New resting-state fMRI related studies at PubMed

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Differentiated Regional Homogeneity in Progressive Mild Cognitive Impairment: A Study With Post Hoc Label.

Fri, 06/01/2018 - 13:40

Differentiated Regional Homogeneity in Progressive Mild Cognitive Impairment: A Study With Post Hoc Label.

Am J Alzheimers Dis Other Demen. 2018 Jan 01;:1533317518778513

Authors: Cai S, Wang Y, Kang Y, Wang H, Kim H, von Deneen KM, Huang M, Jiang Y, Huang L

Abstract
PURPOSE: Mild cognitive impairment (MCI) is considered to be the clinical transition stage between patients with cognitively intact geriatrics and Alzheimer's disease (AD). When observed longitudinally, however, a certain proportion of patients with MCI are expected to revert to a cognitively intact state (MCI_R) while others either remain in the MCI state (MCI_S) or deteriorate into AD (MCI_P). It is worthwhile to investigate the divergence in the brain activities of these MCI groups with different post hoc labels.
METHODS: In this study, we employed the regional homogeneity (ReHo) measure to explore the characteristics of local brain activity in these MCI groups.
RESULTS: Compared to age-matched normal controls, our results exhibited that (1) in MCI_R group, ReHo index showed an increase in the left insula and a decrease in the left superior temporal gyrus; (2) in MCI_S group, ReHo index increased in the left orbital part of the inferior frontal gyrus (IFG_orb) and decreased in the left inferior parietal lobe; and (3) in MCI_P group, ReHo index elevated in the left IFG_orb and decreased in the left putamen.
CONCLUSIONS: The distinct ReHo changes in the individual MCI groups indicated a potential evidence for differentially active interventions for a specific patient with MCI.

PMID: 29847992 [PubMed - as supplied by publisher]

Alterations in striato-thalamo-pallidal intrinsic functional connectivity as a prodrome of Parkinson's disease.

Fri, 06/01/2018 - 13:40
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Alterations in striato-thalamo-pallidal intrinsic functional connectivity as a prodrome of Parkinson's disease.

Neuroimage Clin. 2017;16:313-318

Authors: Dayan E, Browner N

Abstract
Although the diagnosis of Parkinson's disease (PD) remains anchored around the cardinal motor symptoms of bradykinesia, rest tremor, rigidity and postural instability, it is becoming increasingly clear that the clinical phase of the disease is preceded by a long period of neurodegeneration, which is not readily evident in terms of motor dysfunction. The neurobiological mechanisms that underpin this prodromal phase of PD remain poorly understood. Based on converging evidence of basal ganglia (BG) dysfunction in early PD, we set out to establish whether the prodromal phase of the disease is characterized by alterations in functional communication within the input and output structures of the BG. We analyzed resting-state functional MRI data collected from patients with REM sleep behavior disorder (RBD) and/or hyposmia, two of the strongest markers of prodromal PD, in comparison to age-matched controls. Relative to controls, subjects in the prodromal group showed reduced intra- and interhemispheric functional connectivity in a striato-thalamo-pallidal network. Functional connectivity alterations were restricted to the BG and did not extend to functional connections with the cortex. The data suggest that local interactions between input and output BG structures may be disrupted already in the prodromal phase of PD.

PMID: 28856094 [PubMed - indexed for MEDLINE]

Aberrant topological organization of the functional brain network associated with prior overt hepatic encephalopathy in cirrhotic patients.

Thu, 05/31/2018 - 19:00

Aberrant topological organization of the functional brain network associated with prior overt hepatic encephalopathy in cirrhotic patients.

Brain Imaging Behav. 2018 May 30;:

Authors: Chen HJ, Chen QF, Yang ZT, Shi HB

Abstract
A higher risk of cognitive impairments has been found after an overt hepatic encephalopathy (OHE) episode in cirrhotic patients. We investigated the effect of prior OHE episodes on the topological organization of the functional brain network and its association with the relevant cognitive impairments. Resting-state functional MRI data were acquired from 41 cirrhotic patients (19 with prior OHE (Prior-OHE) and 22 without (Non-Prior-OHE)) and 21 healthy controls (HC). A Psychometric Hepatic Encephalopathy Score (PHES) assessed cognition. The whole-brain functional network was constructed by thresholding functional correlation matrices of 90 brain regions (derived from the Automated Anatomic Labeling atlas). The topological properties of the brain network, including small-worldness, network efficiency, and nodal efficiency, were examined using graph theory-based analysis. Globally, the Prior-OHE group had a significantly decreased clustering coefficient and local efficiency, compared with the controls. Locally, the nodal efficiency in the bilateral medial superior frontal gyrus and the right postcentral gyrus decreased in the Prior-OHE group, while the nodal efficiency in the bilateral anterior cingulate/paracingulate gyri and right superior parietal gyrus increased in the Prior-OHE group. The alterations of global and regional network parameters progressed from Non-Prior-OHE to Prior-OHE and the clustering coefficient and local efficiency values were significantly correlated with PHES results. In conclusion, cirrhosis leads to the reduction of brain functional network efficiency, which could be aggravated by a prior OHE episode. Aberrant topological organization of the functional brain network may contribute to a higher risk of cognitive impairments in Prior-OHE patients.

