New resting-state fMRI related studies at PubMed

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resting state fMRI; +21 new citations

Fri, 12/07/2018 - 16:46

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resting state fMRI

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Tracking the dynamic functional connectivity structure of the human brain across the adult lifespan.

Thu, 12/06/2018 - 16:00

Tracking the dynamic functional connectivity structure of the human brain across the adult lifespan.

Hum Brain Mapp. 2018 Dec 04;:

Authors: Xia Y, Chen Q, Shi L, Li M, Gong W, Chen H, Qiu J

Abstract
The transition from early adulthood to the elder is marked by functional and structural brain transformations. Many previous studies examined the correlation between the functional connectivity (FC) and aging using resting-state fMRI. Results showed that the changes in FC are linked to aging as well as the cognitive ability changes. However, some researchers proposed that the FC is not static but dynamic changes during the resting-state fMRI scan. In this study, we examined the correlation between the resting-state dynamic functional network connectivity and age using resting scan data of 434 subjects. The results suggested: (a) age is negatively associated with variability of dynamic functional network connectivity state; (b) the dwell time of each age range spends in each state is different; (c) the dynamic graph metrics curve of each age ranges is different and 19-30 age range has the largest average global efficiency and average local efficiency; (d) some dynamic functional network connectivity measures were correlated to the certain cognitive ability. Overall, the results suggested the changes in dynamic functional network connectivity measures may be a characteristic of the aging process and in further investigations may provide a deep understanding of the aging process.

PMID: 30515914 [PubMed - as supplied by publisher]

Aberrant Resting-State Functional Connectivity in the Default Mode Network in Pediatric Bipolar Disorder Patients with and without Psychotic Symptoms.

Thu, 12/06/2018 - 16:00

Aberrant Resting-State Functional Connectivity in the Default Mode Network in Pediatric Bipolar Disorder Patients with and without Psychotic Symptoms.

Neurosci Bull. 2018 Dec 04;:

Authors: Zhong Y, Wang C, Gao W, Xiao Q, Lu D, Jiao Q, Su L, Lu G

Abstract
Mood disorders/psychosis have been associated with dysfunctions in the default mode network (DMN). However, the relative contributions of DMN regions to state and trait disturbances in pediatric bipolar disorder (PBD) remain unclear. The aim of this study was to investigate the possible mechanisms of PBD through brain imaging and explore the influence of psychotic symptoms on functional alterations in PBD patients. Twenty-nine psychotic and 26 non-psychotic PBD patients, as well as 19 age- and sex-matched healthy controls underwent a resting-state functional MRI scan and the data were analyzed by independent component analysis. The DMN component from the fMRI data was extracted for each participant. Spearman's rank correlation analysis was performed between aberrant connectivity and clinical measurements. The results demonstrated that psychotic PBD was characterized by aberrant DMN connectivity in the anterior cingulate cortex/medial prefrontal cortex, bilateral caudate nucleus, bilateral angular gyri, and left middle temporal gyrus, while non-psychotic PBD was not, suggesting further impairment with the development of psychosis. In summary, we demonstrated unique impairment in DMN functional connectivity in the psychotic PBD group. These specific neuroanatomical abnormalities may shed light on the underlying pathophysiology and presentation of PBD.

PMID: 30515682 [PubMed - as supplied by publisher]

The devil is in the detail: exploring the intrinsic neural mechanisms that link attention-deficit/hyperactivity disorder symptomatology to ongoing cognition.

Thu, 12/06/2018 - 16:00

The devil is in the detail: exploring the intrinsic neural mechanisms that link attention-deficit/hyperactivity disorder symptomatology to ongoing cognition.

