New resting-state fMRI related studies at PubMed

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Dynamic spatiotemporal variability of alpha-BOLD relationships during the resting-state and task-evoked responses.

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Dynamic spatiotemporal variability of alpha-BOLD relationships during the resting-state and task-evoked responses.

Neuroimage. 2017 Apr 25;:

Authors: Mayhew SD, Bagshaw AP

Abstract
Accurate characterization of the spatiotemporal relationship between two of the most prominent neuroimaging measures of neuronal activity, the 8-13Hz, occipito-parietal EEG alpha oscillation and the BOLD fMRI signal, must encompass the intrinsically dynamic nature of both alpha power and brain function. Here, during the eyes-open resting state, we use a 16s sliding-window analysis and demonstrate that the mean spatial network of dynamic alpha-BOLD correlations is highly comparable to the static network calculated over six minutes. However, alpha-BOLD correlations showed substantial spatiotemporal variability within-subjects and passed through many different configurations such that the static network was fully represented in only ~10% of 16s epochs, with visual and parietal regions (coherent on average) often opposingly correlated with each other or with alpha. We find that the common assumption of static-alpha BOLD correlations greatly oversimplifies temporal variation in brain network dynamics. Fluctuations in alpha-BOLD coupling significantly depended upon the instantaneous amplitude of alpha power, and primary and lateral visual areas were most strongly negatively correlated with alpha during different alpha power states, possibly suggesting the action of multiple alpha mechanisms. Dynamic alpha-BOLD correlations could not be explained by eye-blinks/movements, head motion or non-neuronal physiological variability. Individual's mean alpha power and frequency were found to contribute to between-subject variability in alpha-BOLD correlations. Additionally, application to a visual stimulation dataset showed that dynamic alpha-BOLD correlations provided functional information pertaining to the brain's response to stimulation by exhibiting spatiotemporal fluctuations related to variability in the trial-by-trial BOLD response magnitude. Significantly weaker visual alpha-BOLD correlations were found both preceding and following small amplitude BOLD response trials compared to large response trials.

PMID: 28454820 [PubMed - as supplied by publisher]

From the neurobiological basis of comorbid alcohol dependence and depression to psychological treatment strategies: study protocol of a randomized controlled trial.

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From the neurobiological basis of comorbid alcohol dependence and depression to psychological treatment strategies: study protocol of a randomized controlled trial.

BMC Psychiatry. 2017 Apr 28;17(1):153

Authors: Becker A, Ehret AM, Kirsch P

Abstract
BACKGROUND: Alcohol use disorder and depression occur commonly in the community. Even though this high-prevalence comorbidity is associated with poorer posttreatment outcomes and greater utilization of costly treatment services, existing treatment trials often exclude patients with comorbid depressive and alcohol use disorders. Past research suggests that symptoms such as craving and anhedonia might be associated with alterations within the reward circuit, while emotion regulation deficits are related to disruptions within the default mode network. The aim of this clinical neuroimaging study is to transfer previous research about the reward circuit and default mode network underlying alcohol use disorder and depression to achieve a better understanding of neural signatures characterizing their comorbidity. In addition, the neurobiological results will be used to test whether two psychotherapeutic intervention programs, mindfulness-based training and behavioral activation training, are able to positively influence the identified pathomechanisms.
METHODS: By means of functional magnetic resonance imaging (fMRI), 60 comorbid alcohol dependent and depressed patients are compared to 30 patients with depression only, 30 patients with alcohol use disorder only and 30 healthy control participants. Comorbid patients are randomized to either receive a behavioral activation or mindfulness based training and asked to participate in a second fMRI session and 3 month follow-up assessment. Thereby, we plan to explore whether these brief group psychotherapeutic intervention programs are able to positively influence the identified neurobiological pathomechanisms. The primary outcomes are reward and default mode network activity and connectivity evoked by paradigms measuring different facets of reward and emotion processing. Secondary outcome measures include craving and depression scores, as well as relapse rates. Predictors include participants' characteristics, personality traits and indicators of mental health.
DISCUSSION: The objective of the project is to identify common and/or distinct neural signatures underlying the comorbidity of alcohol dependence and depression. If the neurobiological understanding of alcohol addiction and depression is improved, this could potentially serve as a key predictor of treatment response to specific types of behavioral or mindfulness therapies hypothesized to alter reward and resting state systems.
TRIAL REGISTRATION: German Clinical Trial Register DRKS00010249 . The trial was registered January 23th 2017.

PMID: 28454522 [PubMed - in process]

Altered resting-state intra- and inter- network functional connectivity in patients with persistent somatoform pain disorder.

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Altered resting-state intra- and inter- network functional connectivity in patients with persistent somatoform pain disorder.

