New resting-state fMRI related studies at PubMed

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Long-term intensive gymnastic training induced changes in intra- and inter-network functional connectivity: an independent component analysis.

Mon, 07/24/2017 - 07:20
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Long-term intensive gymnastic training induced changes in intra- and inter-network functional connectivity: an independent component analysis.

Brain Struct Funct. 2017 Jul 21;:

Authors: Huang H, Wang J, Seger C, Lu M, Deng F, Wu X, He Y, Niu C, Wang J, Huang R

Abstract
Long-term intensive gymnastic training can induce brain structural and functional reorganization. Previous studies have identified structural and functional network differences between world class gymnasts (WCGs) and non-athletes at the whole-brain level. However, it is still unclear how interactions within and between functional networks are affected by long-term intensive gymnastic training. We examined both intra- and inter-network functional connectivity of gymnasts relative to non-athletes using resting-state fMRI (R-fMRI). R-fMRI data were acquired from 13 WCGs and 14 non-athlete controls. Group-independent component analysis (ICA) was adopted to decompose the R-fMRI data into spatial independent components and associated time courses. An automatic component identification method was used to identify components of interest associated with resting-state networks (RSNs). We identified nine RSNs, the basal ganglia network (BG), sensorimotor network (SMN), cerebellum (CB), anterior and posterior default mode networks (aDMN/pDMN), left and right fronto-parietal networks (lFPN/rFPN), primary visual network (PVN), and extrastriate visual network (EVN). Statistical analyses revealed that the intra-network functional connectivity was significantly decreased within the BG, aDMN, lFPN, and rFPN, but increased within the EVN in the WCGs compared to the controls. In addition, the WCGs showed uniformly decreased inter-network functional connectivity between SMN and BG, CB, and PVN, BG and PVN, and pDMN and rFPN compared to the controls. We interpret this generally weaker intra- and inter-network functional connectivity in WCGs during the resting state as a result of greater efficiency in the WCGs' brain associated with long-term motor skill training.

PMID: 28733834 [PubMed - as supplied by publisher]

Left Frontal Hub Connectivity during Memory Performance Supports Reserve in Aging and Mild Cognitive Impairment.

Sat, 07/22/2017 - 11:20

Left Frontal Hub Connectivity during Memory Performance Supports Reserve in Aging and Mild Cognitive Impairment.

J Alzheimers Dis. 2017 Jul 17;:

Authors: Franzmeier N, Hartmann JC, Taylor AN, Araque Caballero MA, Simon-Vermot L, Buerger K, Kambeitz-Ilankovic LM, Ertl-Wagner B, Mueller C, Catak C, Janowitz D, Stahl R, Dichgans M, Duering M, Ewers M

Abstract
Reserve in aging and Alzheimer's disease (AD) is defined as maintaining cognition at a relatively high level in the presence of neurodegeneration, an ability often associated with higher education among other life factors. Recent evidence suggests that higher resting-state functional connectivity within the frontoparietal control network, specifically the left frontal cortex (LFC) hub, contributes to higher reserve. Following up these previous resting-state fMRI findings, we probed memory-task related functional connectivity of the LFC hub as a neural substrate of reserve. In elderly controls (CN, n = 37) and patients with mild cognitive impairment (MCI, n = 17), we assessed global connectivity of the LFC hub during successful face-name association learning, using generalized psychophysiological interaction analyses. Reserve was quantified as residualized memory performance, accounted for gender and proxies of neurodegeneration (age, hippocampus atrophy, and APOE genotype). We found that greater education was associated with higher LFC-connectivity in both CN and MCI during successful memory. Furthermore, higher LFC-connectivity predicted higher residualized memory (i.e., reserve). These results suggest that higher LFC-connectivity contributes to reserve in both healthy and pathological aging.

PMID: 28731448 [PubMed - as supplied by publisher]

Shared atypical default mode and salience network functional connectivity between autism and schizophrenia.

Sat, 07/22/2017 - 11:20
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Shared atypical default mode and salience network functional connectivity between autism and schizophrenia.

Autism Res. 2017 Jul 21;:

Authors: Chen H, Uddin LQ, Duan X, Zheng J, Long Z, Zhang Y, Guo X, Zhang Y, Zhao J, Chen H

Abstract
Schizophrenia and autism spectrum disorder (ASD) are two prevalent neurodevelopmental disorders sharing some similar genetic basis and clinical features. The extent to which they share common neural substrates remains unclear. Resting-state fMRI data were collected from 35 drug-naïve adolescent participants with first-episode schizophrenia (15.6 ± 1.8 years old) and 31 healthy controls (15.4 ± 1.6 years old). Data from 22 participants with ASD (13.1 ± 3.1 years old) and 21 healthy controls (12.9 ± 2.9 years old) were downloaded from the Autism Brain Imaging Data Exchange. Resting-state functional networks were constructed using predefined regions of interest. Multivariate pattern analysis combined with multi-task regression feature selection methods were conducted in two datasets separately. Classification between individuals with disorders and controls was achieved with high accuracy (schizophrenia dataset: accuracy = 83%; ASD dataset: accuracy = 80%). Shared atypical brain connections contributing to classification were mostly present in the default mode network (DMN) and salience network (SN). These functional connections were further related to severity of social deficits in ASD (p = 0.002). Distinct atypical connections were also more related to the DMN and SN, but showed different atypical connectivity patterns between the two disorders. These results suggest some common neural mechanisms contributing to schizophrenia and ASD, and may aid in understanding the pathology of these two neurodevelopmental disorders. Autism Res 2017. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

