Sunnaas Rehabilitation Hospital HT

Nesodden, Norway

Sunnaas Rehabilitation Hospital HT

Nesodden, Norway
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Guadalupe T.,Max Planck Institute for Psycholinguistics | Guadalupe T.,International Max Planck Research School for Language science | Mathias S.R.,Yale University | VanErp T.G.M.,University of California at Irvine | And 201 more authors.
Brain Imaging and Behavior | Year: 2016

The two hemispheres of the human brain differ functionally and structurally. Despite over a century of research, the extent to which brain asymmetry is influenced by sex, handedness, age, and genetic factors is still controversial. Here we present the largest ever analysis of subcortical brain asymmetries, in a harmonized multi-site study using meta-analysis methods. Volumetric asymmetry of seven subcortical structures was assessed in 15,847 MRI scans from 52 datasets worldwide. There were sex differences in the asymmetry of the globus pallidus and putamen. Heritability estimates, derived from 1170 subjects belonging to 71 extended pedigrees, revealed that additive genetic factors influenced the asymmetry of these two structures and that of the hippocampus and thalamus. Handedness had no detectable effect on subcortical asymmetries, even in this unprecedented sample size, but the asymmetry of the putamen varied with age. Genetic drivers of asymmetry in the hippocampus, thalamus and basal ganglia may affect variability in human cognition, including susceptibility to psychiatric disorders. © 2016 The Author(s)


Alnaes D.,University of Oslo | Kaufmann T.,University of Oslo | Richard G.,University of Oslo | Duff E.P.,University of Oxford | And 6 more authors.
NeuroImage | Year: 2015

In line with the notion of a continuously active and dynamic brain, functional networks identified during rest correspond with those revealed by task-fMRI. Characterizing the dynamic cross-talk between these network nodes is key to understanding the successful implementation of effortful cognitive processing in healthy individuals and its breakdown in a variety of conditions involving aberrant brain biology and cognitive dysfunction. We employed advanced network modeling on fMRI data collected during a task involving sustained attentive tracking of objects at two load levels and during rest. Using multivariate techniques, we demonstrate that attentional load levels can be significantly discriminated, and from a resting-state condition, the accuracy approaches 100%, by means of estimates of between-node functional connectivity. Several network edges were modulated during task engagement: The dorsal attention network increased connectivity with a visual node, while decreasing connectivity with motor and sensory nodes. Also, we observed a decoupling between left and right hemisphere dorsal visual streams. These results support the notion of dynamic network reconfigurations based on attentional effort. No simple correspondence between node signal amplitude change and node connectivity modulations was found, thus network modeling provides novel information beyond what is revealed by conventional task-fMRI analysis. The current decoding of attentional states confirms that edge connectivity contains highly predictive information about the mental state of the individual, and the approach shows promise for the utilization in clinical contexts. © 2015 Elsevier Inc.


PubMed | Sunnaas Rehabilitation Hospital HT and University of Oslo
Type: Journal Article | Journal: NeuroRehabilitation | Year: 2014

Magnetic resonance imaging (MRI) has brought about advances in the fields of brain plasticity and lifespan brain change, that might be of special interest for cognitive rehabilitation research and, eventually, in clinical practice. Parallel, intensive cognitive training studies show promising results for the prospect of retraining some of the impaired functioning following acquired brain injury.However, cognitive training research is largely performed without concurrent assessments of brain structural change and reorganization, which could have addressed possible mechanisms of training-related neuroplasticity.Criticism of cognitive training studies is often focused on lack of ecologically valid, daily-living assessments of treatment effect, and on whether the applied cognitive measures overlap too much with the training exercises. Yet, the present paper takes another point of view, where the relevance of recent MRI research of brain plasticity to the field of cognitive rehabilitation is examined.Arguably, treatment ought to be measured at the same level of the International Classification of Functioning, Disability and Health model, as it is targeting. In the case of cognitive training that will be the body structure and body function levels.MRI has shown promise to detect macro- and microstructural activity-related changes in the brain following intensive training.


PubMed | Sunnaas Rehabilitation Hospital HT and University of Oslo
Type: | Journal: NeuroImage | Year: 2015

Attentive tracking requires sustained object-based attention, rather than passive vigilance or rapid attentional shifts to brief events. Several theories of tracking suggest a mechanism of indexing objects that allows for attentional resources to be directed toward the moving targets. Imaging studies have shown that cortical areas belonging to the dorsal frontoparietal attention network increase BOLD-signal during multiple object tracking (MOT). Among these areas, some studies have assigned IPS a particular role in object indexing, but the neuroimaging evidence has been sparse. In the present study, we tested participants on a continuous version of the MOT task in order to investigate how cortical areas engage in functional networks during attentional tracking. Specifically, we analyzed the data using eigenvector centrality mapping (ECM) analysis, which provides estimates of individual voxels connectedness with hub-like parts of the functional network. The results obtained using permutation based voxel-wise statistics support the proposed role for the IPS in object indexing as this region displayed increased centrality during tracking as well as increased functional connectivity with both prefrontal and visual perceptual cortices. In contrast, the opposite pattern was observed for the SPL, with decreasing centrality, as well as reduced functional connectivity with the visual and frontal cortices, in agreement with a hypothesized role for SPL in attentional shifts. These findings provide novel evidence that IPS and SPL serve different functional roles during MOT, while at the same time being highly engaged during tracking as measured by BOLD-signal changes.


PubMed | National Institute for Physiological science, Charité - Medical University of Berlin, Kunming Medical University, University of Nottingham and 55 more.
Type: | Journal: Brain imaging and behavior | Year: 2016

The two hemispheres of the human brain differ functionally and structurally. Despite over a century of research, the extent to which brain asymmetry is influenced by sex, handedness, age, and genetic factors is still controversial. Here we present the largest ever analysis of subcortical brain asymmetries, in a harmonized multi-site study using meta-analysis methods. Volumetric asymmetry of seven subcortical structures was assessed in 15,847 MRI scans from 52 datasets worldwide. There were sex differences in the asymmetry of the globus pallidus and putamen. Heritability estimates, derived from 1170 subjects belonging to 71 extended pedigrees, revealed that additive genetic factors influenced the asymmetry of these two structures and that of the hippocampus and thalamus. Handedness had no detectable effect on subcortical asymmetries, even in this unprecedented sample size, but the asymmetry of the putamen varied with age. Genetic drivers of asymmetry in the hippocampus, thalamus and basal ganglia may affect variability in human cognition, including susceptibility to psychiatric disorders.

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