Psychol Med. 2018 Dec 05;:1-10

Authors: Vatansever D, Bozhilova NS, Asherson P, Smallwood J

Abstract
BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) is a developmental condition that profoundly affects quality of life. Although mounting evidence now suggests uncontrolled mind-wandering as a core aspect of the attentional problems associated with ADHD, the neural mechanisms underpinning this deficit remains unclear. To that extent, competing views argue for (i) excessive generation of task-unrelated mental content, or (ii) deficiency in the control of task-relevant cognition.
METHODS: In a cross-sectional investigation of a large neurotypical cohort (n = 184), we examined alterations in the intrinsic brain functional connectivity architecture of the default mode (DMN) and frontoparietal (FPN) networks during resting state functional magnetic resonance imaging in relation to ADHD symptomatology, which could potentially underlie changes in ongoing thought within variable environmental contexts.
RESULTS: The results illustrated that ADHD symptoms were linked to lower levels of detail in ongoing thought while the participants made more difficult, memory based decisions. Moreover, greater ADHD scores were associated with lower levels of connectivity between the DMN and right sensorimotor cortex, and between the FPN and right ventral visual cortex. Finally, a combination of high levels of ADHD symptomology with reduced FPN connectivity to the visual cortex was associated with reduced levels of detail in thought.
CONCLUSIONS: The results of our study suggest that the frequent mind-wandering observed in ADHD may be an indirect consequence of the deficient control of ongoing cognition in response to increasing environmental demands, and that this may partly arise from dysfunctions in the intrinsic organisation of the FPN at rest.

PMID: 30514410 [PubMed - as supplied by publisher]

Reconfigured functional network dynamics in adult moyamoya disease: a resting-state fMRI study.

Wed, 12/05/2018 - 21:00

Reconfigured functional network dynamics in adult moyamoya disease: a resting-state fMRI study.

Brain Imaging Behav. 2018 Dec 03;:

Authors: Lei Y, Song B, Chen L, Su J, Zhang X, Ni W, Yu Y, Xu B, Yu L, Gu Y, Mao Y

Abstract
Treatment of vascular cognitive impairment (VCI) in adult moyamoya disease (MMD) is still unclear because of its unveiled neural synchronization. This study introduced a dynamic measurement of connectivity number entropy (CNE) to characterize both spatial and temporal dimensions of network interactions. Fifty-one patients with MMD were recruited (27 with VCI and 24 with intact cognition), as well as 26 normal controls (NCs). Static network properties were first examined to confirm its aberrance in MMD with VCI. Then, the dynamic measurement of CNE was used to detect the deteriorated flexibility of MMD with VCI at global, regional, and network levels. Finally, dynamic reconfiguration of flexible and specialized regions was traced across the three groups. Graph theory analysis indicated that MMD exhibited "small-world" network topology but presented with a deviating pattern from NC as the disease progressed in all topologic metrics of integration, segregation, and small-worldness. Subsequent dynamic analysis showed significant CNE differences among the three groups at both global (p < 0.001) and network levels (default mode network, p = 0.004; executive control network, p = 0.001). Specifically, brain regions related to key aspects of information processing exhibited significant CNE changes across the three groups. Furthermore, CNE values of both flexible and specialized regions changed with impaired cognition. This study not only sheds light on both the static and dynamic organizational principles behind network changes in adult MMD for the first time, but also provides a new methodologic viewpoint to acquire more knowledge of its pathophysiology and treatment direction.

PMID: 30511114 [PubMed - as supplied by publisher]

Abnormal functional connectivity and degree centrality in anterior cingulate cortex in patients with long-term sensorineural hearing loss.

Wed, 12/05/2018 - 21:00

Abnormal functional connectivity and degree centrality in anterior cingulate cortex in patients with long-term sensorineural hearing loss.

Brain Imaging Behav. 2018 Dec 03;:

Authors: Luan Y, Wang C, Jiao Y, Tang T, Zhang J, Lu C, Salvi R, Teng GJ

Abstract
Wide-ranging functional remodeling is involved in sensorineural hearing loss (SNHL), which has been demonstrated to have accumulated risk of cognitive and emotional dysfunction. Anterior cingulate cortex (ACC) has close connections with the auditory area and plays a vital role in regulating the cognitive, emotional and auditory processing. However, the functional reorganization of the ACC and its associations with potential cognitive and emotional impairments involved in SNHL have never been explored. Thirty-five patients with long-term bilateral SNHL and thirty-five well-matched healthy controls were recruited for this study. We analyzed resting-state functional MRI data and neuropsychological test scores from these participants. Functional connectivity of the ACC subdivisions, voxel-wise degree centrality (DC) and intra-/internetwork connectivity were computed to evaluate the functional changes related to cognitive, emotional and multiple sensory functions. ANCOVA and post hoc analyses were conducted to identify differences between normal controls and patients for each measure. Widespread alterations of functional coupling with the subdivisions of the ACC were observed in regions involved in cognitive, emotional and multiple sensory processing, particularly within the cingulo-opercular network (CON), default mode network (DMN) and auditory network (AN) in the SNHL patients. Outstandingly increased DC was found in the ACC. Network analyses showed significant intra- and inter-network hypo-synchronization in the SNHL patients. Importantly, the functional alterations were associated with the anxiety states and the processing speed. The functional reorganization in the ACC and the disturbance of intrinsic multiple network functional connectivity among the CON, DMN, and AN were found in the SNHL patient, which might shed more lights on potential substrates underlying the cognitive and emotional impairments related to the SNHL.