PMID: 29846883 [PubMed - as supplied by publisher]

Disrupted functional connectivity in primary progressive apraxia of speech.

Thu, 05/31/2018 - 19:00
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Disrupted functional connectivity in primary progressive apraxia of speech.

Neuroimage Clin. 2018;18:617-629

Authors: Botha H, Utianski RL, Whitwell JL, Duffy JR, Clark HM, Strand EA, Machulda MM, Tosakulwong N, Knopman DS, Petersen RC, Jack CR, Josephs KA, Jones DT

Abstract
Apraxia of speech is a motor speech disorder thought to result from impaired planning or programming of articulatory movements. It can be the initial or only manifestation of a degenerative disease, termed primary progressive apraxia of speech (PPAOS). The aim of this study was to use task-free functional magnetic resonance imaging (fMRI) to assess large-scale brain network pathophysiology in PPAOS. Twenty-two PPAOS participants were identified from a prospective cohort of degenerative speech and language disorders patients. All participants had a comprehensive, standardized evaluation including an evaluation by a speech-language pathologist, examination by a behavioral neurologist and a multimodal imaging protocol which included a task-free fMRI sequence. PPAOS participants were age and sex matched to amyloid-negative, cognitively normal participants with a 1:2 ratio. We chose a set of hypothesis driven, predefined intrinsic connectivity networks (ICNs) from a large, out of sample independent component analysis and then used them to initialize a spatiotemporal dual regression to estimate participant level connectivity within these ICNs. Specifically, we evaluated connectivity within the speech and language, face and hand sensorimotor, left working memory, salience, superior parietal, supramarginal, insular and deep gray ICNs in a multivariate manner. The spatial maps for each ICN were then compared between PPAOS and control participants. We used clinical measures of apraxia of speech severity to assess for clinical-connectivity correlations for regions found to differ between PPAOS and control participants. Compared to controls, PPAOS participants had reduced connectivity of the right supplementary motor area and left posterior temporal gyrus to the rest of the speech and language ICN. The connectivity of the right supplementary motor area correlated negatively with an articulatory error score. PPAOS participants also had reduced connectivity of the left supplementary motor area to the face sensorimotor ICN, between the left lateral prefrontal cortex and the salience ICN and between the left temporal-occipital junction and the left working memory ICN. The latter connectivity correlated with the apraxia of speech severity rating scale, although the finding did not survive correction for multiple comparisons. Increased connectivity was noted in PPAOS participants between the dorsal posterior cingulate and the left working memory ICN. Our results support the importance of the supplementary motor area in the pathophysiology of PPAOS, which appears to be disconnected from speech and language regions. Supplementary motor area connectivity may serve as a biomarker of degenerative apraxia of speech severity.

PMID: 29845010 [PubMed - in process]

Decreased functional connectivity in the fronto-parietal network in children with mood disorders compared to children with dyslexia during rest: An fMRI study.

Thu, 05/31/2018 - 19:00
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Decreased functional connectivity in the fronto-parietal network in children with mood disorders compared to children with dyslexia during rest: An fMRI study.

Neuroimage Clin. 2018;18:582-590

Authors: Horowitz-Kraus T, Woodburn M, Rajagopal A, Versace AL, Kowatch RA, Bertocci MA, Bebko G, Almeida JRC, Perlman SB, Travis MJ, Gill MK, Bonar L, Schirda C, Diwadkar VA, Sunshine JL, Birmaher B, Axelson D, Gerry Taylor H, Horwitz SM, Frazier T, Eugene Arnold L, Fristad MA, Youngstrom EA, Findling RL, Phillips ML, Holland SK

