New resting-state fMRI related studies at PubMed

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Multivariate dynamical modelling of structural change during development.

Wed, 03/07/2018 - 13:00
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Multivariate dynamical modelling of structural change during development.

Neuroimage. 2017 Feb 15;147:746-762

Authors: Ziegler G, Ridgway GR, Blakemore SJ, Ashburner J, Penny W

Abstract
Here we introduce a multivariate framework for characterising longitudinal changes in structural MRI using dynamical systems. The general approach enables modelling changes of states in multiple imaging biomarkers typically observed during brain development, plasticity, ageing and degeneration, e.g. regional gray matter volume of multiple regions of interest (ROIs). Structural brain states follow intrinsic dynamics according to a linear system with additional inputs accounting for potential driving forces of brain development. In particular, the inputs to the system are specified to account for known or latent developmental growth/decline factors, e.g. due to effects of growth hormones, puberty, or sudden behavioural changes etc. Because effects of developmental factors might be region-specific, the sensitivity of each ROI to contributions of each factor is explicitly modelled. In addition to the external effects of developmental factors on regional change, the framework enables modelling and inference about directed (potentially reciprocal) interactions between brain regions, due to competition for space, or structural connectivity, and suchlike. This approach accounts for repeated measures in typical MRI studies of development and aging. Model inversion and posterior distributions are obtained using earlier established variational methods enabling Bayesian evidence-based comparisons between various models of structural change. Using this approach we demonstrate dynamic cortical changes during brain maturation between 6 and 22 years of age using a large openly available longitudinal paediatric dataset with 637 scans from 289 individuals. In particular, we model volumetric changes in 26 bilateral ROIs, which cover large portions of cortical and subcortical gray matter. We account for (1) puberty-related effects on gray matter regions; (2) effects of an early transient growth process with additional time-lag parameter; (3) sexual dimorphism by modelling parameter differences between boys and girls. There is evidence that the regional pattern of sensitivity to dynamic hidden growth factors in late childhood is similar across genders and shows a consistent anterior-posterior gradient with strongest impact to prefrontal cortex (PFC) brain changes. Finally, we demonstrate the potential of the framework to explore the coupling of structural changes across a priori defined subnetworks using an example of previously established resting state functional connectivity.

PMID: 27979788 [PubMed - indexed for MEDLINE]

Effectiveness and neural mechanisms of home-based telerehabilitation in patients with stroke based on fMRI and DTI: A study protocol for a randomized controlled trial.

Tue, 03/06/2018 - 12:00

Effectiveness and neural mechanisms of home-based telerehabilitation in patients with stroke based on fMRI and DTI: A study protocol for a randomized controlled trial.

Medicine (Baltimore). 2018 Jan;97(3):e9605

Authors: Chen J, Liu M, Sun D, Jin Y, Wang T, Ren C

Abstract
BACKGROUND: Stroke is one of leading diseases causing adult death and disability worldwide. Home-based telerehabilitation has become a novel approach for stroke patients as effective as conventional rehabilitation, and more convenient and economical than conventional rehabilitation. However, there is no study assessing the mechanism of home-based telerehabilitation in promoting motor recovery among stroke patients with hemiplegic.
AIMS: This study is designed to determine the efficacy and explore the mechanism of motor recovery after home-based telerehabilitation in stroke patients with motor deficits.
METHODS/DESIGN: In a single-blinded randomized controlled pilot study, patients with acute subcortical stroke (n = 40) are assigned to receive home-based telerehabilitation or conventional rehabilitation. Task-based or resting-state functional magnetic resonance imaging (rs-fMRI), diffusion tensor imaging (DTI), and Fugl-Meyer assessment (FMA) score will acquired before and after rehabilitation. Activation volume of bilateral primary motor (M1), supplementary motor area (SMA), premotor cortex (PMC); lateralization index (LI) of interhemispheric M1, SMA, and PMC; functional connectivity of bilateral M1, SMA, PMC; fractional anisotropy (FA) will be measured; correlation analyses will be performed between neuroimaging biomarkers and FMA score pre- and postrehabilitation.
DISCUSSION: We present a study design and rationale to explore the effectiveness and neural mechanism of home-based rehabilitation for stroke patients with motor deficits. The study limitations related to the small-amount sample. Moreover, home-based rehabilitation may provide an alternative means of recovery for stroke patients. Ultimately, results of this trial will help to understand the neural mechanism of home-based telerehabilitation among stroke patients with hand movement disorder.