PMID: 30511112 [PubMed - as supplied by publisher]

Nicotine in action: cigarette smoking modulated homotopic functional connectivity in schizophrenia.

Wed, 12/05/2018 - 21:00

Nicotine in action: cigarette smoking modulated homotopic functional connectivity in schizophrenia.

Brain Imaging Behav. 2018 Dec 03;:

Authors: Liao W, Yang S, Li J, Fan YS, Duan X, Cui Q, Chen H

Abstract
Cigarette smoking is intimately associated with both early onset and increased severity of schizophrenia. The self-medication hypothesis suggests that nicotine can relieve or restore neurocognitive deficits and symptoms associated with schizophrenia. Schizophrenia patients and healthy subjects who smoked showed deficits in communication between their hemispheres. These homotopic connectivity mechanisms associated with both schizophrenia and smoking comorbidity were largely unknown until now. A mixed sample including patients with schizophrenia (22 smokers and 27 non-smokers) and healthy controls (22 smokers and 21 non-smokers) based on clinical diagnoses and cigarette dependence were recruited for the current study. All subjects underwent resting-state functional magnetic resonance imaging to determine possible interactions between schizophrenia and smoking, and to determine the main effects of schizophrenia and smoking on homotopic functional connectivity. Decreased homotopic functional connectivity of the subgenual anterior cingulate cortex suggested a main effect of schizophrenia and smoking-an additive effect. Furthermore, we found an antagonistic interaction effect between schizophrenia and smoking located in the ventrolateral prefrontal cortex (VLPFC). In addition, the connectivity strength of the bilateral VLPFC was negatively correlated with the Positive and Negative Syndrome Scale Negative scores and positively correlated with lifetime smoking. These results suggest that smoking has multiple effects on the modulation of interhemispheric connectivity in schizophrenia. Our findings provide valuable information underlying the pathophysiological mechanisms of schizophrenia and offer a potential target for future clinical treatment of schizophrenia and smoking comorbidity.

PMID: 30511111 [PubMed - as supplied by publisher]

Dimensional Complexity of the Resting Brain in Healthy Aging, Using a Normalized MPSE.

Wed, 12/05/2018 - 21:00

Dimensional Complexity of the Resting Brain in Healthy Aging, Using a Normalized MPSE.

Front Hum Neurosci. 2018;12:451

Authors: Scheel N, Franke E, Münte TF, Madany Mamlouk A

Abstract
Spontaneous fluctuations of resting-state functional connectivity have been studied in many ways, but grasping the complexity of brain activity has been difficult. Dimensional complexity measures, which are based on Eigenvalue (EV) spectrum analyses (e.g., Ω entropy) have been successfully applied to EEG data, but have not been fully evaluated on functional MRI recordings, because only through the recent introduction of fast multiband fMRI sequences, feasable temporal resolutions are reached. Combining the Eigenspectrum normalization of Ω entropy and the scalable architecture of the so called Multivariate Principal Subspace Entropy (MPSE) leads to a new complexity measure, namely normalized MPSE (nMPSE). It allows functional brain complexity analyses at varying levels of EV energy, independent from global shifts in data variance. Especially the restriction of the EV spectrum to the first dimensions, carrying the most prominent data variance, can act as a filter to reveal the most discriminant factors of dependent variables. Here we look at the effects of healthy aging on the dimensional complexity of brain activity. We employ a large open access dataset, providing a great number of high quality fast multiband recordings. Using nMPSE on whole brain, regional, network and searchlight approaches, we were able to find many age related changes, i.e., in sensorimotoric and right inferior frontal brain regions. Our results implicate that research on dimensional complexity of functional MRI recordings promises to be a unique resource for understanding brain function and for the extraction of biomarkers.

PMID: 30510506 [PubMed]

Replication of Resting State-Task Network Correspondence and Novel Findings on Brain Network Activation During Task fMRI in the Human Connectome Project Study.

Wed, 12/05/2018 - 21:00

Replication of Resting State-Task Network Correspondence and Novel Findings on Brain Network Activation During Task fMRI in the Human Connectome Project Study.