Abstract
Background: The DSM-5 separates the diagnostic criteria for mood and behavioral disorders. Both types of disorders share neurocognitive deficits of executive function and reading difficulties in childhood. Children with dyslexia also have executive function deficits, revealing a role of executive function circuitry in reading. The aim of the current study is to determine whether there is a significant relationship of functional connectivity within the fronto-parietal and cingulo-opercular cognitive control networks to reading measures for children with mood disorders, behavioral disorders, dyslexia, and healthy controls (HC).
Method: Behavioral reading measures of phonological awareness, decoding, and orthography were collected. Resting state fMRI data were collected, preprocessed, and then analyzed for functional connectivity. Differences in the reading measures were tested for significance among the groups. Global efficiency (GE) measures were also tested for correlation with reading measures in 40 children with various disorders and 17 HCs.
Results: Significant differences were found between the four groups on all reading measures. Relative to HCs and children with mood disorders or behavior disorders, children with dyslexia as a primary diagnosis scored significantly lower on all three reading measures. Children with mood disorders scored significantly lower than controls on a test of phonological awareness. Phonological awareness deficits correlated with reduced resting state functional connectivity MRI (rsfcMRI) in the cingulo-opercular network for children with dyslexia. A significant difference was also found in fronto-parietal global efficiency in children with mood disorders relative to the other three groups. We also found a significant difference in cingulo-opercular global efficiency in children with mood disorders relative to the Dyslexia and Control groups. However, none of these differences correlate significantly with reading measures.
Conclusions/significance: Reading difficulties involve abnormalities in different cognitive control networks in children with dyslexia compared to children with mood disorders. Findings of the current study suggest increased functional connectivity of one cognitive control network may compensate for reduced functional connectivity in the other network in children with mood disorders. These findings provide guidance to clinical professionals for design of interventions tailored for children suffering from reading difficulties originating from different pathologies.

PMID: 29845006 [PubMed - in process]

Decoupling of Local Metabolic Activity and Functional Connectivity Links to Amyloid in Alzheimer's Disease.

Thu, 05/31/2018 - 19:00
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Decoupling of Local Metabolic Activity and Functional Connectivity Links to Amyloid in Alzheimer's Disease.

J Alzheimers Dis. 2018 May 19;:

Authors: Scherr M, Pasquini L, Benson G, Nuttall R, Gruber M, Neitzel J, Brandl F, Sorg C, Alzheimer’s Disease Neuroimaging Initiative

Abstract
BACKGROUND: Both ongoing local metabolic activity (LMA) and corresponding functional connectivity (FC) with remote brain regions are progressively impaired in Alzheimer's disease (AD), particularly in the posterior default mode network (pDMN); however, it is unknown how these impairments interact. It is well known that decreasing mean synaptic activity of a region, i.e., decreasing LMA, reduces the region's sensitivity to afferent input from other regions, i.e., FC.
OBJECTIVE: We hypothesized progressive decoupling between LMA and FC in AD, which is linked to amyloid-β pathology (Aβ).
METHODS: Healthy adults (n=20) and Aβ+patients without memory impairment (n=9), early MCI (n=21), late MCI (n=18) and AD (n=22) were assessed by resting-state fMRI, FDG-PET, and AV-45-PET to measure FC, LMA, and Aβ of the pDMN. Coupling between LMA and FC (rLA/FC) was estimated by voxelwise correlation.
RESULTS: RLMA/FC decreased with disease severity (F=20.09, p<0.001). This decrease was specifically associated with pDMN Aβ (r=-0.273, p=0.029) but not global Aβ (r=-0.112, p=0.378) and with the impact of Aβ on FC (i.e., rAβ/FC,r=-0.339; p=0.006). In multiple regression models rLMA/FC was also associated with memory impairment, reduced cognitive speed and flexibility, outperforming global Aβ, pDMN Aβ, pDMN LMA, and pDMN FC, respectively.
CONCLUSION: Results demonstrate increasing decoupling of LMA from its FC in AD. Data suggest that decoupling is driven by local Aβ and contributes to memory decline.

PMID: 29843243 [PubMed - as supplied by publisher]

Intrinsic functional connectivity variance and state-specific under-connectivity in autism.

Thu, 05/31/2018 - 19:00
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Intrinsic functional connectivity variance and state-specific under-connectivity in autism.

Hum Brain Mapp. 2017 Nov;38(11):5740-5755

Authors: Chen H, Nomi JS, Uddin LQ, Duan X, Chen H

Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental condition associated with altered brain connectivity. Previous neuroimaging research demonstrates inconsistent results, particularly in studies of functional connectivity in ASD. Typically, these inconsistent findings are results of studies using static measures of resting-state functional connectivity. Recent work has demonstrated that functional brain connections are dynamic, suggesting that static connectivity metrics fail to capture nuanced time-varying properties of functional connections in the brain. Here we used a dynamic functional connectivity approach to examine the differences in the strength and variance of dynamic functional connections between individuals with ASD and healthy controls (HCs). The variance of dynamic functional connections was defined as the respective standard deviations of the dynamic functional connectivity strength across time. We utilized a large multicenter dataset of 507 male subjects (209 with ASD and 298 HC, from 6 to 36 years old) from the Autism Brain Imaging Data Exchange (ABIDE) to identify six distinct whole-brain dynamic functional connectivity states. Analyses demonstrated greater variance of widespread long-range dynamic functional connections in ASD (P < 0.05, NBS method) and weaker dynamic functional connections in ASD (P < 0.05, NBS method) within specific whole-brain connectivity states. Hypervariant dynamic connections were also characterized by weaker connectivity strength in ASD compared with HC. Increased variance of dynamic functional connections was also related to ASD symptom severity (ADOS total score) (P < 0.05), and was most prominent in connections related to the medial superior frontal gyrus and temporal pole. These results demonstrate that greater intraindividual dynamic variance is a potential biomarker of ASD. Hum Brain Mapp 38:5740-5755, 2017. © 2017 Wiley Periodicals, Inc.