PMID: 29504985 [PubMed - in process]

Functional MRI registration with tissue-specific patch-based functional correlation tensors.

Tue, 03/06/2018 - 12:00
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Functional MRI registration with tissue-specific patch-based functional correlation tensors.

Hum Brain Mapp. 2018 Mar 05;:

Authors: Zhou Y, Zhang H, Zhang L, Cao X, Yang R, Feng Q, Yap PT, Shen D

Abstract
Population studies of brain function with resting-state functional magnetic resonance imaging (rs-fMRI) rely on accurate intersubject registration of functional areas. This is typically achieved through registration using high-resolution structural images with more spatial details and better tissue contrast. However, accumulating evidence has suggested that such strategy cannot align functional regions well because functional areas are not necessarily consistent with anatomical structures. To alleviate this problem, a number of registration algorithms based directly on rs-fMRI data have been developed, most of which utilize functional connectivity (FC) features for registration. However, most of these methods usually extract functional features only from the thin and highly curved cortical grey matter (GM), posing great challenges to accurate estimation of whole-brain deformation fields. In this article, we demonstrate that additional useful functional features can also be extracted from the whole brain, not restricted to the GM, particularly the white-matter (WM), for improving the overall functional registration. Specifically, we quantify local anisotropic correlation patterns of the blood oxygenation level-dependent (BOLD) signals using tissue-specific patch-based functional correlation tensors (ts-PFCTs) in both GM and WM. Functional registration is then performed by integrating the features from different tissues using the multi-channel large deformation diffeomorphic metric mapping (mLDDMM) algorithm. Experimental results show that our method achieves superior functional registration performance, compared with conventional registration methods.

PMID: 29504193 [PubMed - as supplied by publisher]

Reduced corticostriatal functional connectivity in temporomandibular disorders.

Tue, 03/06/2018 - 12:00
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Reduced corticostriatal functional connectivity in temporomandibular disorders.

Hum Brain Mapp. 2018 Mar 05;:

Authors: He S, Li F, Gu T, Ma H, Li X, Zou S, Huang X, Lui S, Gong Q, Chen S

Abstract
Although temporomandibular disorders (TMD) have been associated with abnormal gray matter volumes in cortical areas and in the striatum, the corticostriatal functional connectivity (FC) of patients with TMD has not been studied. Here, we studied 30 patients with TMD and 20 healthy controls that underwent clinical evaluations, including Helkimo indices, pain assessments, and resting-state functional magnetic resonance imaging scans. The FCs of the striatal regions with the other brain areas were examined with a seed-based approach. As seeds, we used the dorsal caudate, ventral caudate/nucleus accumbens, dorsal caudal putamen, and ventral rostral putamen regions. Voxel-wise comparisons with controls revealed that the patients with TMD exhibited reduced FCs in the ventral corticostriatal circuitry, between the ventral striatum and ventral frontal cortices, including the anterior cingulate cortex and anterior insula; in the dorsal corticostriatal circuitry, between the dorsal striatum and the dorsal cortices, including the precentral gyrus and supramarginal gyrus; and also within the striatum. Additionally, we explored correlations between the reduced corticostriatal FCs and clinical measurements. These results directly supported the hypothesis that TMD is associated with reduced FCs in brain corticostriatal networks and that these reduced FCs may underlie the deficits in motor control, pain processing, and cognition in TMD. Our findings may contribute to the understanding of the etiologies and pathologies of TMD.

PMID: 29504182 [PubMed - as supplied by publisher]

Riccati-Regularized Precision Matrices for Neuroimaging.

Tue, 03/06/2018 - 12:00
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Riccati-Regularized Precision Matrices for Neuroimaging.

Inf Process Med Imaging. 2017 Jun;10265:275-286

Authors: Honnorat N, Davatzikos C

Abstract
The introduction of graph theory in neuroimaging has provided invaluable tools for the study of brain connectivity. These methods require the definition of a graph, which is typically derived by estimating the effective connectivity between brain regions through the optimization of an ill-posed inverse problem. Considerable efforts have been devoted to the development of methods extracting sparse connectivity graphs. The present paper aims at highlighting the benefits of an alternative approach. We investigate low-rank L2 regularized matrices recently introduced under the denomination of Riccati regularized precision matrices. We demonstrate their benefits for the analysis of cortical thickness map and the extraction of functional biomarkers from resting state fMRI scans. In addition, we explain how speed and result quality can be further improved with random projections. The promising results obtained using the Human Connectome Project dataset, as well as, the numerous possible extensions and applications suggest that Riccati precision matrices might usefully complement current sparse approaches.