PLoS One. 2017;12(4):e0176494

Authors: Zhao Z, Huang T, Tang C, Ni K, Pan X, Yan C, Fan X, Xu D, Luo Y

Abstract
Patients with persistent somatoform pain disorder (PSPD) usually experience various functional impairments in pain, emotion, and cognition, which cannot be fully explained by a physiological process or a physical disorder. However, it is still not clear for the mechanism underlying the pathogenesis of PSPD. The present study aimed to explore the intra- and inter-network functional connectivity (FC) differences between PSPD patients and healthy controls (HCs). Functional magnetic resonance imaging (fMRI) was performed in 13 PSPD patients and 23 age- and gender-matched HCs. We used independent component analysis on resting-state fMRI data to calculate intra- and inter-network FCs, and we used the two-sample t-test to detect the FC differences between groups. Spearman correlation analysis was employed to evaluate the correlations between FCs and clinical assessments. As compared to HCs, PSPD patients showed decreased coactivations in the right superior temporal gyrus within the anterior default-mode network and the anterior cingulate cortex within the salience network, and increased coactivations in the bilateral supplementary motor areas within the sensorimotor network and both the left posterior cingulate cortex and the medial prefrontal cortex within the anterior default-mode network. In addition, we found that the PSPD patients showed decreased FNCs between sensorimotor network and audio network as well as visual network, between default-mode network and executive control network as well as audio network and between salience network and executive control network as well as right frontoparietal network, and increased FNCs between sensorimotor network and left frontoparietal network, salience network as well as cerebellum network, which were negatively correlated with the clinical assessments in PSPD patients. Our findings suggest that PSPD patients experience large-scale reorganization at the level of the functional networks, which suggests a possible mechanism underlying the pathogenesis of PSPD.

PMID: 28453543 [PubMed - in process]

Cortical thickness reductions associate with abnormal resting-state functional connectivity in non-neuropsychiatric systemic lupus erythematosus.

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Cortical thickness reductions associate with abnormal resting-state functional connectivity in non-neuropsychiatric systemic lupus erythematosus.

Brain Imaging Behav. 2017 Apr 27;:

Authors: Niu C, Tan X, Liu X, Han K, Niu M, Xu J, Zhao L, Wu Y, Deng F, Huang Q, Wu X, Huang H, Xu Y, Huang R

Abstract
To detect the abnormal cortical thickness and disrupted brain resting-state functional connectivity (RSFC) in patients with systemic lupus erythematosus (SLE) without neuropsychiatric symptoms (non-NPSLE). Using T1-weighted 3D brain structural data, we first determined the regions with abnormal cortical thickness in a cohort of 33 adult female non-NPSLE patients. By taking brain regions with significantly reduced cortical thickness as the seeds, we calculated their RSFC based on the resting-fMRI data and detected the relationship between the RSFC and cortical thickness in the non-NPSLE patients. Compared to the controls, the non-NPSLE patients showed significantly cortical thinning in the left fusiform gyrus (FUS.L), left lingual gyrus (LING.L), right lingual gyrus (LING.R) and left superior frontal cortex (SFC.L). As for the RSFC, statistical analyses indicated that the abnormal cortical thickness in LING.L is associated with increased RSFC in the left posterior cingulate cortex (PCC.L), and cortical thinning in SFC.L associated with decreased RSFC in left cerebellum 6 (CRBL 6.L) in non-NPSLE patients. In addition, in non-NPSLE patients, the decreased cortical thickness in LING.L was correlated to the increased RSFC in PCC.L, and decreased cortical thickness in SFC.L was correlated to the decreased RSFC in CRBL 6.L. Our findings suggest that the cortical abnormalities may affect brain intrinsic connectivity in non-NPSLE patients.

PMID: 28451920 [PubMed - as supplied by publisher]

Effect of DRD4 receptor -616 C/G polymorphism on brain structure and functional connectivity density in pediatric primary nocturnal enuresis patients.

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Effect of DRD4 receptor -616 C/G polymorphism on brain structure and functional connectivity density in pediatric primary nocturnal enuresis patients.

Sci Rep. 2017 Apr 27;7(1):1226

Authors: Yu B, Chang N, Lu Y, Ma H, Liu N, Guo Q

Abstract
The dopamine D4 receptor (DRD4) promoter (-616; rs747302) has been associated with primary nocturnal enuresis (PNE); however, its relationship with neuroimaging has not been investigated. Therefore, we assessed the effects of the DRD4 -616 C/G single nucleotide polymorphism on the gray matter volume (GMV) and functional connectivity density (FCD) during resting-state functional magnetic resonance imaging in children with PNE using voxel-based morphometry and FCD methods. Genomic and imaging data were obtained from 97 children with PNE and 105 healthy controls. DRD4 -616 C/G was genotyped. Arousal from sleep (AS) was assessed on a scale of 1-8. Both the main effect of genotype and the group (PNE/control)-by-genotype interaction on GMV and FCD were calculated. Our results showed that C-allele carriers were associated with a higher AS, decreased GMV and FCD in the pregenual anterior cingulate cortex; children with PNE carrying the C allele exhibit decreased GMV and FCD in the thalamus; however, controls carrying the C allele exhibit increased FCD in the posterior cingulate cortex. These effects of genetic variation of the DRD4 locus may help us understand the genetic susceptibility of the DRD4 -616 C allele to PNE.