PMID: 28792117 [PubMed - indexed for MEDLINE]

Enhanced estimations of post-stroke aphasia severity using stacked multimodal predictions.

Thu, 05/31/2018 - 19:00
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Enhanced estimations of post-stroke aphasia severity using stacked multimodal predictions.

Hum Brain Mapp. 2017 Nov;38(11):5603-5615

Authors: Pustina D, Coslett HB, Ungar L, Faseyitan OK, Medaglia JD, Avants B, Schwartz MF

Abstract
The severity of post-stroke aphasia and the potential for recovery are highly variable and difficult to predict. Evidence suggests that optimal estimation of aphasia severity requires the integration of multiple neuroimaging modalities and the adoption of new methods that can detect multivariate brain-behavior relationships. We created and tested a multimodal framework that relies on three information sources (lesion maps, structural connectivity, and functional connectivity) to create an array of unimodal predictions which are then fed into a final model that creates "stacked multimodal predictions" (STAMP). Crossvalidated predictions of four aphasia scores (picture naming, sentence repetition, sentence comprehension, and overall aphasia severity) were obtained from 53 left hemispheric chronic stroke patients (age: 57.1 ± 12.3 yrs, post-stroke interval: 20 months, 25 female). Results showed accurate predictions for all four aphasia scores (correlation true vs. predicted: r = 0.79-0.88). The accuracy was slightly smaller but yet significant (r = 0.66) in a full split crossvalidation with each patient considered as new. Critically, multimodal predictions produced more accurate results that any single modality alone. Topological maps of the brain regions involved in the prediction were recovered and compared with traditional voxel-based lesion-to-symptom maps, revealing high spatial congruency. These results suggest that neuroimaging modalities carry complementary information potentially useful for the prediction of aphasia scores. More broadly, this study shows that the translation of neuroimaging findings into clinically useful tools calls for a shift in perspective from unimodal to multimodal neuroimaging, from univariate to multivariate methods, from linear to nonlinear models, and, conceptually, from inferential to predictive brain mapping. Hum Brain Mapp 38:5603-5615, 2017. © 2017 Wiley Periodicals, Inc.

PMID: 28782862 [PubMed - indexed for MEDLINE]

Seizure Control and Memory Impairment Are Related to Disrupted Brain Functional Integration in Temporal Lobe Epilepsy.

Thu, 05/31/2018 - 19:00
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Seizure Control and Memory Impairment Are Related to Disrupted Brain Functional Integration in Temporal Lobe Epilepsy.

J Neuropsychiatry Clin Neurosci. 2017;29(4):343-350

Authors: Park CH, Choi YS, Jung AR, Chung HK, Kim HJ, Yoo JH, Lee HW

Abstract
Brain functional integration can be disrupted in patients with temporal lobe epilepsy (TLE), but the clinical relevance of this disruption is not completely understood. The authors hypothesized that disrupted functional integration over brain regions remote from, as well as adjacent to, the seizure focus could be related to clinical severity in terms of seizure control and memory impairment. Using resting-state functional MRI data acquired from 48 TLE patients and 45 healthy controls, the authors mapped functional brain networks and assessed changes in a network parameter of brain functional integration, efficiency, to examine the distribution of disrupted functional integration within and between brain regions. The authors assessed whether the extent of altered efficiency was influenced by seizure control status and whether the degree of altered efficiency was associated with the severity of memory impairment. Alterations in the efficiency were observed primarily near the subcortical region ipsilateral to the seizure focus in TLE patients. The extent of regional involvement was greater in patients with poor seizure control: it reached the frontal, temporal, occipital, and insular cortices in TLE patients with poor seizure control, whereas it was limited to the limbic and parietal cortices in TLE patients with good seizure control. Furthermore, TLE patients with poor seizure control experienced more severe memory impairment, and this was associated with lower efficiency in the brain regions with altered efficiency. These findings indicate that the distribution of disrupted brain functional integration is clinically relevant, as it is associated with seizure control status and comorbid memory impairment.

