206 research outputs found
Effect of perinatal adversity on structural connectivity of the developing brain
Globally, preterm birth (defined as birth at <37 weeks of gestation) affects
around 11% of deliveries and it is closely associated with cerebral palsy,
cognitive impairments and neuropsychiatric diseases in later life.
Magnetic Resonance Imaging (MRI) has utility for measuring different
properties of the brain during the lifespan. Specially, diffusion MRI has been
used in the neonatal period to quantify the effect of preterm birth on white
matter structure, which enables inference about brain development and
injury.
By combining information from both structural and diffusion MRI, is it possible
to calculate structural connectivity of the brain. This involves calculating a
model of the brain as a network to extract features of interest. The process
starts by defining a series of nodes (anatomical regions) and edges
(connections between two anatomical regions). Once the network is created,
different types of analysis can be performed to find features of interest,
thereby allowing group wise comparisons.
The main frameworks/tools designed to construct the brain connectome have
been developed and tested in the adult human brain. There are several
differences between the adult and the neonatal brain: marked variation in
head size and shape, maturational processes leading to changes in signal
intensity profiles, relatively lower spatial resolution, and lower contrast
between tissue classes in the T1 weighted image. All of these issues make
the standard processes to construct the brain connectome very challenging
to apply in the neonatal population. Several groups have studied the neonatal
structural connectivity proposing several alternatives to overcome these
limitations.
The aim of this thesis was to optimise the different steps involved in
connectome analysis for neonatal data. First, to provide accurate parcellation
of the cortex a new atlas was created based on a control population of term
infants; this was achieved by propagating the atlas from an adult atlas
through intermediate childhood spatio-temporal atlases using image
registration. After this the advanced anatomically-constrained tractography
framework was adapted for the neonatal population, refined using software
tools for skull-stripping, tissue segmentation and parcellation specially
designed and tested for the neonatal brain. Finally, the method was used to
test the effect of early nutrition, specifically breast milk exposure, on
structural connectivity in preterm infants. We found that infants with higher
exposure to breastmilk in the weeks after preterm birth had improved
structural connectivity of developing networks and greater fractional
anisotropy in major white matter fasciculi. These data also show that the
benefits are dose dependent with higher exposure correlating with increased
white matter connectivity.
In conclusion, structural connectivity is a robust method to investigate the
developing human brain. We propose an optimised framework for the
neonatal brain, designed for our data and using tools developed for the
neonatal brain, and apply it to test the effect of breastmilk exposure on
preterm infants
Perinatal Docosahexaenoic Acid Supplementation Improves Cognition and Alters Brain Functional Organization in Piglets.
Epidemiologic studies associate maternal docosahexaenoic acid (DHA)/DHA-containing seafood intake with enhanced cognitive development; although, it should be noted that interventional trials show inconsistent findings. We examined perinatal DHA supplementation on cognitive performance, brain anatomical and functional organization, and the brain monoamine neurotransmitter status of offspring using a piglet model. Sows were fed a control (CON) or a diet containing DHA (DHA) from late gestation throughout lactation. Piglets underwent an open field test (OFT), an object recognition test (ORT), and magnetic resonance imaging (MRI) to acquire anatomical, diffusion tensor imaging (DTI), and resting-state functional MRI (rs-fMRI) at weaning. Piglets from DHA-fed sows spent 95% more time sniffing the walls than CON in OFT and exhibited an elevated interest in the novel object in ORT, while CON piglets demonstrated no preference. Maternal DHA supplementation increased fiber length and tended to increase fractional anisotropy in the hippocampus of offspring than CON. DHA piglets exhibited increased functional connectivity in the cerebellar, visual, and default mode network and decreased activity in executive control and sensorimotor network compared to CON. The brain monoamine neurotransmitter levels did not differ in healthy offspring. Perinatal DHA supplementation may increase exploratory behaviors, improve recognition memory, enhance fiber tract integrity, and alter brain functional organization in offspring at weaning
What risk factors for Developmental Language Disorder can tell us about the neurobiological mechanisms of language development
Language is a complex multidimensional cognitive system that is connected to many neurocognitive capacities. The development of language is therefore strongly intertwined with the development of these capacities and their neurobiological substrates. Consequently, language problems, for example those of children with Developmental Language Disorder (DLD), are explained by a variety of etiological pathways and each of these pathways will be associated with specific risk factors. In this review, we attempt to link previously described factors that may interfere with language development to putative underlying neurobiological mechanisms of language development, hoping to uncover openings for future therapeutical approaches or interventions that can help children to optimally develop their language skills
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