PMID: 28450726 [PubMed - in process]

Privileged Functional Connectivity Between the Visual Word Form Area and the Language System.

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Privileged Functional Connectivity Between the Visual Word Form Area and the Language System.

J Neurosci. 2017 Apr 27;:

Authors: Stevens WD, Kravitz DJ, Peng CS, Henry Tessler M, Martin A

Abstract
The visual word form area (VWFA) is a region in the left occipitotemporal sulcus of literate individuals that is purportedly specialized for visual word recognition. However, there is considerable controversy about its functional specificity and connectivity, with some arguing that it serves as a domain-general, rather than word-specific, visual processor. The VWFA is a critical region for testing hypotheses about the nature of cortical organization, because it is known to develop only through experience (i.e., reading acquisition), and widespread literacy is too recent to have influenced genetic determinants of brain organization. Using a combination of advanced fMRI analysis techniques with data from 33 healthy adult human participants, including individual functional localization, multivoxel pattern analysis (MVPA), and high-resolution resting-state functional connectivity (RSFC) analyses, we demonstrate that: 1) the VWFA can discriminate words from non-word letter strings (pseudowords); 2) it has preferential RSFC with Wernicke's area and other core regions of the language system; 3) the strength RSFC between the VWFA and Wernicke's area predicts performance on a semantic classification task with words but not other categories of visual stimuli. Our results are consistent with the hypothesis that the VWFA is specialized for lexical processing of real words by virtue of its functional connectivity with Wernicke's area.SIGNIFICANCE STATEMENTThe visual word form area (VWFA) is critical for determining the nature of category-related organization of the ventral visual system. However, its functional specificity and connectivity are fiercely debated. Recent work concluded that the VWFA is a domain-general, rather than word-specific, visual processor with no preferential functional connectivity with the language system. Using more advanced techniques, our results stand in stark contrast to these earlier findings. We demonstrate that the VWFA is highly specialized for lexical processing of real words, and that a fundamental factor driving this specialization is its preferential intrinsic functional connectivity with core regions of the language system. Our results support the hypothesis that intrinsic functional connectivity contributes to category-related specialization within the human ventral visual system.

PMID: 28450544 [PubMed - as supplied by publisher]

Abnormal Intrinsic Functional Hubs in Severe Male Obstructive Sleep Apnea: Evidence from a Voxel-Wise Degree Centrality Analysis.

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Abnormal Intrinsic Functional Hubs in Severe Male Obstructive Sleep Apnea: Evidence from a Voxel-Wise Degree Centrality Analysis.

PLoS One. 2016;11(10):e0164031

Authors: Li H, Li L, Shao Y, Gong H, Zhang W, Zeng X, Ye C, Nie S, Chen L, Peng D

Abstract
PURPOSE: Obstructive sleep apnea (OSA) has been associated with changes in brain structure and regional function in certain brain areas. However, the functional features of network organization in the whole brain remain largely uncertain. The purpose of this study was to identify the OSA-related spatial centrality distribution of the whole brain functional network and to investigate the potential altered intrinsic functional hubs.
METHODS: Forty male patients with newly confirmed severe OSA on polysomnography, and well-matched good sleepers, participated in this study. All participants underwent a resting-state functional MRI scan and clinical and cognitive evaluation. Voxel-wise degree centrality (DC) was measured across the whole brain, and group difference in DC was compared. The relationship between the abnormal DC value and clinical variables was assessed using a linear correlation analysis.
RESULTS: Remarkably similar spatial distributions of the functional hubs (high DC) were found in both groups. However, OSA patients exhibited a pattern of significantly reduced regional DC in the left middle occipital gyrus, posterior cingulate cortex, left superior frontal gyrus, and bilateral inferior parietal lobule, and DC was increased in the right orbital frontal cortex, bilateral cerebellum posterior lobes, and bilateral lentiform nucleus, including the putamen, extending to the hippocampus, and the inferior temporal gyrus, which overlapped with the functional hubs. Furthermore, a linear correlation analysis revealed that the DC value in the posterior cingulate cortex and left superior frontal gyrus were positively correlated with Montreal cognitive assessment scores, The DC value in the left middle occipital gyrus and bilateral inferior parietal lobule were negatively correlated with apnea-hypopnea index and arousal index in OSA patients.
CONCLUSION: Our findings suggest that OSA patients exhibited specific abnormal intrinsic functional hubs including relatively reduced and increased DC. This expands our understanding of the functional characteristics of OSA, which may provide new insights into understanding the dysfunction and pathophysiology of OSA patients.

