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Brain Connectivity

Jessika Nystedt, Peter Mannfolk, Petra Nilsson, Anders Bengtsson, Andreas Jönsen, Pia C Sundgren, Olof Strandberg
PURPOSE: To investigate resting state functional connectivity of lupus-patients and associated subgroups according to the ACR NPSLE case definitions (ACR ad Hoc 1999). Additionally, we investigated whether or not the observed alterations correlated with disease duration, SLE-disease activity index-2000 (SLEDAI-2k) and Systemic Lupus International Collaborating Clinical/ACR organ damage index (SDI)-scores. MATERIAL AND METHOD: Anatomical 3T MRI and resting state-fMRI (rs-fMRI) were performed in 61 female lupus-patients (mean age = 37...
March 2, 2018: Brain Connectivity
Marco Fuscà, Philipp Ruhnau, Toralf Neuling, Nathan Weisz
Transcranial alternating current stimulation (tACS) has been proposed as a tool to draw causal inferences on the role of oscillatory activity in cognitive functioning and has the potential to induce long-term changes in cerebral networks. However, effectiveness of tACS underlies high variability and dependencies, which, as previous modeling works have suggested, may be mediated by local and network-level brain states. We used magnetoencephalography (MEG) to record brain activity from 17 healthy participants at rest as they kept their eyes open (EO) or closed (EC) while being stimulated either with sham, weak, or strong alpha-tACS using a montage commonly assumed to target occipital areas...
February 24, 2018: Brain Connectivity
Jacob Charles Wright Billings, Shella Dawn Keilholz
Global signal regression is a controversial processing step for resting state functional magnetic resonance imaging, partly because the source of the global blood oxygen level-dependent (BOLD) signal remains unclear. On the one hand, nuisance factors such as motion can readily introduce coherent BOLD changes across the whole brain. On the other hand, the global signal has been linked to neural activity and vigilance levels, suggesting that it contains important neurophysiological information and should not be discarded...
February 12, 2018: Brain Connectivity
Deniz Vatansever, Anne E Manktelow, Barbara J Sahakian, David Krishna Menon, Emmanuel A Stamatakis
The default mode network (DMN) is typically associated with off-task internal mentation, or with goal-oriented tasks that require self-referential processing such as autobiographical planning. However, recent reports suggest a broader involvement of the DMN in higher cognitive processing. In line with this view, we report global connectivity changes centred on the main DMN hubs of precuneus and posterior cingulate cortex during an fMRI-based visuospatial version of the Tower of London planning task. Importantly, functional connectivity of these regions and the left caudate shows a significant relationship with faster reaction time to correct responses only during the high-demand planning condition, thus offering further evidence for the DMN's engagement during visuospatial planning...
January 24, 2018: Brain Connectivity
John J Sidtis, Vijay Dhawan, David Eidelberg, Diana Van Lancker Sidtis
Language has been modeled as a rule governed behavior for generating an unlimited number of novel utterances using phonological, syntactic, and lexical processes. This view of language as essentially propositional is expanding as the role of formulaic expressions (e.g., you know, have a nice day, how are you?) is increasingly recognized. The basic features of the functional anatomy of this language system have been described by studies of brain damage: left lateralization for propositional language and greater right lateralization and basal ganglia involvement for formulaic expressions...
January 22, 2018: Brain Connectivity
Bhim M Adhikari, Charles M Epstein, Mukesh Dhamala
Generating movement rhythms is known to involve a network of distributed brain regions associated with motor planning, control, execution, and perception of timing for the repertoire of motor actions. What brain areas are bound in the network and how the network activity is modulated by rhythmic complexity have not been completely explored. To contribute to answering these questions, we designed a study in which nine healthy participants performed simple to complex rhythmic finger movement tasks while undergoing simultaneous functional magnetic resonance imaging and electroencephalography (fMRI-EEG) recordings of their brain activity during the tasks and rest...
January 22, 2018: Brain Connectivity
Ali M Golestani, Zahra Faraji-Dana, Mohammad Kayvanrad, Kawin Setsompop, Simon J Graham, J Jean Chen
Simultaneous multislice echo-planar imaging (SMS-EPI) can enhance the spatiotemporal resolution of resting-state functional MRI (rs-fMRI) by encoding and simultaneously imaging "groups" of slices. However, phenomena, including respiration, cardiac pulsatility, respiration volume per time (RVT), and cardiac rate variation (CRV), referred to as "physiological processes," impact SMS-EPI rs-fMRI in a manner that is yet to be well characterized. In particular, physiological noise may incur aliasing and introduce spurious signals from one slice into another within the "slice group" in rs-fMRI data, resulting in a deleterious effect on resting-state functional connectivity MRI (rs-fcMRI) maps...