PMID: 28449635 [PubMed - indexed for MEDLINE]

Differentiated Effective Connectivity Patterns of the Executive Control Network in Progressive MCI: A Potential Biomarker for Predicting AD.

Thu, 05/31/2018 - 19:00
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Differentiated Effective Connectivity Patterns of the Executive Control Network in Progressive MCI: A Potential Biomarker for Predicting AD.

Curr Alzheimer Res. 2017;14(9):937-950

Authors: Cai S, Peng Y, Chong T, Zhang Y, von Deneen KM, Huang L, Alzheimer's Disease Neuroimaging Initiative

Abstract
OBJECTIVE: Mild cognitive impairment (MCI) is often a transitional state between normal aging and Alzheimer's disease (AD). When observed longitudinally, some MCI patients convert to AD, while a considerable portion either remains MCI or revert to a normal functioning state. This divergence has provided some enlightenment on a potential biomarker to be represented in the resting state brain activities of MCI patients with different post-hoc labels. Recent studies have shown impaired executive functions, other than typically explicated memory impairment with AD/MCI patients. This observation raises the question that whether or not the executive control network (ECN) was impaired, which pivotally supports the central executive functions. Given the fact that effective connectivity is a sufficient index in detecting resting brain abnormalities in AD/MCI, the current study specifically asks a question whether the effective connectivity patterns are differentiated in MCI patients with different post-hoc labels.
METHODS: We divided the MCI subjects into three groups depending on their progressive state obtained longitudinally: 1) 15 MCI-R subjects: MCI reverted to the normal functioning state and stabilized to the normal state in 24 months; 2) 35 MCI-S subjects: MCI patients maintained this disease in a stable state for 24 months; 3) 22 MCI-P subjects: MCI progressed to AD and stabilized to AD in 24 months, and 4) 39 age-matched normal control subjects (NC). We conducted a Granger causality analysis after identifying the core nodes of ECN in all of the subjects using Independent Component Analysis. Our findings revealed that different MCI groups presented different effective connectivity patterns within the ECN compared to the NC group. Specifically, (1) dorsolateral prefrontal cortex (dLPFC) and medial prefrontal cortex (mPFC) were the core nodes in the ECN network that exhibited different connecting patterns; (2) an effective connection circuit "R.dLPFC→ right caudate→ left thalamus→R.dLPFC" in the ECN showed different levels of damage; and (3) there were four pathways between the R.dLPFC and L.LP, and these four pathways were also different.
RESULTS: Our results would help to understand the potential central mechanism of MCI patients. The differentiated effective connectivity of ECN may serve as a potential biomarker for early detection of AD, which may also provide a reference for clinical researchers to manipulate active but distinctive interventions for MCI patients who have different risks.

PMID: 28290245 [PubMed - indexed for MEDLINE]

Resting-state functional connectivity in medication-naïve schizophrenia patients with and without auditory verbal hallucinations: A preliminary report.

Thu, 05/31/2018 - 19:00
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Resting-state functional connectivity in medication-naïve schizophrenia patients with and without auditory verbal hallucinations: A preliminary report.

Schizophr Res. 2017 Oct;188:75-81

Authors: Chang X, Collin G, Xi Y, Cui L, Scholtens LH, Sommer IE, Wang H, Yin H, Kahn RS, van den Heuvel MP

Abstract
Auditory verbal hallucinations (AVH) are a cardinal feature of schizophrenia that has been associated with activation in language processing areas, in concert with higher-order cognitive brain networks. It remains to be determined whether, and if so how, the functional dynamics between these brain regions contributes to the emergence of AVH. The current study recruited 36 first-episode medication-naïve schizophrenia patients, including 18 patients with AVH, 18 patients free of AVH and 18 controls matched on age, gender and level of education. Resting-state functional MRI images were acquired for every subject and used to map functional brain connectivity. We compared functional connectivity in 18 bilateral regions of interest implicated by previous AVH studies among the three subject groups, with the aim of detecting patterns of dysconnectivity unique to or most pronounced in AVH patients. Results showed that AVH patients are characterized by dysconnectivity in neural circuitry involving the anterior cingulate cortex, insular cortex and language-related regions, comparing with both controls and non-AVH patients. Current findings suggest that abnormality in speech-sensitive areas and their functional cooperation with cortical regions involving in source monitoring and salience detection functions may contribute to the occurrence of AVH.

PMID: 28130005 [PubMed - indexed for MEDLINE]

Cerebral activation effects of acupuncture at Yanglinquan(GB34) point acquired using resting-state fMRI.

Tue, 05/29/2018 - 23:00
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Cerebral activation effects of acupuncture at Yanglinquan(GB34) point acquired using resting-state fMRI.