PMID: 27723821 [PubMed - indexed for MEDLINE]

The Right Dorsal Premotor Mosaic: Organization, Functions, and Connectivity.

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The Right Dorsal Premotor Mosaic: Organization, Functions, and Connectivity.

Cereb Cortex. 2017 Mar 01;27(3):2095-2110

Authors: Genon S, Li H, Fan L, Müller VI, Cieslik EC, Hoffstaedter F, Reid AT, Langner R, Grefkes C, Fox PT, Moebus S, Caspers S, Amunts K, Jiang T, Eickhoff SB

Abstract
The right dorsal premotor cortex (PMd) of humans has been reported to be involved in a broad range of motor and cognitive functions. We explored the basis of this behavioral heterogeneity by performing a connectivity-based parcellation using meta-analytic approach applied to PMd coactivations. We compared our connectivity-based parcellation results with parcellations obtained through resting-state functional connectivity and probabilistic diffusion tractography. Functional connectivity profiles and behavioral decoding of the resulting PMd subregions allowed characterizing their respective behavior profile. These procedures divided the right PMd into 5 distinct subregions that formed a cognitive-motor gradient along a rostro-caudal axis. In particular, we found 1) a rostral subregion functionally connected with prefrontal cortex, which likely supports high-level cognitive processes, such as working memory, 2) a central subregion showing a mixed behavioral profile and functional connectivity to parietal regions of the dorsal attention network, and 3) a caudal subregion closely integrated with the motor system. Additionally, we found 4) a dorsal subregion, preferentially related to hand movements and connected to both cognitive and motor regions, and 5) a ventral subregion, whose functional profile fits the concept of an eye movement-related field. In conclusion, right PMd may be considered as a functional mosaic formed by 5 subregions.

PMID: 26965906 [PubMed - indexed for MEDLINE]

Early Development of Functional Network Segregation Revealed by Connectomic Analysis of the Preterm Human Brain.

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Early Development of Functional Network Segregation Revealed by Connectomic Analysis of the Preterm Human Brain.

Cereb Cortex. 2017 Mar 01;27(3):1949-1963

Authors: Cao M, He Y, Dai Z, Liao X, Jeon T, Ouyang M, Chalak L, Bi Y, Rollins N, Dong Q, Huang H

Abstract
Human brain functional networks are topologically organized with nontrivial connectivity characteristics such as small-worldness and densely linked hubs to support highly segregated and integrated information processing. However, how they emerge and change at very early developmental phases remains poorly understood. Here, we used resting-state functional MRI and voxel-based graph theory analysis to systematically investigate the topological organization of whole-brain networks in 40 infants aged around 31 to 42 postmenstrual weeks. The functional connectivity strength and heterogeneity increased significantly in primary motor, somatosensory, visual, and auditory regions, but much less in high-order default-mode and executive-control regions. The hub and rich-club structures in primary regions were already present at around 31 postmenstrual weeks and exhibited remarkable expansions with age, accompanied by increased local clustering and shortest path length, indicating a transition from a relatively random to a more organized configuration. Moreover, multivariate pattern analysis using support vector regression revealed that individual brain maturity of preterm babies could be predicted by the network connectivity patterns. Collectively, we highlighted a gradually enhanced functional network segregation manner in the third trimester, which is primarily driven by the rapid increases of functional connectivity of the primary regions, providing crucial insights into the topological development patterns prior to birth.

PMID: 26941380 [PubMed - indexed for MEDLINE]

Magnetic resonance imaging connectivity for the prediction of seizure outcome in temporal lobe epilepsy.

Fri, 04/28/2017 - 10:20

Magnetic resonance imaging connectivity for the prediction of seizure outcome in temporal lobe epilepsy.

Epilepsia. 2017 Apr 27;:

Authors: Morgan VL, Englot DJ, Rogers BP, Landman BA, Cakir A, Abou-Khalil BW, Anderson AW

