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]

Aberrant functional network connectivity in psychopathy from a large (N = 985) forensic sample.

Sat, 03/03/2018 - 15:00

Aberrant functional network connectivity in psychopathy from a large (N = 985) forensic sample.

Hum Brain Mapp. 2018 Mar 02;:

Authors: Espinoza FA, Vergara VM, Reyes D, Anderson NE, Harenski CL, Decety J, Rachakonda S, Damaraju E, Rashid B, Miller RL, Koenigs M, Kosson DS, Harenski K, Kiehl KA, Calhoun VD

Abstract
Psychopathy is a personality disorder characterized by antisocial behavior, lack of remorse and empathy, and impaired decision making. The disproportionate amount of crime committed by psychopaths has severe emotional and economic impacts on society. Here we examine the neural correlates associated with psychopathy to improve early assessment and perhaps inform treatments for this condition. Previous resting-state functional magnetic resonance imaging (fMRI) studies in psychopathy have primarily focused on regions of interest. This study examines whole-brain functional connectivity and its association to psychopathic traits. Psychopathy was hypothesized to be characterized by aberrant functional network connectivity (FNC) in several limbic/paralimbic networks. Group-independent component and regression analyses were applied to a data set of resting-state fMRI from 985 incarcerated adult males. We identified resting-state networks (RSNs), estimated FNC between RSNs, and tested their association to psychopathy factors and total summary scores (Factor 1, interpersonal/affective; Factor 2, lifestyle/antisocial). Factor 1 scores showed both increased and reduced functional connectivity between RSNs from seven brain domains (sensorimotor, cerebellar, visual, salience, default mode, executive control, and attentional). Consistent with hypotheses, RSNs from the paralimbic system-insula, anterior and posterior cingulate cortex, amygdala, orbital frontal cortex, and superior temporal gyrus-were related to Factor 1 scores. No significant FNC associations were found with Factor 2 and total PCL-R scores. In summary, results suggest that the affective and interpersonal symptoms of psychopathy (Factor 1) are associated with aberrant connectivity in multiple brain networks, including paralimbic regions.

PMID: 29498761 [PubMed - as supplied by publisher]

Functional connectivity changes in Systemic Lupus Erythematosus patients - a resting state study.

Sat, 03/03/2018 - 15:00

Functional connectivity changes in Systemic Lupus Erythematosus patients - a resting state study.

Brain Connect. 2018 Mar 02;:

Authors: Nystedt J, Mannfolk P, Nilsson P, Bengtsson A, Jönsen A, Sundgren PC, Strandberg O

Abstract
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 = 37.0 y, range = 18.2-52.0 y) and 20 gender and age-matched controls (mean age = 36.2 y, range = 23.3-52.2 y) in conjunction with clinical examination and laboratory testing. Whole-brain voxelwise functional connectivity analysis with permutation testing was performed to extract network components that differed in lupus-patients relative healthy controls.
RESULTS: Lupus-patients exhibited both inter- and intranetwork hypo- and hyperconnectivity involving several crucial networks. We found reduced connectivity within the default mode network (DMN), the central executive network (CEN) and in-between the DMN and CEN in lupus-patients. Increased connectivity was primarily observed within and between the sensory motor network (SMN) in lupus-patients when compared to healthy controls. Comparing lupus patients with and without neuropsychiatric symptoms, hypoconnectivity was more pronounced in the group with neuropsychiatric complaints. The functional connectivity of SLE-patients was both positively and negatively correlated to duration of disease.
CONCLUSION: We conclude that SLE patients in general and NPSLE-patients in particular experience altered brain connectivity. These patterns may be due both to direct neuronal damage as well as compensatory mechanisms through neuronal rewiring and recruitment and may partly explain neuropsychiatric symptoms in SLE-patients.

PMID: 29498293 [PubMed - as supplied by publisher]

Treadmill walking exercise training and brain function in multiple sclerosis: Preliminary evidence setting the stage for a network-based approach to rehabilitation.

Sat, 03/03/2018 - 15:00

Treadmill walking exercise training and brain function in multiple sclerosis: Preliminary evidence setting the stage for a network-based approach to rehabilitation.

Mult Scler J Exp Transl Clin. 2018 Jan-Mar;4(1):2055217318760641

Authors: Sandroff BM, Wylie GR, Sutton BP, Johnson CL, DeLuca J, Motl RW

Abstract
Exercise training has been identified as a highly promising approach for managing the cognitive consequences of multiple sclerosis (MS). This study represents a secondary analysis of resting-state functional connectivity (RSFC) magnetic resonance imaging data from a pilot treadmill walking exercise training intervention for improving cognitive processing speed (CPS) in MS. There were large intervention effects on RSFC between the thalamus and right superior frontal gyrus (d = 1.92) and left medial frontal gyrus (d = 1.70). There further were moderate-to-large intervention effects on CPS (d = 0.72). Such preliminary data highlight FC within thalamocortical circuitry as a potential target for rehabilitation interventions for improving CPS in cognitively impaired individuals with MS.