Comput Med Imaging Graph. 2018 Apr 21;67:55-58

Authors: Liu L, Chen S, Zeng D, Li H, Shi C, Zhang L

Abstract
OBJECTIVE: To explore the central mechanism of acupuncture points for regional homogeneity(ReHo) of resting state in brain function after acupuncture at GB34.
METHODS: Ten healthy volunteers were enrolled, which included 4 males and 6 females, aged 20-34 years old with median age of 23. The GE Signa HDxt 3.0 T magnetic resonance imaging were performed before (control group) and after acupuncture at GB34, and differences of different brain ReHo of 2 groups by statistical parametric mapping (SPM8) software and ReHo data processing methods were analyzed. The statistically different brain regions were obtained by false discovery rate corrected (FDR-Corrected).
RESULTS: Compared with control group, the anterior cingulated gyrus, left temporal gyrus, right inferior parietal lobule, right frontal gyrus were enhanced ReHo after acupuncture at GB34. The left thalamus, right insular cortex, left inferior frontal gyrus, right anterior cingulate were decreased ReHo after acupuncture at GB34.
CONCLUSION: It is demonstrated that the signal synchronization change ReHo in different brain regions including cognitive, motor, default network, limbic system and other parts of encephalic region after acupuncture at GB34, suggesting that the central mechanism of acupuncture at GB34 is the result of all levels of the combined effects of brain networks.

PMID: 29800886 [PubMed - as supplied by publisher]

Cerebro-Cerebellar Functional Connectivity is Associated with Cerebellar Excitation-Inhibition Balance in Autism Spectrum Disorder.

Tue, 05/29/2018 - 23:00
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Cerebro-Cerebellar Functional Connectivity is Associated with Cerebellar Excitation-Inhibition Balance in Autism Spectrum Disorder.

J Autism Dev Disord. 2018 May 23;:

Authors: Hegarty JP, Weber DJ, Cirstea CM, Beversdorf DQ

Abstract
Atypical functional connectivity (FC) and an imbalance of excitation-to-inhibition (E/I) have been previously reported in cerebro-cerebellar circuits in autism spectrum disorder (ASD). The current investigation used resting state fMRI and proton magnetic resonance spectroscopy (1H-MRS) to examine the relationships between E/I (glutamate + glutamine/GABA) and FC of the dorsolateral prefrontal cortex and posterolateral cerebellar hemisphere from 14 adolescents/adults with ASD and 12 age/sex/IQ-matched controls. In this pilot sample, cerebro-cerebellar FC was positively associated with cerebellar E/I and listening comprehension abilities in individuals with ASD but not controls. Additionally, a subgroup of individuals with ASD and low FC (n = 5) exhibited reduced E/I and impaired listening comprehension. Thus, altered functional coherence of cerebro-cerebellar circuits in ASD may be related with a cerebellar E/I imbalance.

PMID: 29796960 [PubMed - as supplied by publisher]

Changes in Resting-State Connectivity following Melody-Based Therapy in a Patient with Aphasia.

Tue, 05/29/2018 - 23:00
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Changes in Resting-State Connectivity following Melody-Based Therapy in a Patient with Aphasia.

Neural Plast. 2018;2018:6214095

Authors: Bitan T, Simic T, Saverino C, Jones C, Glazer J, Collela B, Wiseman-Hakes C, Green R, Rochon E

Abstract
Melody-based treatments for patients with aphasia rely on the notion of preserved musical abilities in the RH, following left hemisphere damage. However, despite evidence for their effectiveness, the role of the RH is still an open question. We measured changes in resting-state functional connectivity following melody-based intervention, to identify lateralization of treatment-related changes. A patient with aphasia due to left frontal and temporal hemorrhages following traumatic brain injuries (TBI) more than three years earlier received 48 sessions of melody-based intervention. Behavioral measures improved and were maintained at the 8-week posttreatment follow-up. Resting-state fMRI data collected before and after treatment showed an increase in connectivity between motor speech control areas (bilateral supplementary motor areas and insulae) and RH language areas (inferior frontal gyrus pars triangularis and pars opercularis). This change, which was specific for the RH, was greater than changes in a baseline interval measured before treatment. No changes in RH connectivity were found in a matched control TBI patient scanned at the same intervals. These results are compatible with a compensatory role for RH language areas following melody-based intervention. They further suggest that this therapy intervenes at the level of the interface between language areas and speech motor control areas necessary for language production.

PMID: 29796017 [PubMed - in process]

Synchronization within, and interactions between, the default mode and dorsal attention networks in relapsing-remitting multiple sclerosis.

Tue, 05/29/2018 - 23:00
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Synchronization within, and interactions between, the default mode and dorsal attention networks in relapsing-remitting multiple sclerosis.