Abstract
OBJECTIVE: Currently, approximately 60-70% of patients with unilateral temporal lobe epilepsy (TLE) remain seizure-free 3 years after surgery. The goal of this work was to develop a presurgical connectivity-based biomarker to identify those patients who will have an unfavorable seizure outcome 1-year postsurgery.
METHODS: Resting-state functional and diffusion-weighted 3T magnetic resonance imaging (MRI) was acquired from 22 unilateral (15 right, 7 left) patients with TLE and 35 healthy controls. A seizure propagation network was identified including ipsilateral (to seizure focus) and contralateral hippocampus, thalamus, and insula, with bilateral midcingulate and precuneus. Between each pair of regions, functional connectivity based on correlations of low frequency functional MRI signals, and structural connectivity based on streamline density of diffusion MRI data were computed and transformed to metrics related to healthy controls of the same age.
RESULTS: A consistent connectivity pattern representing the network expected in patients with seizure-free outcome was identified using eight patients who were seizure-free at 1-year postsurgery. The hypothesis that increased similarity to the model would be associated with better seizure outcome was tested in 14 other patients (Engel class IA, seizure-free: n = 5; Engel class IB-II, favorable: n = 4; Engel class III-IV, unfavorable: n = 5) using two similarity metrics: Pearson correlation and Euclidean distance. The seizure-free connectivity model successfully separated all the patients with unfavorable outcome from the seizure-free and favorable outcome patients (p = 0.0005, two-tailed Fisher's exact test) through the combination of the two similarity metrics with 100% accuracy. No other clinical and demographic predictors were successful in this regard.
SIGNIFICANCE: This work introduces a methodologic framework to assess individual patients, and demonstrates the ability to use network connectivity as a potential clinical tool for epilepsy surgery outcome prediction after more comprehensive validation.

PMID: 28448683 [PubMed - as supplied by publisher]

Spontaneous migraine attack causes alterations in default mode network connectivity: a resting-state fMRI case report.

Fri, 04/28/2017 - 10:20
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Spontaneous migraine attack causes alterations in default mode network connectivity: a resting-state fMRI case report.

BMC Res Notes. 2017 Apr 26;10(1):165

Authors: Edes AE, Kozak LR, Magyar M, Zsombok T, Kokonyei G, Bagdy G, Juhasz G

Abstract
BACKGROUND: Although migraine is one of the most investigated neurologic disorders, we do not have a perfect neuroimaging biomarker for its pathophysiology. One option to improve our knowledge is to study resting-state functional connectivity in and out of headache pain. However, our understanding of the functional connectivity changes during spontaneous migraine attack is partial and incomplete.
CASE PRESENTATION: Using resting-state functional magnetic resonance imaging we assessed a 24-year old woman affected by migraine without aura at two different times: during a spontaneous migraine attack and in interictal phase. Seed-to-voxel whole brain analysis was carried out using the posterior cingulate cortex as a seed, representing the default mode network (DMN). Our results showed decreased intrinsic connectivity within core regions of the DMN with an exception of a subsystem including the dorsal medial and superior frontal gyri, and the mid-temporal gyrus which is responsible for pain interpretation and control. In addition, increased connectivity between the DMN and pain and specific migraine-related areas, such as the pons and hypothalamus, developed during the spontaneous migraine attack.
CONCLUSION: Our preliminary results provide further support for the hypothesis that alterations of the DMN functional connectivity during migraine headache may lead to maladaptive top-down modulation of migraine pain-related areas which might be a specific biomarker for migraine.

PMID: 28446211 [PubMed - in process]

Right brain, left brain in depressive disorders: Clinical and theoretical implications of behavioral, electrophysiological and neuroimaging findings.

Thu, 04/27/2017 - 15:40

Right brain, left brain in depressive disorders: Clinical and theoretical implications of behavioral, electrophysiological and neuroimaging findings.

Neurosci Biobehav Rev. 2017 Apr 23;:

Authors: Bruder GE, Stewart JW, McGrath PJ

Abstract
The right and left side of the brain are asymmetric in anatomy and function. We review electrophysiological (EEG and event-related potential), behavioral (dichotic and visual perceptual asymmetry), and neuroimaging (PET, MRI, NIRS) evidence of right-left asymmetry in depressive disorders. Recent electrophysiological and fMRI studies of emotional processing have provided new evidence of altered laterality in depressive disorders. EEG alpha asymmetry and neuroimaging findings at rest and during cognitive or emotional tasks are consistent with reduced left prefrontal activity in depressed patients, which may impair downregulation of amygdala response to negative emotional information. Dichotic listening and visual hemifield findings for non-verbal or emotional processing have revealed abnormal perceptual asymmetry in depressive disorders, and electrophysiological findings have shown reduced right-lateralized responsivity to emotional stimuli in occipitotemporal or parietotemporal cortex. We discuss models of neural networks underlying these alterations. Of clinical relevance, individual differences among depressed patients on measures of right-left brain function are related to diagnostic subtype of depression, comorbidity with anxiety disorders, and clinical response to antidepressants or cognitive behavioral therapy.

PMID: 28445740 [PubMed - as supplied by publisher]

Resting-state functional connectivity of the amygdala in suicide attempters with major depressive disorder.

Thu, 04/27/2017 - 15:40

Resting-state functional connectivity of the amygdala in suicide attempters with major depressive disorder.