PMID: 29497559 [PubMed]

The Influence of Preprocessing Steps on Graph Theory Measures Derived from Resting State fMRI.

Sat, 03/03/2018 - 15:00

The Influence of Preprocessing Steps on Graph Theory Measures Derived from Resting State fMRI.

Front Comput Neurosci. 2018;12:8

Authors: Gargouri F, Kallel F, Delphine S, Ben Hamida A, Lehéricy S, Valabregue R

Abstract
Resting state functional MRI (rs-fMRI) is an imaging technique that allows the spontaneous activity of the brain to be measured. Measures of functional connectivity highly depend on the quality of the BOLD signal data processing. In this study, our aim was to study the influence of preprocessing steps and their order of application on small-world topology and their efficiency in resting state fMRI data analysis using graph theory. We applied the most standard preprocessing steps: slice-timing, realign, smoothing, filtering, and the tCompCor method. In particular, we were interested in how preprocessing can retain the small-world economic properties and how to maximize the local and global efficiency of a network while minimizing the cost. Tests that we conducted in 54 healthy subjects showed that the choice and ordering of preprocessing steps impacted the graph measures. We found that the csr (where we applied realignment, smoothing, and tCompCor as a final step) and the scr (where we applied realignment, tCompCor and smoothing as a final step) strategies had the highest mean values of global efficiency (eg) . Furthermore, we found that the fscr strategy (where we applied realignment, tCompCor, smoothing, and filtering as a final step), had the highest mean local efficiency (el) values. These results confirm that the graph theory measures of functional connectivity depend on the ordering of the processing steps, with the best results being obtained using smoothing and tCompCor as the final steps for global efficiency with additional filtering for local efficiency.

PMID: 29497372 [PubMed]

Segregation of the human basal forebrain using resting state functional MRI.

Sat, 03/03/2018 - 15:00

Segregation of the human basal forebrain using resting state functional MRI.

Neuroimage. 2018 Feb 26;:

Authors: Markello RD, Spreng RN, Luh WM, Anderson AK, De Rosa E

Abstract
The basal forebrain (BF) is poised to play an important neuromodulatory role in brain regions important to cognition due to its broad projections and complex neurochemistry. While significant in vivo work has been done to elaborate BF function in nonhuman rodents and primates, comparatively limited work has examined the in vivo function of the human BF. In the current study we used multi-echo resting state functional magnetic resonance imaging (rs-fMRI) from 100 young adults (18-34 years) to assess the potential segregation of human BF nuclei as well as their associated projections. Multi-echo processing provided significant gains in SNR throughout the brain as compared to traditional single-echo processing, with some of the largest increases observed in the BF. Bottom-up clustering of voxel-wise BF functional connectivity maps yielded adjacent functional clusters within the BF that closely aligned with the distinct, hypothesized nuclei important to cognition: the nucleus basalis of Meynert (NBM) and the medial septum/diagonal band of Broca (MS/DB). Examining their separate functional connections, the NBM and MS/DB revealed distinct projection patterns, suggesting a conservation of nuclei-specific functional connectivity with homologous regions known to be anatomically innervated by the BF. Specifically, the NBM demonstrated coupling with a widespread cortical network as well as the amygdala, whereas the MS/DB revealed coupling with a more circumscribed network, including the orbitofrontal cortex and hippocampal complex. Collectively, these in vivo rs-fMRI data demonstrate that the human BF nuclei support distinct aspects of resting-state functional networks, suggesting that the human BF may be a neuromodulatory hub important for orchestrating network dynamics.

PMID: 29496614 [PubMed - as supplied by publisher]

Changes in brain connectivity during a sham-controlled, transcranial magnetic stimulation trial for depression.

Fri, 03/02/2018 - 13:40
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Changes in brain connectivity during a sham-controlled, transcranial magnetic stimulation trial for depression.

J Affect Disord. 2018 Feb 21;232:143-151

Authors: Taylor SF, Ho SS, Abagis T, Angstadt M, Maixner DF, Welsh RC, Hernandez-Garcia L

Abstract
BACKGROUND: The subgenual anterior cingulate cortex (sgACC) has been implicated in major depressive disorder (MDD), and this study evaluated sgACC connectivity before and after repetitive transcranial magnetic stimulation (rTMS) treatment.
METHODS: Thirty-two MDD patients entered a sham-controlled, double-blinded, randomized trial of rTMS to the left dorsolateral prefrontal cortex (dlFPC). Subjects underwent resting state functional magnetic resonance imaging before and after 20 sessions of high frequency rTMS. Seed voxels identified the affective network (AN; sgACC, amygdala), default mode network (DMN; posterior cingulate cortex [PCC]), and fronto-parietal network (FPN; dlPFC stimulation site).
RESULTS: There was no significant effect of active rTMS over sham on the primary outcome measure (Montgomery-Asberg Depression Scale rating), with both groups improving over time, and no specific effect of rTMS (sham vs active) on connectivity. However, among patients who showed significant improvement, sgACC connectivity decreased for sham (to AN, trend to DMN) and active rTMS responders (to AN, DMN, FPN), but not in non-responders, who tended to maintain connectivity. Including subjects who started with sham but then received open-label active treatment, baseline connectivity from the PCC to the anterior insula was greater in non-responders compared to responders (n = 27, excluding 5 sham responders).
LIMITATIONS: The sample size was small; the stimulation target was non-standard, and the lack of a significant clinical effect of rTMS limits conclusions about negative findings.
CONCLUSIONS: sgACC connectivity reduces along with depressive symptoms, not specific to rTMS therapy. Altered connectivity of DMN with anterior insula may reflect a type of patient less likely to respond to an intervention.