Neuropsychiatr Dis Treat. 2018;14:1241-1252

Authors: Huang M, Zhou F, Wu L, Wang B, Wan H, Li F, Zeng X, Gong H

Abstract
Background and purpose: The effects of the interactions between the default mode network (DMN) and the dorsal attention network (DAN), which present anticorrelated behaviors, in relapsing-remitting multiple sclerosis (RRMS) are poorly understood. This study used resting-state functional connectivity (FC) and the Granger causality test (GCT) to examine changes in the undirected and effective functional network connectivity (FNC) between the two networks during the remitting phase in RRMS patients.
Patients and methods: Thirty-three patients experiencing a clinically diagnosed remitting phase of RRMS and 33 well-matched healthy control subjects participated in this study. First, an independent component (IC) analysis was performed to preprocess the functional magnetic resonance imaging data and select resting-state networks. Then, an FNC analysis and the GCT were combined to examine the temporal correlations between the ICs of the DMN and DAN and to identify correlations with clinical markers.
Results: Compared with the healthy subjects, the RRMS patients in the remitting phase showed the following: 1) significantly decreased FC within the DAN in the postcentral gyrus and decreased FC within the DMN in several regions except the parahippocampal gyrus, where increased FC was observed; 2) a relatively stable interaction between the two anticorrelated networks as well as a driving connectivity from the DAN to DMN (IC15); and 3) significantly positive correlations between the connectivity coefficient of the right superior temporal gyrus and the Modified Fatigue Impact Scale score (ρ = 0.379, p = 0.036).
Conclusion: Adaptive mechanisms that maintain stable interactions might occur between the DMN and DAN during the remitting phase in RRMS patients.

PMID: 29795982 [PubMed]

Disrupted interhemispheric functional connectivity in chronic insomnia disorder: a resting-state fMRI study.

Tue, 05/29/2018 - 23:00
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Disrupted interhemispheric functional connectivity in chronic insomnia disorder: a resting-state fMRI study.

Neuropsychiatr Dis Treat. 2018;14:1229-1240

Authors: Zhou F, Zhao Y, Huang M, Zeng X, Wang B, Gong H

Abstract
Background: Abnormalities in both cerebral structure and intrinsic activity have been increasingly reported in patients with chronic insomnia disorder (CID). However, the inter-hemispheric integration function in CID is still not well understood. Functional homotopy reflects an essential aspect of the intrinsic functional architecture involved in interhemispheric coordination.
Methods: In this study, voxel-mirrored homotopic connectivity (VMHC) was used to analyze the patterns of interhemispheric intrinsic functional connectivity in patients with CID (n=29).
Results: Reduced homotopic connectivity was observed in the middle occipital/posterior middle temporal gyrus in CID patients relative to control subjects. Further analyses demonstrated different insomnia-related heterotopic connectivity patterns in the right and left middle occipital/posterior middle temporal gyrus. Furthermore, within the CID group, the connectivity coefficient within the connectivity network of the middle occipital/posterior middle temporal gyrus was associated with anxiety measures.
Conclusion: Negative significant findings of group differences were found in terms of both the local gray matter density and fractional anisotropy of the white matter skeletal measures in this study; this structural finding, together with the results of VMHC, suggested that disruptions in the intrinsic functional architecture of interhemispheric communication associated with CID can be observed in the absence of detectable microstructural or local morphometric changes in white and gray matter.

PMID: 29795981 [PubMed]

Identification of alterations associated with age in the clustering structure of functional brain networks.

Tue, 05/29/2018 - 23:00
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Identification of alterations associated with age in the clustering structure of functional brain networks.

PLoS One. 2018;13(5):e0195906

Authors: Guzman GEC, Sato JR, Vidal MC, Fujita A

Abstract
Initial studies using resting-state functional magnetic resonance imaging on the trajectories of the brain network from childhood to adulthood found evidence of functional integration and segregation over time. The comprehension of how healthy individuals' functional integration and segregation occur is crucial to enhance our understanding of possible deviations that may lead to brain disorders. Recent approaches have focused on the framework wherein the functional brain network is organized into spatially distributed modules that have been associated with specific cognitive functions. Here, we tested the hypothesis that the clustering structure of brain networks evolves during development. To address this hypothesis, we defined a measure of how well a brain region is clustered (network fitness index), and developed a method to evaluate its association with age. Then, we applied this method to a functional magnetic resonance imaging data set composed of 397 males under 31 years of age collected as part of the Autism Brain Imaging Data Exchange Consortium. As results, we identified two brain regions for which the clustering change over time, namely, the left middle temporal gyrus and the left putamen. Since the network fitness index is associated with both integration and segregation, our finding suggests that the identified brain region plays a role in the development of brain systems.

