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Berlin, Germany

Battistella G.,University of Lausanne | Niederhauser J.,University of Lausanne | Fornari E.,University of Lausanne | Hippolyte L.,University Hospitals Geneva Medical Center | And 10 more authors.
Neurobiology of Aging

Fragile X-associated tremor/ataxia syndrome (FXTAS), a late-onset movement disorder affecting FMR1 premutation carriers, is associated with cerebral and cerebellar lesions. The aim of this study was to test whether computational anatomy can detect similar patterns in asymptomatic FMR1 premutation carriers (mean age 46.7 years) with qualitatively normal -appearing grey and white matter on brain MRI. We used a multimodal imaging protocol to characterize brain anatomy by automated assessment of gray matter volume and white matter properties. Structural changes in the hippocampus and in the cerebellar motor network with decreased gray matter volume in lobule VI and white matter alterations of the corresponding afferent projections through the middle cerebellar peduncles are demonstrated. Diffuse subcortical white matter changes in both hemispheres, without corresponding gray matter alterations, are only identified through age × group interactions. We interpret the hippocampal fimbria and cerebellar changes as early alterations with a possible neurodevelopmental origin. In contrast, progression of the diffuse cerebral hemispheric white matter changes suggests a neurodegenerative process, leading to late-onset lesions, which may mark the imminent onset of FXTAS. © 2013 Elsevier Inc. Source

Schaefer A.,Max Planck Institute for Human Cognitive and Brain Sciences | Margulies D.S.,Max Planck Institute for Human Cognitive and Brain Sciences | Lohmann G.,Max Planck Institute for Biological Cybernetics | Gorgolewski K.J.,Max Planck Institute for Human Cognitive and Brain Sciences | And 7 more authors.
Frontiers in Human Neuroscience

Network studies of large-scale brain connectivity have demonstrated that highly connected areas, or "hubs, " are a key feature of human functional and structural brain organization. We use resting-state functional MRI data and connectivity clustering to identify multi-network hubs and show that while hubs can belong to multiple networks their degree of integration into these different networks varies dynamically over time. The extent of the network variation was related to the connectedness of the hub. In addition, we found that these network dynamics were inversely related to positive self-generated thoughts reported by individuals and were further decreased with older age. Moreover, the left caudate varied its degree of participation between a default mode subnetwork and a limbic network. This variation was predictive of individual differences in the reports of past-related thoughts. These results support an association between ongoing thought processes and network dynamics and offer a new approach to investigate the brain dynamics underlying mental experience. © 2014 Schaefer, Margulies, Lohmann, Gorgolewski, Smallwood, Kiebel and Villringer. Source

Schaefer A.,Max Planck Institute for Human Cognitive and Brain Sciences | Quinque E.M.,Max Planck Institute for Human Cognitive and Brain Sciences | Kipping J.A.,Max Planck Institute for Human Cognitive and Brain Sciences | Arelin K.,Max Planck Institute for Human Cognitive and Brain Sciences | And 12 more authors.
Journal of Cerebral Blood Flow and Metabolism

Cerebral small vessel disease, mainly characterized by white matter lesions and lacunes, has a high clinical impact as it leads to vascular dementia. Recent studies have shown that this disease impairs frontoparietal networks. Here, we apply resting-state magnetic resonance imaging and data-driven whole-brain imaging analysis methods (eigenvector centrality) to investigate changes of the functional connectome in early small vessel disease. We show reduced connectivity in frontoparietal networks, whereas connectivity increases in the cerebellum. These functional changes are closely related to white matter lesions and typical neuropsychological deficits associated with small vessel disease. © 2014 ISCBFM. Source

Goltz D.,Max Planck Institute for Human Cognitive and Brain Sciences | Goltz D.,University of Leipzig | Goltz D.,University of Hamburg | Gundlach C.,Max Planck Institute for Human Cognitive and Brain Sciences | And 10 more authors.
Journal of Neuroscience

Previous studies on sustained tactile attention draw conclusions about underlying cortical networks by averaging over experimental conditions without considering attentional variance in single trials. This may have formed an imprecise picture of brain processes underpinning sustained tactile attention. In the present study, we simultaneously recorded EEG-fMRI and used modulations of steady state somatosensory evoked potentials (SSSEPs) as a measure of attentional trial-by-trial variability. Therefore, frequency-tagged streams of vibrotactile stimulations were simultaneously presented to both index fingers. Human participants were cued to sustain attention to either the left or right finger stimulation and to press a button whenever they perceived a target pulse embedded in the to-be-attended stream. In-line with previous studies, a classical general linear model (GLM) analysis based on cued attention conditions revealed increased activity mainly in somatosensory and cerebellar regions. Yet, parametric modeling of the BOLD response using simultaneously recorded SSSEPs as a marker of attentional trial-by-trial variability quarried the intraparietal sulcus (IPS). The IPS in turn showed enhanced functional connectivity to a modality-unspecific attention network. However, this was only revealed on the basis of cued attention conditions in the classical GLM. By considering attentional variability as captured by SSSEPs, the IPS showed increased connectivity to a sensorimotor network, underpinning attentional selection processes between competing tactile stimuli and action choices (press a button or not). Thus, the current findings highlight the potential value by considering attentional variations in single trials and extend previous knowledge on the role of the IPS in tactile attention. © 2015 the authors. Source

Boehringer A.,Max Planck Institute for Human Cognitive and Brain Sciences | Boehringer A.,Central Institute for Mental Health | Macher K.,Max Planck Institute for Human Cognitive and Brain Sciences | Dukart J.,Max Planck Institute for Human Cognitive and Brain Sciences | And 6 more authors.
Brain Stimulation

Background: Neuroimaging studies show cerebellar activations in a wide range of cognitive tasks and patients with cerebellar lesions often present cognitive deficits suggesting a cerebellar role in higher-order cognition. Objective: We used cathodal transcranial direct current stimulation (tDCS), known to inhibit neuronal excitability, over the cerebellum to investigate if cathodal tDCS impairs verbal working memory, an important higher-order cognitive faculty. Method: We tested verbal working memory as measured by forward and backward digit spans in 40 healthy young participants before and after applying cathodal tDCS (2 mA, stimulation duration 25 min) to the right cerebellum using a randomized, sham-controlled, double-blind, cross-over design. In addition, we tested the effect of cerebellar tDCS on word reading, finger tapping and a visually cued sensorimotor task. Results: In line with lower digit spans in patients with cerebellar lesions, cerebellar tDCS reduced forward digit spans and blocked the practice dependent increase in backward digit spans. No effects of tDCS on word reading, finger tapping or the visually cued sensorimotor task were found. Conclusion: Our results support the view that the cerebellum contributes to verbal working memory as measured by forward and backward digit spans. Moreover, the induction of reversible "virtual cerebellar lesions" in healthy individuals by means of tDCS may improve our understanding of the mechanistic basis of verbal working memory deficits in patients with cerebellar lesions. © 2013 Elsevier Inc. All rights reserved. Source

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