PMID: 29494898 [PubMed - as supplied by publisher]

Aberrant intrinsic functional connectivity in thalamo-cortical networks in major depressive disorder.

Fri, 03/02/2018 - 13:40
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Aberrant intrinsic functional connectivity in thalamo-cortical networks in major depressive disorder.

CNS Neurosci Ther. 2018 Feb 28;:

Authors: Kong QM, Qiao H, Liu CZ, Zhang P, Li K, Wang L, Li JT, Su Y, Li KQ, Yan CG, Mitchell PB, Si TM

Abstract
OBJECTIVE: Growing evidence has implicated dysfunction of the thalamus and its projection cortical targets in depression. However, the anatomical specificity of thalamo-cortical connectivity in major depressive disorder (MDD) remains unknown due to the regional heterogeneity of the thalamus and limited methods to examine this.
METHODS: Resting-state fMRI was collected on 70 MDD patients and 70 healthy controls. The thalamus was parcellated based on connectivity with six predefined cortical regions of interest (ROIs). The segmented thalamic nuclei were used as seeds to map connectivity with the rest of the whole brain. The cortical-to-thalamus connectivity values and thalamus-based connectivity maps were compared between groups.
RESULTS: The cortical ROIs demonstrated correlations with spatially distinct zones within the thalamus. We found a trend toward reduced parietal ROI-to-thalamus connectivity in MDD. Importantly, MDD patients demonstrated reduced connectivity between prefrontal and parietal thalamus ROIs and bilateral middle frontal gyrus (MFG) and the right posterior default mode network (DMN) and between the prefrontal and motor thalamus ROIs and lateral temporal regions. Conversely, increased connectivity emerged between the motor thalamus ROI and right MFG and right medial frontal gyrus/anterior cingulate; between motor/somatosensory thalamus ROIs and right posterior DMN; between prefrontal/somatosensory thalamus ROIs and cerebellum; and between the parietal thalamus ROI and left insula.
CONCLUSIONS: This study is the first to examine the anatomical specificity of thalamo-cortical connectivity disturbances in MDD. Subjects with MDD demonstrated altered thalamo-cortical connectivity characterized by a complex pattern of region-dependent hypo- or hyperconnectivity. We therefore speculate that selectively modulating the connectivity of thalamo-cortical circuitry may be a potential novel therapeutic mechanism for MDD.

PMID: 29493113 [PubMed - as supplied by publisher]

Management of Obstructive Hydrocephalus in Pregnant Patient.

Fri, 03/02/2018 - 13:40
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Management of Obstructive Hydrocephalus in Pregnant Patient.

Asian J Neurosurg. 2018 Jan-Mar;13(1):123-127

Authors: Ekşi MŞ, Öğrenci A, Batçık OE, Koban O

Abstract
De novo obstructive hydrocephalus is a rare event during pregnancy. There are only case reports presented in literature. We aimed to discuss the pathophysiological basis and management options with an exemplary case presentation and review of the current literature. A 28-year-old G2P1 patient presented to our clinic with headache, vomiting, and deteriorated vision at the 8th week of gestation. She had no history of central nervous system infection or trauma. A brain magnetic resonance imaging was obtained. There was hydrocephalus due to cerebral aqueduct stenosis (Evan's index of 58%). She was managed conservatively with bed rest and diuretics; however, she got no relief. A ventriculoperitoneal shunt was inserted at the 13th week of gestation. At the 38th week, she had cesarean section (C/S) due to previous history of C/S in the first pregnancy and present cord entanglement of the fetus. C/S was conducted under epidural anesthesia after conforming she had no increased intra cranial pressure findings. Delivery was uneventful with a healthy newborn. Obstructive hydrocephalus is a very rare complication during pregnancy. Hydrocephalus becomes obvious and necessitates treatment, before the third trimester of pregnancy. Timely diagnosis, especially differentiation from preeclampsia, is a life-saving step. If no complication happens during intervention for hydrocephalus, spontaneous vaginal delivery is a safe way of delivery for both mother's and newborn's well-being. C/S should be saved for obstetrical indications and can be conducted under epidural anesthesia if intracranial pressure is kept under control. Interdisciplinary approach of neurosurgeons and anesthesiologists is pivotal for delicate care of the patient and the baby.

PMID: 29492141 [PubMed]

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