January 22, 2018: Brain Connectivity
Thomas Koenig, Pedro A Valdés-Sosa
We comment on a recent article published in Brain Connectivity (Hatz et al., 2016 ) that combined electroencephalography (EEG) microstate analysis with the phase-locking index (PLI) and found that the test-retest reliability of connectivity patterns as obtained by the PLI increased when the data had been previously parcellated into microstates. Although we acknowledge the need to parcellate the continuous data into periods that supposedly correspond to transiently stable patterns of connectivity, we believe that the approach chosen by the authors is seriously mistaken...
January 22, 2018: Brain Connectivity
Priya Santhanam, E Susan Duncan, Steven L Small
Cortical reorganization after stroke is thought to underlie functional improvement. Patterns of reorganization may differ depending on the amount of time since the stroke or the degree of improvement. We investigated these issues in a study of brain connectivity changes with aphasia therapy. Twelve individuals with chronic aphasia participated in a 6-week trial of imitation-based speech therapy. We assessed improvement on a repetition test and analyzed effective connectivity during functional magnetic resonance imaging (fMRI) of a speech observation task before and after therapy...
January 16, 2018: Brain Connectivity
Tien-Wen Lee, Shao-Wei Xue
Multi-modal neuroimaging research has become increasingly popular, and structure-function correspondence is tacitly assumed. Researchers have not yet adequately assessed whether the functional connectivity (FC) and structural connectivity (SC) of large-scale cortical networks are in agreement. Structural magnetic resonance imaging (sMRI), resting-state functional MRI (rfMRI) and diffusion weighted imaging (DWI) datasets from 36 healthy subjects (age 27.4) were selected from a Rockland sample (Enhanced Nathan Kline Institute)...
January 1, 2018: Brain Connectivity
Flor A Espinoza, Jessica A Turner, Victor M Vergara, Robyn L Miller, Eva Mennigen, Jingyu Liu, Maria B Misiura, Jennifer Ciarochi, Hans J Johnson, Jeffrey D Long, Henry J Bockholt, Vincent A Magnota, Jane S Paulsen, Vince D Calhoun
Huntington's disease (HD) is an inherited brain disorder characterized by progressive motor, cognitive and behavioral dysfunctions. It is caused by abnormally large trinucleotide cytosine-adenine-guanine (CAG) repeat expansions on exon 1 of the Huntingtin gene. CAG repeat length (CAG-RL) inversely correlates with an earlier age of onset. Region-based studies have shown that Huntington's disease gene mutation carriers (HDgmc) individuals (CAG-RL ≥ 36) present functional connectivity (FC) alterations in subcortical and default mode networks...
January 1, 2018: Brain Connectivity
Renee S Schluter, Jochem M Jansen, Ruth J van Holst, Wim van den Brink, Anna E Goudriaan
High frequency repetitive transcranial magnetic stimulation (HF-rTMS) has gained great interest in multiple clinical and research fields and is believed to accomplish its effect by influencing neuronal networks. The dlPFC is frequently chosen as the cortical target for HF-rTMS. However very little is known about the differential effect of HF-rTMS over the left and right dlPFC on intrinsic functional connectivity networks in patients or in healthy individuals. The current study assessed the differential effects of left or right HF-rTMS (corrected for sham) on intrinsic Independent Component Analysis (ICA) defined functional connectivity networks in a sample of 45 healthy individuals...
December 14, 2017: Brain Connectivity
Belinda Pletzer, TiAnni Harris
Sex, stimulus material and attention condition have previously been related to global advantage (faster responses to global targets than to local targets), as well as lateralization during global-local processing. It is presumed that the lateralization of brain functions is either related to the inhibitory influence of the dominant on the non-dominant hemisphere or reduced excitation between hemispheres. However, a direct relationship between the global advantage and lateralization, as well as inter-hemispheric connectivity has not been previously established...
December 10, 2017: Brain Connectivity
Venkatagiri Krishnamurthy, Lisa C Krishnamurthy, Dina M Schwam, Ashley Ealey, Jaemin Shin, Daphne Greenberg, Robin D Morris
It is well accepted that physiological noise (PN) obscures the detection of neural fluctuations in resting-state functional connectivity (rsFC) MRI. However, a clear consensus for an optimal PN correction (PNC) methodology and how it can impact the rsFC signal characteristics is still lacking. In this study, we probe the impact of three PNC methods: RETROICOR: (Glover, et al. 2000), ANATICOR: (Jo, et al. 2010), and RVTMBPM: (Bianciardi, et al. 2009). Using a reading network model, we systematically explore the effects of PNC optimization on sensitivity, specificity, and reproducibility of rsFC signals...