PMID: 29503515 [PubMed - in process]

Altered amygdala and hippocampus effective connectivity in mild cognitive impairment patients with depression: a resting-state functional MR imaging study with granger causality analysis.

Tue, 03/06/2018 - 12:00
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Altered amygdala and hippocampus effective connectivity in mild cognitive impairment patients with depression: a resting-state functional MR imaging study with granger causality analysis.

Oncotarget. 2017 Apr 11;8(15):25021-25031

Authors: Zheng LJ, Yang GF, Zhang XY, Wang YF, Liu Y, Zheng G, Lu GM, Zhang LJ, Han Y

Abstract
Neuroimaging studies have demonstrated that the major depression disorder would increase the risk of dementia in the older with amnestic cognitive impairment. We used granger causality analysis algorithm to explore the amygdala- and hippocampus-based directional connectivity patterns in 12 patients with major depression disorder and amnestic cognitive impairment (mean age: 69.5 ± 10.3 years), 13 amnestic cognitive impairment patients (mean age: 72.7 ± 8.5 years) and 14 healthy controls (mean age: 64.7 ± 7.0 years). Compared with amnestic cognitive impairment patients and control groups respectively, the patients with both major depression disorder and amnestic cognitive impairment displayed increased effective connectivity from the right amygdala to the right lingual and calcarine gyrus, as well as to the bilateral supplementary motor areas. Meanwhile, the patients with both major depression disorder and amnestic cognitive impairment had enhanced effective connectivity from the left superior parietal gyrus, superior and middle occipital gyrus to the left hippocampus, the z values of which was also correlated with the scores of mini-mental state examination and auditory verbal learning test-immediate recall. Our findings indicated that the directional effective connectivity of right amygdala - occipital-parietal lobe - left hippocampus might be the pathway by which major depression disorder inhibited the brain activity in patients with amnestic cognitive impairment.

PMID: 28212570 [PubMed - indexed for MEDLINE]

Gene expression profiles in peripheral blood mononuclear cells correlate with salience network activity in chronic visceral pain: A pilot study.

Tue, 03/06/2018 - 12:00
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Gene expression profiles in peripheral blood mononuclear cells correlate with salience network activity in chronic visceral pain: A pilot study.

Neurogastroenterol Motil. 2017 Jun;29(6):

Authors: Gupta A, Cole S, Labus JS, Joshi S, Nguyen TJ, Kilpatrick LA, Tillisch K, Naliboff BD, Chang L, Mayer EA

Abstract
BACKGROUND: Distinct gene expression profiles in peripheral blood mononuclear cells (PBMCs) consistent with increased sympathetic nervous system activity have been described in different populations under chronic stress. Neuroinflammatory brain changes, possibly related to the migration of primed monocytes to the brain, have been implicated in the pathophysiology of chronic pain. Irritable bowel syndrome (IBS) is a stress-sensitive gastrointestinal disorder associated with altered brain-gut interactions and increased sympathetic/vagal tone and anxiety. Reports about immune alterations in IBS are conflicting. This pilot study aimed to test how PBMC gene expression inflammatory profiles are correlated with altered brain signatures in the salience system.
METHODS: Sixteen IBS and 16 healthy controls (HCs) completed resting state MRI scans. Gene expression profiles in PBMCs were assessed using human transcriptome array-2. Bioinformatic analyses determined differential expression of PBMCs between IBS and HCs. Partial least squares, a multivariate analysis technique, was used to identify disease correlations between PBMC gene expression profiles and functional activity in the brain's salience network.
KEY RESULTS: Regions of the salience network, including the mid cingulate cortex, and mid and superior temporal gyrus were positively correlated with several pro-inflammatory genes (interleukin 6, APOL2) in IBS, but negatively correlated with several anti-inflammatory genes (KRT8, APOA4) in HCs.
CONCLUSIONS & INFERENCES: Based on rodent studies, one may speculate that chronically activated stress signaling pathways in IBS maintain a pro-inflammatory state in the periphery. Alternatively, primed monocytes may migrate to the brain during stress, inducing regional neuroinflammatory changes in salience regions involved in the modulation of visceral sensitivity.