Prog Neuropsychopharmacol Biol Psychiatry. 2017 Apr 23;:

Authors: Kang SG, Na KS, Choi JW, Kim JH, Son YD, Lee YJ

Abstract
In this study, we investigated the difference in resting-state functional connectivity (RSFC) of the amygdala between suicide attempters and non-suicide attempters with major depressive disorder (MDD) using functional magnetic resonance imaging (fMRI). This study included 19 suicide attempters with MDD and 19 non-suicide attempters with MDD. RSFC was compared between the two groups and the regression analyses were conducted to identify the correlation between RSFC and Scale for Suicide Ideation (SSI) scores in the suicide attempt group. Statistical significance was set at p-value (uncorrected) <0.005 with k≥28 voxels. Compared with non-suicide attempters, suicide attempters showed significantly increased RSFC of the left amygdala with the right insula and left superior orbitofrontal area, and increased RSFC of the right amygdala with the left middle temporal area. The regression analysis showed a significant correlation between the SSI total score and RSFC of the right amygdala with the right parahippocampal area in the suicide attempt group. The present RSFC findings provide evidence of a functional neural basis and will help reveal the pathophysiology underlying suicidality in subjects with MDD.

PMID: 28445688 [PubMed - as supplied by publisher]

Brain Resting State Functional Connectivity is preserved under Sevoflurane Anesthesia in patients with Pervasive Developmental disorders - a pilot study.

Thu, 04/27/2017 - 15:40

Brain Resting State Functional Connectivity is preserved under Sevoflurane Anesthesia in patients with Pervasive Developmental disorders - a pilot study.

Brain Connect. 2017 Apr 26;:

Authors: Venkat Raghavan L, Bharadwaj S, Wourms V, Tan A, Jurkiewicz MT, Mikulis DJ, Crawley AP

Abstract
Background Functional connectivity studies play a huge role in understanding the relationship between the network connections and the behavioral phenotype of patients with Pervasive developmental disorders (PDD). However, some patients with PDD may not tolerate the imaging procedure while awake and they often need general anesthesia. General anesthesia is a confounding factor in functional imaging studies due to its effect on the functional connectivity. The objective of this study is to look at the resting state functional connectivity (RS-FC) under sevoflurane anesthesia in patients with pervasive developmental disorders. Method Adults with PDD scheduled for MRI of the brain under general anesthesia were recruited for the study. Resting state fMRI scans were acquired in all patients on a 3-Tesla scanner at 1 Minimum Alveolar Concentration (MAC) of sevoflurane. During the study period, end-tidal carbon dioxide and blood pressure were maintained at baseline value. Spontaneous BOLD fluctuations were measured, and a seed-voxel analysis done to identify the resting state networks. Subjects' data were compared with data from sixteen non-anesthetised healthy controls.. Results A total of 13 patients was studied. Six networks were investigated, the default mode network (DMN), executive control network (ECN), salience network (SN) as well as the auditory, visual and sensorimotor networks. At 1 MAC sevoflurane anesthesia, RS-FC was preserved in all the networks. Secondary analysis of connectivity showed a decrease in connectivity within the thalamus and an increase in DMN-ECN and DMN-SN cross-network connectivity in the anesthetized patient group compared to healthy controls. Conclusion Previous reports suggested that even mild levels of anesthesia could reduce overall fluctuation levels in major brain networks such as the DMN and ECN. However, our results provide strong evidence that these networks can sustain detectable levels of activity in patients with pervasive developmental disorders even under deep levels of anesthesia.

PMID: 28443736 [PubMed - as supplied by publisher]

Enhanced Functional Connectivity between the Bilateral Primary Motor Cortices after Acupuncture at Yanglingquan (GB34) in Right-Hemispheric Subcortical Stroke Patients: A Resting-State fMRI Study.

Thu, 04/27/2017 - 15:40
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Enhanced Functional Connectivity between the Bilateral Primary Motor Cortices after Acupuncture at Yanglingquan (GB34) in Right-Hemispheric Subcortical Stroke Patients: A Resting-State fMRI Study.

Front Hum Neurosci. 2017;11:178

Authors: Ning Y, Li K, Fu C, Ren Y, Zhang Y, Liu H, Cui F, Zou Y

Abstract
Increasing neuroimaging researches in stroke rehabilitation had revealed the neural mechanisms of rehabilitation therapy. However, little was known about the neural mechanisms of acupuncture therapy in subcortical stroke patients. The aim of this study was to investigate the changes of functional connectivity (FC) between the bilateral primary motor cortices (M1s) after acupuncture intervention in right subcortical stroke patients. Twenty right-hemispheric subcortical stroke patients and 20 healthy subjects were recruited to undergo one functional magnetic resonance imaging (fMRI) scanning. The scanning consisted of resting-state fMRI before and after needling at Yanglinquan (GB34), and task-evoked fMRI. The most significant active point during the left passive thumb-to-index task was chosen as the seed point. The seed-based FC analysis of the bilateral M1s was performed. Stroke patients revealed decreased FC between the bilateral M1s compared with healthy subjects, and the decreased FC was significantly enhanced after acupuncture at GB34. Acupuncture could increase the intrinsically decreased FC between the bilateral M1s which provided further insight into the neural mechanisms of acupuncture for motor function recovery in stroke patients.