PMID: 28730732 [PubMed - as supplied by publisher]

Functional connectivity and cognitive impairment in migraine with and without aura.

Sat, 07/22/2017 - 11:20
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Functional connectivity and cognitive impairment in migraine with and without aura.

J Headache Pain. 2017 Dec;18(1):72

Authors: Lo Buono V, Bonanno L, Corallo F, Pisani LR, Lo Presti R, Grugno R, Di Lorenzo G, Bramanti P, Marino S

Abstract
BACKGROUND: Several fMRI studies in migraine assessed resting state functional connectivity in different networks suggesting that this neurological condition was associated with brain functional alteration. The aim of present study was to explore the association between cognitive functions and cerebral functional connectivity, in default mode network, in migraine patients without and with aura, during interictal episodic attack.
METHODS: Twenty-eight migraine patients (14 without and 14 with aura) and 14 matched normal controls, were consecutively recruited. A battery of standardized neuropsychological test was administered to evaluate cognitive functions and all subjects underwent a resting state with high field fMRI examination.
RESULTS: Migraine patients did not show abnormalities in neuropsychological evaluation, while, we found a specific alteration in cortical network, if we compared migraine with and without aura. We observed, in migraine with aura, an increased connectivity in left angular gyrus, left supramarginal gyrus, right precentral gyrus, right postcentral gyrus, right insular cortex.
CONCLUSION: Our findings showed in migraine patients an alteration in functional connectivity architecture. We think that our results could be useful to better understand migraine pathogenesis.

PMID: 28730563 [PubMed - in process]

Abnormal resting state effective connectivity within the default mode network in major depressive disorder: A spectral dynamic causal modeling study.

Sat, 07/22/2017 - 11:20
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Abnormal resting state effective connectivity within the default mode network in major depressive disorder: A spectral dynamic causal modeling study.

Brain Behav. 2017 Jul;7(7):e00732

Authors: Li L, Li B, Bai Y, Liu W, Wang H, Leung HC, Tian P, Zhang L, Guo F, Cui LB, Yin H, Lu H, Tan Q

Abstract
INTRODUCTION: Understanding the neural basis underlying major depressive disorder (MDD) is essential for the diagnosis and treatment of this mental disorder. Aberrant activation and functional connectivity of the default mode network (DMN) have been consistently found in patients with MDD. It is not known whether effective connectivity within the DMN is altered in MDD.
OBJECTS: The primary object of this study is to investigate the effective connectivity within the DMN during resting state in MDD patients before and after eight weeks of antidepressant treatment.
METHODS: We defined four regions of the DMN (medial frontal cortex, posterior cingulate cortex, left parietal cortex, and right parietal cortex) for each participant using a group independent component analysis. The coupling parameters reflecting the causal interactions among the DMN regions were estimated using spectral dynamic causal modeling (DCM).
RESULTS: Twenty-seven MDD patients and 27 healthy controls were included in the statistical analysis. Our results showed declined influences from the left parietal cortex to other DMN regions in the pre-treatment patients as compared with healthy controls. After eight weeks of treatment, the influence from the right parietal cortex to the posterior cingulate cortex significantly decreased.
CONCLUSION: These findings suggest that the reduced excitatory causal influence of the left parietal cortex is the key alteration of the DMN in patients with MDD, and the disrupted causal influences that parietal cortex exerts on the posterior cingulate cortex is responsive to antidepressant treatment.

PMID: 28729938 [PubMed - in process]

Coherence of BOLD signal and electrical activity in the human brain during deep sevoflurane anesthesia.

Sat, 07/22/2017 - 11:20
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Coherence of BOLD signal and electrical activity in the human brain during deep sevoflurane anesthesia.