PMID: 28191693 [PubMed - indexed for MEDLINE]

Functional connectivity of task context representations in prefrontal nodes of the multiple demand network.

Mon, 03/05/2018 - 17:00

Functional connectivity of task context representations in prefrontal nodes of the multiple demand network.

Brain Struct Funct. 2018 Mar 03;:

Authors: Stiers P, Goulas A

Abstract
A subset of regions in the lateral and medial prefrontal cortex and the anterior insula increase their activity level whenever a cognitive task becomes more demanding, regardless of the specific nature of this demand. During execution of a task, these areas and the surrounding cortex temporally encode aspects of the task context in spatially distributed patterns of activity. It is not clear whether these patterns reflect underlying anatomical subnetworks that still exist when task execution has finished. We use fMRI in 12 participants performing alternating blocks of three cognitive tasks to address this question. A first data set is used to define multiple demand regions in each participant. A second dataset from the same participants is used to determine multiple demand voxel assemblies with a preference for one task over the others. We then show that these voxels remain functionally coupled during execution of non-preferred tasks and that they exhibit stronger functional connectivity during rest. This indicates that the assemblies of task preference sharing voxels reflect patterns of underlying anatomical connections. Moreover, we show that voxels preferring the same task have more similar whole brain functional connectivity profiles that are consistent across participants. This suggests that voxel assemblies differ in patterns of input-output connections, most likely reflecting task demand-specific information exchange.

PMID: 29502145 [PubMed - as supplied by publisher]

Default Mode Network Disruption in Stroke-Free Patients with Atrial Fibrillation.

Mon, 03/05/2018 - 17:00

Default Mode Network Disruption in Stroke-Free Patients with Atrial Fibrillation.

Cerebrovasc Dis. 2018 Mar 02;45(1-2):78-84

Authors: Silva DS, Avelar WM, de Campos BM, Lino APBL, Balthazar MLF, Figueiredo MJO, Cendes F, Coan AC

Abstract
BACKGROUND: Atrial fibrillation (AF) is a widely accepted risk for causing stroke. However, recent studies show AF as a risk factor for dementia, even without causing stroke. The mechanisms by which dementia develops in stroke-free patients with AF are still poorly understood and the association of AF with abnormal function of brain networks activities, such as the default mode network (DMN), has not been previously studied. We aimed to determine whether, in the absence of stroke and dementia, patients with AF have abnormal resting-state brain networks compared to controls without AF.
METHODS: Twenty-one stroke-free patients with AF and 21 age- and sex-matched controls without AF underwent brain functional magnetic resonance imaging acquired at a 3.0 Tesla scanner. During the exam, the subjects were instructed to lie still with eyes closed. At first-level analysis, connectivity of the DMN was obtained for all subjects. Second-level analysis compared the DMN connectivity between AF patients and controls with a general linear model (two-sample t test, p < 0.05, False Discovery Rate corrected, minimum of 50 contiguous voxels).
RESULTS: Patients with AF compared with controls showed decreased connectivity in regions of the DMN including the frontal lobe (left medial frontal gyrus, left superior frontal gyrus and anterior cingulate), left angular gyrus, and bilateral precuneus.
CONCLUSIONS: Stroke-free patients with AF have evidence of abnormal DMN connectivity. This study adds evidence to the occurrence of cerebral dysfunction in patients with AF.

PMID: 29502113 [PubMed - as supplied by publisher]

Correlations between CSF proteins and spontaneous neuronal activity in Parkinson's disease.

Mon, 03/05/2018 - 17:00

Correlations between CSF proteins and spontaneous neuronal activity in Parkinson's disease.

Neurosci Lett. 2018 Feb 28;:

Authors: Guo T, Guan X, Zeng Q, Xuan M, Gu Q, Xu X, Zhang M

Abstract
The relationship between cerebrospinal fluid (CSF) proteins and brain function in Parkinson's disease (PD) is not explained clearly. We investigated the correlations between CSF proteins and spontaneous neuronal activity in PD patients via fractional amplitude of low-frequency fluctuation (fALFF) using the Parkinson's Progression Markers Initiative database. Twenty-eight PD patients underwent resting-state functional magnetic resonance imaging in "off" status and lumbar puncture within a month. Correlation analyses between CSF proteins and fALFF value in whole brain as well as clinical assessment scores were performed. We found CSF total tau (t-tau) level was negatively correlated with fALFF in posterior cingulate gyrus. And fALFF in posterior cingulate gyrus was positively correlated with Hopkins Verbal Learning Test-Revised recognition discrimination index. Besides, alpha-synuclein (α-syn) level was correlated with fALFF in bilateral inferior frontal gyrus. This study provides evidence that CSF proteins may have a relationship with brain function related to cognitive status in PD patients.