PMID: 28443010 [PubMed - in process]

The effect of regulatory mode on procrastination: Bi-stable parahippocampus connectivity with dorsal anterior cingulate and anterior prefrontal cortex.

Thu, 04/27/2017 - 15:40
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The effect of regulatory mode on procrastination: Bi-stable parahippocampus connectivity with dorsal anterior cingulate and anterior prefrontal cortex.

Behav Brain Res. 2017 Apr 22;:

Authors: Zhang C, Ni Y, Feng T

Abstract
Previous research has elucidated that procrastination can be influenced by regulatory mode orientations. However, the neural mechanism of regulatory modes affecting procrastination is not well understood. To address this question, we employed resting-state functional magnetic resonance imaging (RS-fMRI) to test the influence of two regulatory modes (assessment and locomotion) on procrastination. The behavioral results showed that procrastination was positively correlated with assessment orientation but negatively correlated with locomotion orientation. Neuroimaging results indicated that the functional connectivity between parahippocampal cortex (PHC) and dorsal anterior cingulate (dACC) was negatively correlated with assessment scores, while the functional connectivity between anterior prefrontal cortex (aPFC) and parahippocampal cortex (PHC) was negatively correlated with locomotion scores. Critically, mediation analysis showed that the different effects of two distinct regulatory modes on procrastination were mediated by PHC-dACC and aPFC-PHC functional connectivity respectively. These results suggested that people's procrastination could be predicted by regulatory mode orientations, which is mediated by PHC connectivity with dACC and aPFC respectively. The present study extends our knowledge on procrastination and provides neural mechanism for understanding the link between regulatory mode orientations and procrastination.

PMID: 28442352 [PubMed - as supplied by publisher]

Impact of aberrant cerebral perfusion on resting-state functional MRI: A preliminary investigation of Moyamoya disease.

Wed, 04/26/2017 - 14:40
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Impact of aberrant cerebral perfusion on resting-state functional MRI: A preliminary investigation of Moyamoya disease.

PLoS One. 2017;12(4):e0176461

Authors: Wang Y, Wang L, Qiao P, Sheng F, Han C, Ye E, Lei Y, Yan F, Chen S, Zhu Y, Mi G, Li G, Yang Z

Abstract
The impact of chronic cerebral hypoperfusion on resting-state blood oxygen level-dependent signal fluctuations remains unknown. We aimed to determine whether chronic ischemia induces changes in amplitude of low-frequency fluctuations (ALFF) and to investigate the correlation between ALFF and perfusion-weighted magnetic resonance imaging (PWI) parameters in patients with moyamoya disease (MMD). Thirty patients with pre- and postoperative resting-state functional magnetic resonance imaging and PWI were included, and thirty normal controls underwent resting-state functional magnetic resonance imaging. A decrease in preoperative frontal lobe ALFF was observed in patients with MMD. Postoperative frontal lobe ALFF showed moderate improvement but still remained lower than those in normal controls. The values of mean transit time and time-to-peak, but not cerebral blood volume and cerebral blood flow, correlated significantly with frontal lobe ALFF. Moreover, there were significant negative correlations between changes in frontal lobe PWI parameters and changes in frontal lobe ALFF on both operated side and contralateral side after the unilateral revascularization surgery. Our results demonstrate that reduced ALFF are closely related to the abnormal PWI parameters and vary with the alteration of cerebral perfusion in patients with MMD.

PMID: 28441445 [PubMed - in process]

Instability of default mode network connectivity in major depression: a two-sample confirmation study.

Wed, 04/26/2017 - 14:40
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Instability of default mode network connectivity in major depression: a two-sample confirmation study.

