Studying the brain from adolescence to adulthood through sparse multi-view matrix factorisations

Men and women differ in specific cognitive abilities and in the expression of several neuropsychiatric conditions. Such findings could be attributed to sex hormones, brain differences, as well as a number of environmental variables. Existing research on identifying sex-related differences in brain structure have predominantly used cross-sectional studies to investigate, for instance, differences in average gray matter volumes (GMVs). In this article we explore the potential of a recently proposed multi-view matrix factorisation (MVMF) methodology to study structural brain changes in men and women that occur from adolescence to adulthood. MVMF is a multivariate variance decomposition technique that extends principal component analysis to "multi-view" datasets, i.e. where multiple and related groups of observations are available. In this application, each view represents a different age group. MVMF identifies latent factors explaining shared and age-specific contributions to the observed overall variability in GMVs over time. These latent factors can be used to produce low-dimensional visualisations of the data that emphasise age-specific effects once the shared effects have been accounted for. The analysis of two datasets consisting of individuals born prematurely as well as healthy controls provides evidence to suggest that the separation between males and females becomes increasingly larger as the brain transitions from adolescence to adulthood. We report on specific brain regions associated to these variance effects.Comment: Submitted to the 6th International Workshop on Pattern Recognition in Neuroimaging (PRNI

A multimodal imaging study of recognition memory in very preterm born adults

Very preterm (<32 weeks of gestation) birth is associated with structural brain alterationsand memory impairments throughout childhood and adolescence. Here, we used functional MRI(fMRI) to study the neuroanatomy of recognition memory in 49 very preterm-born adults and 50 con-trols (mean age: 30 years) during completion of a task involving visual encoding and recognition ofabstract pictures. T1-weighted and diffusion-weighted images were also collected. Bilateral hippocam-pal volumes were calculated and tractography of the fornix and cingulum was performed and assessedin terms of volume and hindrance modulated orientational anisotropy (HMOA). Online recognitionmemory task performance, assessed with A scores, was poorer in the very preterm compared with thecontrol group. Analysis of fMRI data focused on differences in neural activity between the recognitionand encoding trials. Very preterm born adults showed decreased activation in the right middle frontalgyrus and posterior cingulate cortex/precuneus and increased activation in the left inferior frontalgyrus and bilateral lateral occipital cortex (LOC) compared with controls. Hippocampi, fornix and cin-gulum volume was significantly smaller and fornix HMOA was lower in very preterm adults. Amongall the structural and functional brain metrics that showed statistically significant group differences,LOC activation was the best predictor of online task performance (P 5 0.020). In terms of associationbetween brain function and structure, LOC activation was predicted by fornix HMOA in the pretermgroup only (P 5 0.020). These results suggest that neuroanatomical alterations in very preterm bornindividuals may be underlying their poorer recognition memory performance

The Developing Human Connectome Project Neonatal Data Release

The Developing Human Connectome Project has created a large open science resource which provides researchers with data for investigating typical and atypical brain development across the perinatal period. It has collected 1228 multimodal magnetic resonance imaging (MRI) brain datasets from 1173 fetal and/or neonatal participants, together with collateral demographic, clinical, family, neurocognitive and genomic data from 1173 participants, together with collateral demographic, clinical, family, neurocognitive and genomic data. All subjects were studied in utero and/or soon after birth on a single MRI scanner using specially developed scanning sequences which included novel motion-tolerant imaging methods. Imaging data are complemented by rich demographic, clinical, neurodevelopmental, and genomic information. The project is now releasing a large set of neonatal data; fetal data will be described and released separately. This release includes scans from 783 infants of whom: 583 were healthy infants born at term; as well as preterm infants; and infants at high risk of atypical neurocognitive development. Many infants were imaged more than once to provide longitudinal data, and the total number of datasets being released is 887. We now describe the dHCP image acquisition and processing protocols, summarize the available imaging and collateral data, and provide information on how the data can be accessed

The architecture of functional lateralisation and its relationship to callosal connectivity in the human brain

Many functions of the human brain are lateralised i.e. associated more strongly with either the left or the right hemisphere of the brain. Here, the authors report the first complete map of functional asymmetries in the human brain, and its relationship with structural inter-hemispheric connectivity