Brain Behav. 2017 Jul;7(7):e00679

Authors: Golkowski D, Ranft A, Kiel T, Riedl V, Kohl P, Rohrer G, Pientka J, Berger S, Preibisch C, Zimmer C, Mashour GA, Schneider G, Kochs EF, Ilg R, Jordan D

Abstract
INTRODUCTION: Changes in neural activity induce changes in functional magnetic resonance (fMRI) blood oxygenation level dependent (BOLD) signal. Commonly, increases in BOLD signal are ascribed to cellular excitation.
OBJECTIVE: The relationship between electrical activity and BOLD signal in the human brain was probed on the basis of burst suppression EEG. This condition includes two distinct states of high and low electrical activity.
METHODS: Resting-state simultaneous EEG and BOLD measurements were acquired during deep sevoflurane anesthesia with burst suppression EEG in nineteen healthy volunteers. Afterwards, fMRI volumes were assigned to one of the two states (burst or suppression) as defined by the EEG.
RESULTS: In the frontal, parietal and temporal lobes as well as in the basal ganglia, BOLD signal increased after burst onset in the EEG and decreased after onset of EEG suppression. In contrast, BOLD signal in the occipital lobe was anticorrelated to electrical activity. This finding was obtained consistently in a general linear model and in raw data.
CONCLUSIONS: In human brains exhibiting burst suppression EEG induced by sevoflurane, the positive correlation between BOLD signal and electrical brain activity could be confirmed in most gray matter. The exceptional behavior of the occipital lobe with an anticorrelation of BOLD signal and electrical activity might be due to specific neurovascular coupling mechanisms that are pronounced in the deeply anesthetized brain.

PMID: 28729926 [PubMed - in process]

Investigating Focal Connectivity Deficits in Alzheimer's Disease Using Directional Brain Networks Derived from Resting-State fMRI.

Sat, 07/22/2017 - 11:20
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Investigating Focal Connectivity Deficits in Alzheimer's Disease Using Directional Brain Networks Derived from Resting-State fMRI.

Front Aging Neurosci. 2017;9:211

Authors: Zhao S, Rangaprakash D, Venkataraman A, Liang P, Deshpande G

Abstract
Connectivity analysis of resting-state fMRI has been widely used to identify biomarkers of Alzheimer's disease (AD) based on brain network aberrations. However, it is not straightforward to interpret such connectivity results since our understanding of brain functioning relies on regional properties (activations and morphometric changes) more than connections. Further, from an interventional standpoint, it is easier to modulate the activity of regions (using brain stimulation, neurofeedback, etc.) rather than connections. Therefore, we employed a novel approach for identifying focal directed connectivity deficits in AD compared to healthy controls. In brief, we present a model of directed connectivity (using Granger causality) that characterizes the coupling among different regions in healthy controls and Alzheimer's disease. We then characterized group differences using a (between-subject) generative model of pathology, which generates latent connectivity variables that best explain the (within-subject) directed connectivity. Crucially, our generative model at the second (between-subject) level explains connectivity in terms of local or regionally specific abnormalities. This allows one to explain disconnections among multiple regions in terms of regionally specific pathology; thereby offering a target for therapeutic intervention. Two foci were identified, locus coeruleus in the brain stem and right orbitofrontal cortex. Corresponding disrupted connectivity network associated with the foci showed that the brainstem is the critical focus of disruption in AD. We further partitioned the aberrant connectomic network into four unique sub-networks, which likely leads to symptoms commonly observed in AD. Our findings suggest that fMRI studies of AD, which have been largely cortico-centric, could in future investigate the role of brain stem in AD.

PMID: 28729831 [PubMed]

Resting-State Fluctuations of EEG Sensorimotor Rhythm Reflect BOLD Activities in the Pericentral Areas: A Simultaneous EEG-fMRI Study.

Sat, 07/22/2017 - 11:20
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Resting-State Fluctuations of EEG Sensorimotor Rhythm Reflect BOLD Activities in the Pericentral Areas: A Simultaneous EEG-fMRI Study.

Front Hum Neurosci. 2017;11:356

Authors: Tsuchimoto S, Shibusawa S, Mizuguchi N, Kato K, Ebata H, Liu M, Hanakawa T, Ushiba J

Abstract
Blockade of the scalp electroencephalographic (EEG) sensorimotor rhythm (SMR) is a well-known phenomenon following attempted or executed motor functions. Such a frequency-specific power attenuation of the SMR occurs in the alpha and beta frequency bands and is spatially registered at primary somatosensory and motor cortices. Here, we hypothesized that resting-state fluctuations of the SMR in the alpha and beta frequency bands also covary with resting-state sensorimotor cortical activity, without involving task-related neural dynamics. The present study employed functional magnetic resonance imaging (fMRI) to investigate the neural regions whose activities were correlated with the simultaneously recorded SMR power fluctuations. The SMR power fluctuations were convolved with a canonical hemodynamic response function and correlated with blood-oxygen-level dependent (BOLD) signals obtained from the entire brain. Our findings show that the alpha and beta power components of the SMR correlate with activities of the pericentral area. Furthermore, brain regions with correlations between BOLD signals and the alpha-band SMR fluctuations were located posterior to those with correlations between BOLD signals and the beta-band SMR. These results are consistent with those of event-related studies of SMR modulation induced by sensory input or motor output. Our findings may help to understand the role of the sensorimotor cortex activity in contributing to the amplitude modulation of SMR during the resting state. This knowledge may be applied to the diagnosis of pathological conditions in the pericentral areas or the refinement of brain-computer interfaces using SMR in the future.