PMID: 29501577 [PubMed - as supplied by publisher]

Abnormal resting-state functional connectivity in posterior cingulate cortex of Parkinson's disease with mild cognitive impairment and dementia.

Sun, 03/04/2018 - 16:00

Abnormal resting-state functional connectivity in posterior cingulate cortex of Parkinson's disease with mild cognitive impairment and dementia.

CNS Neurosci Ther. 2018 Mar 03;:

Authors: Zhan ZW, Lin LZ, Yu EH, Xin JW, Lin L, Lin HL, Ye QY, Chen XC, Pan XD

Abstract
OBJECTIVE: To investigate changes in the functional connectivity (FC) pattern in the posterior cingulate cortex (PCC) of Parkinson's disease (PD) patients with mild cognitive impairment and dementia by employing resting-state functional magnetic resonance imaging (RS-fMRI).
METHODS: Twenty-seven PD patients with different cognitive status and 9 healthy control subjects (control group) were enrolled for RS-fMRI. The RS-fMRI data were analyzed with DPARSF and REST software. Regions with changed functional connectivity were determined by the seed-based voxelwise method and compared between groups. Correlation between the intensity of FC and the MoCA scores of PD group was analyzed.
RESULTS: Parametric maps showed statistical increases in PCC functional connectivity in PD-MCI patients and decreases in PCC connectivity in PDD patients. The latter group of patients also showed evidence for increased connectivity between prefrontal cortices and posterior cerebellum. A significant positive correlation was found between the MoCA scores and the strength of PCC connectivity in the angular gyrus and posterior cerebellum and a negative correlation between MoCA scores and PCC connectivity in all other brain regions.
CONCLUSION: When patients transition from PD-NCI to PD-MCI, there appears to be an increase in functional connectivity in the PCC, suggesting an expansion of the cortical network. Another new network (a compensatory prefrontal cortical-cerebellar loop) later develops during the transition from PD-MCI to PDD.

PMID: 29500931 [PubMed - as supplied by publisher]

Sleeve Gastrectomy Recovering Disordered Brain Function in Subjects with Obesity: a Longitudinal fMRI Study.

Sun, 03/04/2018 - 16:00

Sleeve Gastrectomy Recovering Disordered Brain Function in Subjects with Obesity: a Longitudinal fMRI Study.

Obes Surg. 2018 Mar 02;:

Authors: Li P, Shan H, Liang S, Nie B, Liu H, Duan S, Huang Q, Zhang T, Dong G, Guo Y, Du J, Gao H, Ma L, Li D, Shan B

Abstract
OBJECTIVE: Bariatric surgery could recover regional dysfunction of cerebral cortex. However, it is unknown whether bariatric surgery could recover the global-level dysfunction in subjects with obesity. The aim of this study was to investigate the effect of bariatric surgery on global-level dysfunction in subjects with obesity by resting-state functional magnetic resonance imaging (fMRI).
METHODS: Resting-state fMRI was used to investigate dysfunction of whole-brain in 34 subjects with obesity and 34 age-and gender-matched normal-weight subjects, in which 17 subjects with obesity received sleeve gastrectomy. Fractional amplitude of low-frequency fluctuation (fALFF) and functional connectivity (FC) among the whole brain were used to estimate the brain functional differences among the preoperative subjects, postoperative subjects, and the controls.
RESULTS: The preoperative subjects compared to controls had decreased resting-state activities in reward processing and cognitive control regions such as orbitofrontal cortex, middle frontal gyrus, superior frontal gyrus, and gyrus rectus. It was important that increased FC was also found in these regions. Correlation analysis showed that body mass index (BMI) was associated with these decreased activity and increased FC. More importantly, the dysfunction in these regions was recovered by the bariatric surgery.
CONCLUSIONS: These results suggest that bariatric surgery-induced weight loss could reverse the global-level dysfunction in subjects with obesity. The dysfunction in these regions might play a key role in the development of obesity, which might serve as a biomarker in the treatment of obesity.

PMID: 29500671 [PubMed - as supplied by publisher]

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