (SFP) in an understudied mostly low-income sample. One hundred eleven mothers and their 7-month-old infants were videotaped during the SFP to analyze how a social stressor affects mother-infant positive and negative affective exchanges during interaction. The SFP includes 3 episodes: baseline, maternal still-face, and reunion. Maternal and infant positive and negative affect were scored by masked reliable coders. Data were analyzed using the Actor-Partner Interdependence Model to test the hypotheses that each partner's affectivity during the baseline episode would predict their own affectivity during the reunion episode (actor effects). We also expected that each partner's affectivity during the baseline episode would influence the other partner's affectivity during the reunion episodes (partner effects). After controlling for infant sex and maternal education, results provided evidence for actor effects for maternal and infant positive affect, and for partner effects for maternal baseline positive affect to infant positive affect during the reunion. One significant partner effect was observed for negative affect: Infant negativity during baseline predicted greater maternal negativity during reunion. Findings confirm that both mothers and infants contribute to dyadic affective processes during the SFP but specific findings vary depending on the affective valence in question. Clinical implications and future research are discussed.

Prenatal neural origins of infant motor development: Associations between fetal brain and infant motor development

Functional circuits of the human brain emerge and change dramatically over the second half of gestation. It is possible that variation in neural functional system connectivity in utero predicts individual differences in infant behavioral development, but this possibility has yet to be examined. The current study examines the association between fetal sensorimotor brain system functional connectivity and infant postnatal motor ability. Resting-state functional connectivity data was obtained in 96 healthy human fetuses during the second and third trimesters of pregnancy. Infant motor ability was measured 7 months after birth using the Bayley Scales of Infant Development. Increased connectivity between the emerging motor network and regions of the prefrontal cortex, temporal lobes, posterior cingulate, and supplementary motor regions was observed in infants that showed more mature motor functions. In addition, females demonstrated stronger fetal-brain to infant-behavior associations. These observations extend prior longitudinal research back into prenatal brain development and raise exciting new ideas about the advent of risk and the ontogeny of early sex differences.

Functional integrity in children with anoxic brain injury from drowning

Drowning is a leading cause of accidental injury and death in young children. Anoxic brain injury (ABI) is a common consequence of drowning and can cause severe neurological morbidity in survivors. Assessment of functional status and prognostication in drowning victims can be extremely challenging, both acutely and chronically. Structural neuroimaging modalities (CT and MRI) have been of limited clinical value. Here, we tested the utility of resting-state functional MRI (rs-fMRI) for assessing brain functional integrity in this population. Eleven children with chronic, spastic quadriplegia due to drowning-induced ABI were investigated. All were comatose immediately after the injury and gradually regained consciousness, but with varying ability to communicate their cognitive state. Eleven neurotypical children matched for age and gender formed the control group. Resting-state fMRI and co-registered T1-weighted anatomical MRI were acquired at night during drug-aided sleep. Network integrity was quantified by independent components analysis (ICA), at both group- and per-subject levels. Functional-status assessments based on in-home observations were provided by families and caregivers. Motor ICNs were grossly compromised in ABI patients both group-wise and individually, concordant with their prominent motor deficits. Striking preservations of perceptual and cognitive ICNs were observed, and the degree of network preservation correlated (ρ = 0.74) with the per-subject functional status assessments. Collectively, our findings indicate that rs-fMRI has promise for assessing brain functional integrity in ABI and, potentially, in other disorders. Furthermore, our observations suggest that the severe motor deficits observed in this population can mask relatively intact perceptual and cognitive capabilities. Hum Brain Mapp 38:4813-4831, 2017. © 2017 Wiley Periodicals, Inc.

White Matter Tract Pathology in Pediatric Anoxic Brain Injury from Drowning

BACKGROUND AND PURPOSE

Although drowning is a leading cause of mortality and morbidity in young children, the neuropathologic consequences have not been fully determined. The purpose of this article was to quantitatively characterize white matter microstructural abnormalities in pediatric anoxic brain injury from nonfatal drowning and investigate the correlation with motor function.

MATERIALS AND METHODS

Whole-brain T1-weighted and diffusion-weighted MR imaging datasets were acquired in 11 children with chronic anoxic brain injury and 11 age- and sex-matched neurotypical controls (4-12 years of age). A systematic evaluation form and scoring system were created to assess motor function. Tract-Based Spatial Statistics was used to quantify between-group alterations in the diffusion tensor imaging indices of fractional anisotropy and mean diffusivity and to correlate with per-subject functional motor scores.