PMID: 28729830 [PubMed]

Altered intrinsic functional connectivity in the latent period of epileptogenesis in a temporal lobe epilepsy model.

Sat, 07/22/2017 - 11:20
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Altered intrinsic functional connectivity in the latent period of epileptogenesis in a temporal lobe epilepsy model.

Exp Neurol. 2017 Jul 17;:

Authors: Lee H, Jung S, Lee P, Jeong Y

Abstract
The latent period, a seizure-free phase, is the duration between brain injury and the onset of spontaneous recurrent seizures (SRSs) during epileptogenesis. The latent period is thought to involve several progressive pathophysiological events that lead to the evolution of the chronic epilepsy phase. Hence, it is vital to investigate the changes in the latent period during epileptogenesis in order to better understand temporal lobe epilepsy (TLE), and to achieve early diagnosis and appropriate management of the condition. Accordingly, recent studies with patients with TLE using resting-state functional magnetic resonance imaging (rs-fMRI) have reported that alterations of resting-state functional connectivity (rsFC) during the chronic period are associated with some clinical manifestations, including learning and memory impairments, emotional instability, and social behavior deficits, in addition to repetitive seizure episodes. In contrast, the changes in the intrinsic rsFC during epileptogenesis, particularly during the latent period, remain unclear. In this study, we investigated the alterations in intrinsic rsFC during the latent and chronic periods in a pilocarpine-induced TLE mouse model using intrinsic optical signal imaging (IOSI). This technique can monitor the changes in the local hemoglobin concentration according to neuronal activity and can help investigate large-scale brain intrinsic networks. After seeding on the anatomical regions of interest (ROIs) and calculating the correlation coefficients between each ROI, we established and compared functional correlation matrices and functional connectivity maps during the latent and chronic periods of epilepsy. We found a decrease in the interhemispheric rsFC at the frontal and temporal regions during both the latent and chronic periods. Furthermore, a significant decrease in the interhemispheric rsFC was observed in the somatosensory area during the chronic period. Changes in network configurations during epileptogenesis were examined by graph theoretical network analysis. Interestingly, increase in the power of low frequency oscillations was observed during the latent period. These results suggest that, even if there are no apparent ictal seizure events during the latent period, there are ongoing changes in the rsFC in the epileptic brain. Furthermore, these results suggest that the pathophysiology of epilepsy may be related to widespread altered intrinsic functional connectivity. These findings can help enhance our understanding of epileptogenesis, and accordingly, changes in intrinsic functional connectivity can serve as an early diagnosis.

PMID: 28729114 [PubMed - as supplied by publisher]

Learning-based structurally-guided construction of resting-state functional correlation tensors.

Sat, 07/22/2017 - 11:20
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Learning-based structurally-guided construction of resting-state functional correlation tensors.

Magn Reson Imaging. 2017 Jul 17;:

Authors: Zhang L, Zhang H, Chen X, Wang Q, Yap PT, Shen D

Abstract
Functional magnetic resonance imaging (fMRI) measures changes in blood-oxygenation-level-dependent (BOLD) signals to detect brain activities. It has been recently reported that the spatial correlation patterns of resting-state BOLD signals in the white matter (WM) also give WM information often measured by diffusion tensor imaging (DTI). These correlation patterns can be captured using functional correlation tensor (FCT), which is analogous to the diffusion tensor (DT) obtained from DTI. In this paper, we propose a noise-robust FCT method aiming at further improving its quality, and making it eligible for further neuroscience study. The novel FCT estimation method consists of three major steps: First, we estimate the initial FCT using a patch-based approach for BOLD signal correlation to improve the noise robustness. Second, by utilizing the relationship between functional and diffusion data, we employ a regression forest model to learn the mapping between the initial FCTs and the corresponding DTs using the training data. The learned forest can then be applied to predict the DTI-like tensors given the initial FCTs from the testing fMRI data. Third, we re-estimate the enhanced FCT by utilizing the DTI-like tensors as a feedback guidance to further improve FCT computation. We have demonstrated the utility of our enhanced FCTs in Alzheimer's disease (AD) diagnosis by identifying mild cognitive impairment (MCI) patients from normal subjects.

PMID: 28729016 [PubMed - as supplied by publisher]

Difference in resting-state fractional amplitude of low-frequency fluctuation between bipolar depression and unipolar depression patients.

Sat, 07/22/2017 - 11:20
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Difference in resting-state fractional amplitude of low-frequency fluctuation between bipolar depression and unipolar depression patients.