PMID: 29795565 [PubMed - in process]

fMRI classification method with multiple feature fusion based on minimum spanning tree analysis.

Fri, 05/25/2018 - 18:40
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fMRI classification method with multiple feature fusion based on minimum spanning tree analysis.

Psychiatry Res Neuroimaging. 2018 May 21;277:14-27

Authors: Guo H, Yan P, Cheng C, Li Y, Chen J, Xu Y, Xiang J

Abstract
Resting state functional brain networks have been widely studied in brain disease research. Conventional network analysis methods are hampered by differences in network size, density and normalization. Minimum spanning tree (MST) analysis has been recently suggested to ameliorate these limitations. Moreover, common MST analysis methods involve calculating quantifiable attributes and selecting these attributes as features in the classification. However, a disadvantage of these methods is that information about the topology of the network is not fully considered, limiting further improvement of classification performance. To address this issue, we propose a novel method combining brain region and subgraph features for classification, utilizing two feature types to quantify two properties of the network. We experimentally validated our proposed method using a major depressive disorder (MDD) patient dataset. The results indicated that MSTs of MDD patients were more similar to random networks and exhibited significant differences in certain regions involved in the limbic-cortical-striatal-pallidal-thalamic (LCSPT) circuit, which is considered to be a major pathological circuit of depression. Moreover, we demonstrated that this novel classification method could effectively improve classification accuracy and provide better interpretability. Overall, the current study demonstrated that different forms of feature representation provide complementary information.

PMID: 29793077 [PubMed - as supplied by publisher]

White Matter Hyperintensity Load Modulates Brain Morphometry and Brain Connectivity in Healthy Adults: A Neuroplastic Mechanism?

Fri, 05/25/2018 - 18:40
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White Matter Hyperintensity Load Modulates Brain Morphometry and Brain Connectivity in Healthy Adults: A Neuroplastic Mechanism?

Neural Plast. 2017;2017:4050536

Authors: De Marco M, Manca R, Mitolo M, Venneri A

Abstract
White matter hyperintensities (WMHs) are acquired lesions that accumulate and disrupt neuron-to-neuron connectivity. We tested the associations between WMH load and (1) regional grey matter volumes and (2) functional connectivity of resting-state networks, in a sample of 51 healthy adults. Specifically, we focused on the positive associations (more damage, more volume/connectivity) to investigate a potential route of adaptive plasticity. WMHs were quantified with an automated procedure. Voxel-based morphometry was carried out to model grey matter. An independent component analysis was run to extract the anterior and posterior default-mode network, the salience network, the left and right frontoparietal networks, and the visual network. Each model was corrected for age, global levels of atrophy, and indices of brain and cognitive reserve. Positive associations were found with morphometry and functional connectivity of the anterior default-mode network and salience network. Within the anterior default-mode network, an association was found in the left mediotemporal-limbic complex. Within the salience network, an association was found in the right parietal cortex. The findings support the suggestion that, even in the absence of overt disease, the brain actuates a compensatory (neuroplastic) response to the accumulation of WMH, leading to increases in regional grey matter and modified functional connectivity.

PMID: 28845309 [PubMed - indexed for MEDLINE]

The Temporal Pattern of a Lesion Modulates the Functional Network Topology of Remote Brain Regions.

Fri, 05/25/2018 - 18:40
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The Temporal Pattern of a Lesion Modulates the Functional Network Topology of Remote Brain Regions.

Neural Plast. 2017;2017:3530723

Authors: De Baene W, Rutten GJM, Sitskoorn MM

Abstract
Focal brain lesions can alter the morphology and function of remote brain areas. When the damage is inflicted more slowly, the functional compensation by and structural reshaping of these areas seem to be more effective. It remains unclear, however, whether the momentum of lesion development also modulates the functional network topology of the remote brain areas. In this study, we compared resting-state functional connectivity data of patients with a slowly growing low-grade glioma (LGG) with that of patients with a faster-growing high-grade glioma (HGG). Using graph theory, we examined whether the tumour growth velocity modulated the functional network topology of remote areas, more specifically of the hemisphere contralateral to the lesion. We observed that the contralesional network topology characteristics differed between patient groups. Based only on the connectivity of the hemisphere contralateral to the lesion, patients could be classified in the correct tumour-grade group with 70% accuracy. Additionally, LGG patients showed smaller contralesional intramodular connectivity, smaller contralesional ratio between intra- and intermodular connectivity, and larger contralesional intermodular connectivity than HGG patients. These results suggest that, in the hemisphere contralateral to the lesion, there is a lower capacity for local, specialized information processing coupled to a higher capacity for distributed information processing in LGG patients. These results underline the utility of a network perspective in evaluating effects of focal brain injury.

PMID: 28845308 [PubMed - indexed for MEDLINE]

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