Transl Psychiatry. 2017 Apr 25;7(4):e1105

Authors: Wise T, Marwood L, Perkins AM, Herane-Vives A, Joules R, Lythgoe DJ, Luh WM, Williams SCR, Young AH, Cleare AJ, Arnone D

Abstract
Major depression is associated with altered static functional connectivity in various brain networks, particularly the default mode network (DMN). Dynamic functional connectivity is a novel tool with little application in affective disorders to date, and holds the potential to unravel fluctuations in connectivity strength over time in major depression. We assessed stability of connectivity in major depression between the medial prefrontal cortex (mPFC) and posterior cingulate cortex (PCC), key nodes in the DMN that are implicated in ruminative cognitions. Functional connectivity stability between the mPFC and PCC over the course of a resting-state functional magnetic resonance imaging (fMRI) scan was compared between medication-free patients with major depression and healthy controls matched for age, sex and handedness. We tested replicability of the results in an independent sample using multi-echo resting-state fMRI. The primary sample included 20 patients and 19 controls, while the validation sample included 19 patients and 19 controls. Greater connectivity variability was detected in major depression between mPFC and PCC. This was demonstrated in both samples indicating that the results were reliable and were not influenced by the fMRI acquisition approach used. Our results demonstrate that alterations within the DMN in major depression go beyond changes in connectivity strength and extend to reduced connectivity stability within key DMN regions. Findings were robustly replicated across two independent samples. Further research is necessary to better understand the nature of these fluctuations in connectivity and their relationship to the aetiology of major depression.

PMID: 28440813 [PubMed - in process]

Altered intra- and interregional synchronization in the absence of the corpus callosum: a resting-state fMRI study.

Wed, 04/26/2017 - 14:40
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Altered intra- and interregional synchronization in the absence of the corpus callosum: a resting-state fMRI study.

Neurol Sci. 2017 Apr 24;:

Authors: Zuo L, Wang S, Yuan J, Gu H, Zhou Y, Jiang T

Abstract
Agenesis of the corpus callosum (AgCC) can result in subtle to severe cognitive deficits. Individuals with impaired cognition often show abnormalities on resting-state functional magnetic resonance imaging (rs-fMRI). This study used rs-fMRI to investigate changes in regional homogeneity (ReHo) and functional connectivity (FC) among individuals with AgCC. AgCC individuals (n = 10) and age-, sex-, and education-matched healthy control subjects (n = 19) were included in this study. The ReHo values were calculated to represent spontaneous brain activity. The regions which showed altered ReHo were selected as seeds to compare FC with the whole brain between the AgCC group and the healthy control group. Compared with healthy control subjects, the AgCC individuals had increased ReHo in the left anterior cingulate gyrus, left rolandic operculum, and right precuneus and decreased ReHo in the right calcarine, right cingual gyrus and right cuneus gyrus. The right calcarine and the right lingual gyrus in the AgCC exhibited decreased FC with bilateral cuneus, superior occipital gyrus, Rolandic operculum, superior temporal gyrus, posterior central gyrus, and midcingulate gyrus.The right cuneus gyrus in the AgCC individuals exhibited decreased FC with the bilateral calcarine gyrus, left cuneus, and left superior occipital gyrus. Our study revealed several subareas within the visual cortex exhibited remarkable abnormalities of spontaneous brain activity and decreased FC with the higher-order cognitive cortex.The abnormalities of ReHo and FC in AgCC individuals may provide new insights into the neurological pathophysiology.

PMID: 28439672 [PubMed - as supplied by publisher]

Richness in Functional Connectivity Depends on the Neuronal Integrity within the Posterior Cingulate Cortex.

Wed, 04/26/2017 - 14:40
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Richness in Functional Connectivity Depends on the Neuronal Integrity within the Posterior Cingulate Cortex.

Front Neurosci. 2017;11:184

Authors: Lord AR, Li M, Demenescu LR, van den Meer J, Borchardt V, Krause AL, Heinze HJ, Breakspear M, Walter M

Abstract
The brain's connectivity skeleton-a rich club of strongly interconnected members-was initially shown to exist in human structural networks, but recent evidence suggests a functional counterpart. This rich club typically includes key regions (or hubs) from multiple canonical networks, reducing the cost of inter-network communication. The posterior cingulate cortex (PCC), a hub node embedded within the default mode network, is known to facilitate communication between brain networks and is a key member of the "rich club." Here, we assessed how metabolic signatures of neuronal integrity and cortical thickness influence the global extent of a functional rich club as measured using the functional rich club coefficient (fRCC). Rich club estimation was performed on functional connectivity of resting state brain signals acquired at 3T in 48 healthy adult subjects. Magnetic resonance spectroscopy was measured in the same session using a point resolved spectroscopy sequence. We confirmed convergence of functional rich club with a previously established structural rich club. N-acetyl aspartate (NAA) in the PCC is significantly correlated with age (p = 0.001), while the rich club coefficient showed no effect of age (p = 0.106). In addition, we found a significant quadratic relationship between fRCC and NAA concentration in PCC (p = 0.009). Furthermore, cortical thinning in the PCC was correlated with a reduced rich club coefficient after accounting for age and NAA. In conclusion, we found that the fRCC is related to a marker of neuronal integrity in a key region of the cingulate cortex. Furthermore, cortical thinning in the same area was observed, suggesting that both cortical thinning and neuronal integrity in the hub regions influence functional integration of at a whole brain level.

PMID: 28439224 [PubMed - in process]

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