Eur Rev Med Pharmacol Sci. 2017 Apr;21(7):1541-1550

Authors: Yu HL, Liu WB, Wang T, Huang PY, Jie LY, Sun JZ, Wang C, Qian W, Xuan M, Gu QQ, Liu H, Zhang FL, Zhang MM

Abstract
OBJECTIVE: To investigate the difference in fractional amplitude of low-frequency fluctuation (fALFF) of localized brain activities in the resting-state between bipolar depression and unipolar depression patients and to find biological markers that differentiate the two groups of patients.
PATIENTS AND METHODS: Thirteen patients with bipolar depression, 15 patients with unipolar depression, and 16 healthy control subjects that were matched in age and years of education were subjected to 3.0 T resting-state functional magnetic resonance scans. The values of whole brain fALFF were calculated and statistical analysis was performed.
RESULTS: The fALFF-values of the right inferior temporal gyrus, left cerebellar posterior lobe, right middle temporal gyrus, left inferior frontal gyrus/insula, right inferior frontal gyrus/insula, left lingual gyrus and right middle temporal gyrus of the three groups showed significant differences (p < 0.05). Compared with the healthy control (HC) group, the fALFF-values of the unipolar depression (UD) patient group significantly increased in the right superior temporal gyrus, left insula, left inferior frontal gyrus, right inferior frontal gyrus, right supramarginal gyrus and right medial frontal gyrus but significantly decreased in the right medial occipital gyrus, left frontal lobe, right superior parietal lobule; the fALFF-values of the bipolar depression (BD) patient group significantly decreased in the left cerebellum posterior lobe, right lingual gyrus, left lingual gyrus, right middle temporal gyrus, left middle temporal gyrus, and left superior frontal gyrus and significantly increased in the right inferior frontal gyrus and left insula compared to those of the HC group; compared with those of the UD group, the fALFF-values of the BD group significantly decreased in the left middle occipital gyrus, right middle temporal gyrus, left middle frontal gyrus, and left medial frontal gyrus.
CONCLUSIONS: The brain activities of BD and UD patients in the resting-state exhibit abnormalities, which differ between the two groups of patients.

PMID: 28429352 [PubMed - indexed for MEDLINE]

Nonlinear modulation of interacting between COMT and depression on brain function.

Fri, 07/21/2017 - 10:20

Nonlinear modulation of interacting between COMT and depression on brain function.

Eur Psychiatry. 2017 Jun 09;45:6-13

Authors: Gong L, He C, Yin Y, Ye Q, Bai F, Yuan Y, Zhang H, Lv L, Zhang H, Zhang Z, Xie C

Abstract
BACKGROUND: The catechol-O-methyltransferase (COMT) gene is related to dopamine degradation and has been suggested to be involved in the pathogenesis of major depressive disorder (MDD). However, how this gene affects brain function properties in MDD is still unclear.
METHODS: Fifty patients with MDD and 35 cognitively normal participants underwent a resting-state functional magnetic resonance imaging scan. A voxelwise and data-drive global functional connectivity density (gFCD) analysis was used to investigate the main effects and the interactions of disease states and COMT rs4680 gene polymorphism on brain function.
RESULTS: We found significant group differences of the gFCD in bilateral fusiform area (FFA), post-central and pre-central cortex, left superior temporal gyrus (STG), rectal and superior temporal gyrus and right ventrolateral prefrontal cortex (vlPFC); abnormal gFCDs in left STG were positively correlated with severity of depression in MDD group. Significant disease×COMT interaction effects were found in the bilateral calcarine gyrus, right vlPFC, hippocampus and thalamus, and left SFG and FFA. Further post-hoc tests showed a nonlinear modulation effect of COMT on gFCD in the development of MDD. Interestingly, an inverted U-shaped modulation was found in the prefrontal cortex (control system) but U-shaped modulations were found in the hippocampus, thalamus and occipital cortex (processing system).
CONCLUSION: Our study demonstrated nonlinear modulation of the interaction between COMT and depression on brain function. These findings expand our understanding of the COMT effect underlying the pathophysiology of MDD.

PMID: 28728097 [PubMed - as supplied by publisher]

Local Brain Activity Differences Between Herpes Zoster and Postherpetic Neuralgia Patients: A Resting-State Functional MRI Study.

Fri, 07/21/2017 - 10:20

Local Brain Activity Differences Between Herpes Zoster and Postherpetic Neuralgia Patients: A Resting-State Functional MRI Study.