December 10, 2017: Brain Connectivity
Raíssa Benocci Thibes, Natalia P Novaes, Leandro T Lucato, Kenia R Campanholo, Luciano M Melo, Claudia C Leite, Edson Amaro, Egberto Reis Barbosa, Edson Bor-Seng-Shu, Ellison Fernando Cardoso, João Ricardo Sato
Parkinson's disease (PD) is a neurodegenerative disorder that affects motor skills and cognition. As brain structure and function are compromised, functional magnetic resonance imaging (fMRI) can be a helpful tool to further investigate how intrinsic connectivity is impaired on the disease. The precuneus and medial prefrontal cortex (mPFC) are hub regions involved on the default mode network (DMN), a system that is active during rest and related to cognitive processes. We hypothesized that PD patients would present a decrease in functional connectivity among these two regions and the rest of the brain...
December 2017: Brain Connectivity
Kaundinya Gopinath, Venkatagiri Krishnamurthy, Simon Lacey, K Sathian
A recent study (Eklund et al., 2016) has shown that cluster-wise family-wise error (FWE) rate corrected inferences made in parametric statistical methods based fMRI studies over the past couple of decades may have been invalid, particularly for cluster defining thresholds less stringent than p < 0.001; principally because the spatial autocorrelation functions (sACF) of fMRI data had been modeled incorrectly to follow a Gaussian form, whereas empirical data suggests otherwise (Eklund et al., 2016). Hence the residuals from general linear model (GLM) based fMRI activation estimates in these studies may not have possessed a homogenously Gaussian sACF (Eklund et al...
November 22, 2017: Brain Connectivity
Sheeba Arnold Anteraper, Xavier Guell, Susan Whitfield-Gabrieli, Christina Triantafyllou, Aaron Mattfeld, John D Gabrieli, Maiya Geddes
The subthalamic nucleus (STN) is a small structure situated deep in the mid-brain that exhibits wide-ranging functionality. In addition to its role in motor control, the STN is considered a hub for synchronizing aspects of emotion and cognition including attention, inhibitory control, motivation, and working memory. Evidence from neuroanatomical tracer studies suggests that the medial, ventromedial, and dorsolateral parts of the STN correspond to limbic, associative, and motor subdivisions respectively. While the extent of STN functional anatomical overlap remains unclear, BOLD imaging of the STN may provide complementary information about the diverse functions of this structure...
November 21, 2017: Brain Connectivity
Zack Y Shan, Kevin Finegan, Sandeep Bhuta, Timothy Ireland, Donald R Staines, Sonya M Marshall-Gradisnik, Leighton R Barnden
The chronic fatigue syndrome / myalgic encephalomyelitis (CFS) is a debilitating disease with unknown pathophysiology and no diagnostic test. This study investigated the default mode network (DMN) in order to understand the pathophysiology of CFS and to identify potential biomarkers. Using functional MRI (fMRI) collected from 72 subjects (45 CFS and 27 controls) with a temporal resolution of 0.798s, we evaluated the default mode network using static functional connectivity (FC), dynamic functional connectivity (DFC) and DFC complexity, blood oxygenation level dependent (BOLD) activation maps and complexity of activity...
November 20, 2017: Brain Connectivity
Anna Custo, Dimitri Van De Ville, William M Wells, Miralena I Tomescu, Denis Brunet, Christoph M Michel
Using electroencephalography (EEG) to elucidate the spontaneous activation of brain resting-state networks (RSNs) is nontrivial as the signal of interest is of low amplitude and it is difficult to distinguish the underlying neural sources. Using the principles of electric field topographical analysis, it is possible to estimate the meta-stable states of the brain (i.e., the resting-state topographies, so-called microstates). We estimated seven resting-state topographies explaining the EEG data set with k-means clustering (N = 164, 256 electrodes)...
November 17, 2017: Brain Connectivity
Elena Bilevicius, Stephen D Smith, Jennifer Kornelsen
Mindfulness refers to attending to moment-to-moment experiences with acceptance and no judgment. Several scales have been developed to quantify different components of mindfulness. The Mindful Attention Awareness Scale (MAAS) is particularly sensitive to trait mindfulness and is proposed to measure the attentional component of mindfulness. The purpose of the current study was to identify the neural correlates of the MAAS in four resting state networks related to attention-the default mode network (DMN), the salience network (SN), and the left and right central executive network (lCEN and rCEN)...
November 12, 2017: Brain Connectivity
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