RESULTS

Group-wise Tract-Based Spatial Statistics analyses demonstrated reduced fractional anisotropy in the bilateral posterior limbs of the internal capsule and the splenium of the corpus callosum (P < .001). Mean diffusivity was more diffusely increased, affecting the bilateral superior corona radiata, anterior and posterior limbs of the internal capsule, and external capsules (P < .001). Individual-subject fractional anisotropy and mean diffusivity values derived from the ROIs of the bilateral posterior limbs of the internal capsule strongly correlated with motor scores and demonstrated more potent between-group effects than with ROIs of the entire corticospinal tract.

CONCLUSIONS

These data particularly implicate the deep white matter, predominantly the posterior limbs of the internal capsule, as targets of damage in pediatric anoxic brain injury with drowning. The substantial involvement of motor-system tracts with relative sparing elsewhere is notable. These results localize white matter pathology and inform future diagnostic and prognostic markers.

Lenticulostriate arterial distribution pathology may underlie pediatric anoxic brain injury in drowning

Drowning is a leading cause of neurological morbidity and mortality in young children. Anoxic brain injury (ABI) can result from nonfatal drowning and typically entails substantial neurological impairment. The neuropathology of drowning-induced pediatric ABI is not well established. Specifically, quantitative characterization of the spatial extent and tissue distribution of anoxic damage in pediatric nonfatal drowning has not previously been reported but could clarify the underlying pathophysiological processes and inform clinical management. To this end, we used voxel-based morphometric (VBM) analyses to quantify the extent and spatial distribution of consistent, between-subject alterations in gray and white matter volume. Whole-brain, high-resolution T1-weighted MRI datasets were acquired in 11 children with chronic ABI and 11 age- and gender-matched neurotypical controls (4–12 years). Group-wise VBM analyses demonstrated predominantly central subcortical pathology in the ABI group in both gray matter (bilateral basal ganglia nuclei) and white matter (bilateral external and posterior internal capsules) (P < 0.001); minimal damage was found outside of these deep subcortical regions. These highly spatially convergent gray and white matter findings reflect the vascular distribution of perforating lenticulostriate arteries, an end-arterial watershed zone, and suggest that vascular distribution may be a more important determinant of tissue loss than oxygen metabolic rate in pediatric ABI. Further, these results inform future directions for diagnostic and therapeutic modalities.

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First quantitative characterization of anoxic brain injury in pediatric drowning

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Voxel-based morphometry revealed predominant central subcortical pathology.

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Lenticulostriate arterial distribution may underlie gray and white matter damage.

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Predominant damage of motor-system components observed.

Age-related increases in long-range connectivity in fetal functional neural connectivity networks in utero

Formation of operational neural networks is one of the most significant accomplishments of human fetal brain growth. Recent advances in functional magnetic resonance imaging (fMRI) have made it possible to obtain information about brain function during fetal development. Specifically, resting-state fMRI and novel signal covariation approaches have opened up a new avenue for non-invasive assessment of neural functional connectivity (FC) before birth. Early studies in this area have unearthed new insights about principles of prenatal brain function. However, very little is known about the emergence and maturation of neural networks during fetal life. Here, we obtained cross-sectional rs-fMRI data from 39 fetuses between 24 and 38 weeks postconceptual age to examine patterns of connectivity across ten neural FC networks. We identified primitive forms of motor, visual, default mode, thalamic, and temporal networks in the human fetal brain. We discovered the first evidence of increased long-range, cerebral-cerebellar, cortical-subcortical, and intra-hemispheric FC with advancing fetal age. Continued aggregation of data about fundamental neural connectivity systems in utero is essential to establishing principles of connectomics at the beginning of human life. Normative data provides a vital context against which to compare instances of abnormal neurobiological development.

Intrinsic connectivity network mapping in young children during natural sleep

Structural and functional neuroimaging have substantively informed the pathophysiology of numerous adult neurological and psychiatric disorders. While structural neuroimaging is readily acquired in sedated young children, pediatric application of functional neuroimaging has been limited by the behavioral demands of in-scanner task performance. Here, we investigated whether functional magnetic resonance imaging (fMRI) acquired during natural sleep and without experimental stimulation offers a viable strategy for studying young children. We targeted the lengthy epoch of non-rapid eye movement, stage 3 (NREM3) sleep typically observed at sleep onset in sleep-deprived children. Seven healthy, preschool-aged children (24-58 months) were studied, acquiring fMRI measurements of cerebral blood flow (CBF) and of intrinsic connectivity networks (ICNs), with concurrent sleep-stage monitoring. ICN data (T2* fMRI) were reliably obtained during NREM3 sleep; CBF data (arterial spin labeled fMRI) were not reliably obtained, as scanner noises disrupted sleep. Applying independent component analysis (ICA) to T2* data, distinct ICNs were observed which corresponded closely with those reported in the adult literature. Notably, a network associated with orthography in adults was not observed, suggesting that ICNs exhibit a developmental trajectory. We conclude that resting-state fMRI obtained in sleep is a promising paradigm for neurophysiological investigations of young children.