Pain Physician. 2017 Jul;20(5):E687-E699

Authors: Cao S, Li Y, Deng W, Qin B, Zhang Y, Xie P, Yuan J, Yu B, Yu T

Abstract
BACKGROUND: Herpes zoster (HZ) can develop into postherpetic neuralgia (PHN), both of which are painful diseases. PHN patients suffer chronic pain and emotional disorders. Previous studies showed that the PHN brain displayed abnormal activity and structural change, but the difference in brain activity between HZ and PHN is still not known.
OBJECTIVES: To identify regional brain activity changes in HZ and PHN brains with resting-state functional magnetic resonance imaging (rs-fMRI) technique, and to observe the differences between HZ and PHN patients.
STUDY DESIGN: Observational study.
SETTING: University hospital.
METHODS: Regional homogeneity (ReHo) and fractional aptitude of low-frequency fluctuation (fALFF) methods were employed to analysis resting-state brain activity. Seventy-three age and gender matched patients (50 HZ, 23 PHN) and 55 healthy controls were enrolled. ReHo and fALFF changes were analyzed to detect the functional abnormality in HZ and PHN brains.
RESULTS: Compared with healthy controls, HZ and PHN patients exhibited abnormal ReHo and fALFF values in classic pain-related brain regions (such as the frontal lobe, thalamus, insular, and cerebellum) as well as the brainstem, limbic lobe, and temporal lobe. When HZ developed to PHN, the activity in the vast area of the cerebellum significantly increased while that of some regions in the occipital lobe, temporal lobe, parietal lobe, and limbic lobe showed an apparent decrease.
LIMITATIONS: (a) Relatively short pain duration (mean 12.2 months) and small sample size (n = 23) for PHN group. (b) Comparisons at different time points (with paired t-tests) for each patient may minimize individual differences.
CONCLUSIONS: HZ and PHN induced local brain activity changed in the pain matrix, brainstem, and limbic system. HZ chronification induced functional change in the cerebellum, occipital lobe, temporal lobe, parietal lobe, and limbic lobe. These brain activity changes may be correlated with HZ-PHN transition.
KEY WORDS: Herpes zoster, postherpetic neuralgia, resting-state fMRI (rs-fMRI), regional homogeneity (ReHo), fractional aptitude of low-frequency fluctuation (fALFF).

PMID: 28727713 [PubMed - in process]

Altered putamen functional connectivity is associated with anxiety disorder in Parkinson's disease.

Fri, 07/21/2017 - 10:20

Altered putamen functional connectivity is associated with anxiety disorder in Parkinson's disease.

Oncotarget. 2017 Jul 05;:

Authors: Wang X, Li J, Yuan Y, Wang M, Ding J, Zhang J, Zhu L, Shen Y, Zhang H, Zhang K

Abstract
In this study, we used resting state-functional magnetic resonance imaging (rs-fMRI) to explore altered putamen functional connectivity (FC) in Parkinson's disease patients with anxiety disorder. We divided 65 Parkinson's disease patients into anxiety (PD-A; n=18) and non-anxiety (PD-NA; n=45) groups based on a Hamilton Anxiety Rating Scale cutoff score of 12. The PD-A patients exhibited altered putamen FC with cortical and subcortical regions. The PD-A patients showed enhanced putamen FC with the caudatum, which correlated with increased emotional processing during anxiety. Decreased putamen FC with the orbitofrontal gyrus and cerebellum also correlated with increased anxiety in Parkinson's disease. Our findings demonstrate that anxiety disorder in Parkinson's disease is associated with abnormal putamen FC networks, especially with caudatum, orbitofrontal gyrus and cerebellum.

PMID: 28727571 [PubMed - as supplied by publisher]

Columnar Segregation of Magnocellular and Parvocellular Streams in Human Extrastriate Cortex.

Fri, 07/21/2017 - 10:20
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Columnar Segregation of Magnocellular and Parvocellular Streams in Human Extrastriate Cortex.

J Neurosci. 2017 Jul 19;:

Authors: Tootell RBH, Nasr S

Abstract
'Magno- vs. parvo-cellular' (M-P) streams are fundamental to the organization of macaque visual cortex. Segregated, paired M-P streams extend from retina through LGN into V1. The M stream extends further into area V5/MT, and parts of V2. However elsewhere in visual cortex, it remains unclear whether M-P-derived information 1) becomes intermixed, or 2) remains segregated in M-P dominated columns and neurons. Here we tested whether M-P streams exist in extrastriate cortical columns, in 8 human subjects (4 female).We acquired high resolution fMRI at high field (7T), testing for M- and P-influenced columns within each of four cortical areas (V2, V3, V3A and V4), based on known functional distinctions in M-P streams in macaque: 1) color vs. luminance, 2) binocular disparity, 3) luminance contrast sensitivity, 4) peak spatial frequency, and 5) color/spatial interactions. Additional measurements of resting state activity (eyes closed) tested for segregated functional connections between these columns.We found M- and P-like functions and connections within and bbetween segregated cortical columns in V2, V3, and (in most experiments) area V4. Area V3A was dominated by the M stream, without significant influence from the P stream. These results suggest that M-P streams exist, and extend through, specific columns in early/middle stages of human extrastriate cortex.SIGNIFICANCE STATEMENTThe 'magnocellular' and 'parvocellular' (M-P) streams are fundamental components of primate visual cortical organization. These streams segregate both anatomical and functional properties in parallel, from retina through primary visual cortex. However in most higher order cortical sites, it is unknown whether such M-P streams exist, and/or what form those streams would take. Moreover it is unknown whether M-P streams exist in human cortex. Here, fMRI evidence measured at high field (7T) and high resolution revealed segregated M-P streams in four areas of human extrastriate cortex. These results suggest that M-P information is processed in segregated parallel channels throughout much of human visual cortex; the M-P streams are more than a convenient sorting property in earlier stages of the visual system.

PMID: 28724749 [PubMed - as supplied by publisher]

Disrupted small-world brain network topology in pure conduct disorder.

Fri, 07/21/2017 - 10:20
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Disrupted small-world brain network topology in pure conduct disorder.

Oncotarget. 2017 Jul 08;:

Authors: Lu FM, Zhou JS, Zhang J, Wang XP, Yuan Z

Abstract
OBJECTIVES: Conduct disorder (CD) is characterized by the violation of the rights of others or basic social rules and a repetitive, persistent pattern of antisocial and aggressive behaviors. A large number of functional and structural neuroimaging studies have identified widely abnormalities in specific brain regions in CD, but the alterations in the topological organization of functional networks among them remain largely unknown.
METHODS: Resting-state functional magnetic resonance imaging was applied to investigate the intrinsic functional connectivity in 18 pure CD patients and eighteen typically developing healthy controls. We first constructed the functional networks and then examined the CD-related alteration in topology properties using graph theoretical analysis.
RESULTS: Both the CD group and healthy controls exhibited small-world topology. However, the CD group showed decreased global and local efficiency. Changes in the nodal characteristics in CD group were found predominantly in the default-mode network, visual, and striatum regions. In addition, altered fronto-limbic-striatum network topology was found to have a relationship with clinical scores.
CONCLUSIONS: Our findings indicate the altered nodal topology of brain functional connectivity networks in CD.
SIGNIFICANCE: The results provide unequivocal evidence of a topological disruption in the brain networks that suggest some possible pathophysiological mechanisms underlying CD.

PMID: 28723654 [PubMed - as supplied by publisher]

Interhemispheric disconnectivity in the sensorimotor network in bipolar disorder revealed by functional connectivity and diffusion tensor imaging analysis.

Thu, 07/20/2017 - 15:40
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Interhemispheric disconnectivity in the sensorimotor network in bipolar disorder revealed by functional connectivity and diffusion tensor imaging analysis.

Heliyon. 2017 Jun;3(6):e00335

Authors: Ishida T, Donishi T, Iwatani J, Yamada S, Takahashi S, Ukai S, Shinosaki K, Terada M, Kaneoke Y

Abstract
BACKGROUND: Little is known regarding interhemispheric functional connectivity (FC) abnormalities via the corpus callosum in subjects with bipolar disorder (BD), which might be a key pathophysiological basis of emotional processing alterations in BD.
METHODS: We performed tract-based spatial statistics (TBSS) using diffusion tensor imaging (DTI) in 24 healthy control (HC) and 22 BD subjects. Next, we analyzed the neural networks with independent component analysis (ICA) in 32HC and 25 BD subjects using resting-state functional magnetic resonance imaging.
RESULTS: In TBSS analysis, we found reduced fractional anisotropy (FA) in the corpus callosum of BD subjects. In ICA, functional within-connectivity was reduced in two clusters in the sensorimotor network (SMN) (right and left primary somatosensory areas) of BD subjects compared with HCs. FC between the two clusters and FA values in the corpus callosum of BD subjects was significantly correlated. Further, the functional within-connectivity was related to Young Mania Rating Scale (YMRS) total scores in the right premotor area in the SMN of BD subjects.
LIMITATIONS: Almost all of our BD subjects were taking several medications which could be a confounding factor.
CONCLUSIONS: Our findings suggest that interhemispheric FC dysfunction in the SMN is associated with the impaired nerve fibers in the corpus callosum, which could be one of pathophysiological bases of emotion processing dysregulation in BD patients.

PMID: 28721394 [PubMed]

Functional network integrity presages cognitive decline in preclinical Alzheimer disease.

Thu, 07/20/2017 - 15:40
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Functional network integrity presages cognitive decline in preclinical Alzheimer disease.

Neurology. 2017 Jul 04;89(1):29-37

Authors: Buckley RF, Schultz AP, Hedden T, Papp KV, Hanseeuw BJ, Marshall G, Sepulcre J, Smith EE, Rentz DM, Johnson KA, Sperling RA, Chhatwal JP

Abstract
OBJECTIVE: To examine the utility of resting-state functional connectivity MRI (rs-fcMRI) measurements of network integrity as a predictor of future cognitive decline in preclinical Alzheimer disease (AD).
METHODS: A total of 237 clinically normal older adults (aged 63-90 years, Clinical Dementia Rating 0) underwent baseline β-amyloid (Aβ) imaging with Pittsburgh compound B PET and structural and rs-fcMRI. We identified 7 networks for analysis, including 4 cognitive networks (default, salience, dorsal attention, and frontoparietal control) and 3 noncognitive networks (primary visual, extrastriate visual, motor). Using linear and curvilinear mixed models, we used baseline connectivity in these networks to predict longitudinal changes in preclinical Alzheimer cognitive composite (PACC) performance, both alone and interacting with Aβ burden. Median neuropsychological follow-up was 3 years.
RESULTS: Baseline connectivity in the default, salience, and control networks predicted longitudinal PACC decline, unlike connectivity in the dorsal attention and all noncognitive networks. Default, salience, and control network connectivity was also synergistic with Aβ burden in predicting decline, with combined higher Aβ and lower connectivity predicting the steepest curvilinear decline in PACC performance.
CONCLUSIONS: In clinically normal older adults, lower functional connectivity predicted more rapid decline in PACC scores over time, particularly when coupled with increased Aβ burden. Among examined networks, default, salience, and control networks were the strongest predictors of rate of change in PACC scores, with the inflection point of greatest decline beyond the fourth year of follow-up. These results suggest that rs-fcMRI may be a useful predictor of early, AD-related cognitive decline in clinical research settings.

PMID: 28592457 [PubMed - indexed for MEDLINE]

The Relationship between Structural and Functional Brain Changes and Altered Emotion and Cognition in Chronic Low Back Pain: A Systematic Review of MRI and fMRI Studies.

Thu, 07/20/2017 - 03:00
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The Relationship between Structural and Functional Brain Changes and Altered Emotion and Cognition in Chronic Low Back Pain: A Systematic Review of MRI and fMRI Studies.

Clin J Pain. 2017 Jul 17;:

Authors: Ng SK, Urquhart DM, Fitzgerald PB, Cicuttini FM, Hussain SM, Fitzgibbon BM

Abstract
OBJECTIVES: Chronic low back pain (CLBP) is a major health issue, yet its underlying mechanisms remain unknown. Studies have demonstrated the importance of emotion and cognition in chronic pain, however, the relevant brain physiology in magnetic resonance imaging (MRI) studies are unclear in CLBP populations. Therefore, this review aimed to identify MRI brain changes and examine their potential relationship with emotional and cognitive processes in CLBP.
METHOD: A systematic search was conducted in 5 databases. Studies that recruited adult, chronic low back pain populations, and used brain MRI protocols were included.
RESULTS: Fifty-five studies met the inclusion criteria. Of the structural MRI studies, 10 of 15 studies found decreased gray matter and 7 of 8 studies found white matter changes in CLBP groups compared to controls. Fourteen resting-state functional MRI (fMRI) studies all reported differences between CLBP and control groups in the default mode network. Interestingly, only 3 of 10 fMRI studies observed significant differences during noxious stimulation between CLBP and control groups, while 13 of 16 studies observed significant brain activation differences in CLBP groups during various external tasks. Finally, there were 3 studies that observed a degree of recovery in functional connectivity following intervention.
DISCUSSION: The brain changes in CLBP groups were mainly observed in areas and networks important in emotion and cognition, rather than those typically associated with nociception. This supports the understanding that emotional and cognitive processes may be the core contributor to the CLBP experience, however, future studies need to explore these processes further.

PMID: 28719509 [PubMed - as supplied by publisher]

Chronic antiepileptic drug use and functional network efficiency: A functional magnetic resonance imaging study.

Thu, 07/20/2017 - 03:00
Related Articles

Chronic antiepileptic drug use and functional network efficiency: A functional magnetic resonance imaging study.

World J Radiol. 2017 Jun 28;9(6):287-294

Authors: van Veenendaal TM, IJff DM, Aldenkamp AP, Lazeron RHC, Hofman PAM, de Louw AJA, Backes WH, Jansen JFA

Abstract
AIM: To increase our insight in the neuronal mechanisms underlying cognitive side-effects of antiepileptic drug (AED) treatment.
METHODS: The relation between functional magnetic resonance-acquired brain network measures, AED use, and cognitive function was investigated. Three groups of patients with epilepsy with a different risk profile for developing cognitive side effects were included: A "low risk" category (lamotrigine or levetiracetam, n = 16), an "intermediate risk" category (carbamazepine, oxcarbazepine, phenytoin, or valproate, n = 34) and a "high risk" category (topiramate, n = 5). Brain connectivity was assessed using resting state functional magnetic resonance imaging and graph theoretical network analysis. The Computerized Visual Searching Task was used to measure central information processing speed, a common cognitive side effect of AED treatment.
RESULTS: Central information processing speed was lower in patients taking AEDs from the intermediate and high risk categories, compared with patients from the low risk category. The effect of risk category on global efficiency was significant (P < 0.05, ANCOVA), with a significantly higher global efficiency for patient from the low category compared with the high risk category (P < 0.05, post-hoc test). Risk category had no significant effect on the clustering coefficient (ANCOVA, P > 0.2). Also no significant associations between information processing speed and global efficiency or the clustering coefficient (linear regression analysis, P > 0.15) were observed.
CONCLUSION: Only the four patients taking topiramate show aberrant network measures, suggesting that alterations in functional brain network organization may be only subtle and measureable in patients with more severe cognitive side effects.

PMID: 28717415 [PubMed]

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