Sci Rep. 2018 Dec 03;8(1):17543

Authors: Nickerson LD

Abstract
There have been many recent reports highlighting a crisis in replication and reliability of research in psychology, neuroscience, and neuroimaging. After a series of reports uncovered various methodological problems with functional magnetic resonance imaging (fMRI) research, considerable attention has been given to principles and practices to improve reproducibility of neuroimaging findings, including promotion of openness, transparency, and data sharing. However, much less attention has been given to use of open access neuroimaging datasets to conduct replication studies. A major barrier to reproducing neuroimaging studies is their high cost, in money and labor, and utilizing such datasets is an obvious solution for breaking down this barrier. The Human Connectome Project (HCP) is an open access dataset consisting of extensive neurological, behavioral, and genetics assessments and neuroimaging data from over 1,100 individuals. In the present study, findings supporting the replication of a highly cited neuroimaging study that showed correspondence between resting state and task brain networks, and novel findings on activation of brain networks during task performance that arose with this exercise are presented as a demonstration of use of the HCP for replication studies.

PMID: 30510165 [PubMed - in process]

Cerebellar structural and functional abnormalities in first-episode and drug-naive patients with schizophrenia: A meta-analysis.

Tue, 12/04/2018 - 13:20
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Cerebellar structural and functional abnormalities in first-episode and drug-naive patients with schizophrenia: A meta-analysis.

Psychiatry Res Neuroimaging. 2018 Nov 22;283:24-33

Authors: Ding Y, Ou Y, Pan P, Shan X, Chen J, Liu F, Zhao J, Guo W

Abstract
Schizophrenia (SZ) is a mental disorder that involves cerebral and cerebellar abnormalities. The cerebellum plays an indispensable role in the pathophysiology of SZ. However, individual studies pertaining to the structural and resting-state functional cerebellar abnormalities in patients with SZ have been inconsistent. To make a relatively robust conclusion with little interference, such as different disease episode times and antipsychotic treatment, we conducted this meta-analysis as a first attempt to comprehensively analyze and combine studies of voxel-based morphometry (VBM), amplitude of low-frequency fluctuation (ALFF), and functional connectivity strength (FCS) in first-episode and drug-naive SZ patients, employing the Seed-based d Mapping (SDM) method. Thirteen VBM studies, eight ALFF studies, and three FCS studies involving 783 patients and 704 matched healthy controls were included. Our results showed the presence of structural and functional abnormalities within the cerebellar regions, including most superior/anterior cerebellum (lobule III-V or VI) and posterior/inferior cerebellum (lobule VIII) related to motor function, and posterior cerebellum (lobule VIIa, Crus I, and II) associated with cognition and emotion, and such anomalies might be related to illness duration and clinical symptom severity.

PMID: 30500474 [PubMed - as supplied by publisher]

Combining resting state functional MRI with intraoperative cortical stimulation to map the mentalizing network.

Tue, 12/04/2018 - 13:20
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Combining resting state functional MRI with intraoperative cortical stimulation to map the mentalizing network.

Neuroimage. 2018 Nov 27;:

Authors: Yordanova YN, Cochereau J, Duffau H, Herbet G

Abstract
OBJECTIVE: To infer the face-based mentalizing network from resting-state functional MRI (rsfMRI) using a seed-based correlation analyses with regions of interest identified during intraoperative cortical electrostimulation.
METHODS: We retrospectively included 23 patients in whom cortical electrostimulation induced transient face-based mentalizing impairment during 'awake' craniotomy for resection of a right-sided diffuse low-grade glioma. Positive stimulation sites were recorded and transferred to the patients' preoperative normalized MRI, and then used as seeds for subsequent seed-to-voxel functional connectivity analyses. The analyses, conducted with an uncorrected voxel-level p-value of 0.001 and a false-discovery-rate cluster-level p-value of 0.05, allowed identification of the cortical structures, functionally coupled with the mentalizing-related sites.
RESULTS: Two clusters of responsive stimulations were identified intraoperatively - one in the right dorsolateral prefrontal cortex (dlPFC, n = 13) and the other in the right inferior frontal gyrus (IFG, n = 10). A whole group level analysis revealed that stimulation sites correlated mainly with voxels located in the pars triangularis of the IFG, the dorsolateral and dorsomedial prefrontal cortices, the temporo-parietal junction, the posterior superior temporal sulcus, and the posterior inferior temporal/fusiform gyrus. Other analyses, taking into consideration the location of the responsive sites (IFG versus dlPFC cluster), highlighted only minor differences between both groups.
CONCLUSIONS: The present study successfully demonstrated the involvement of a large-scale neural network in the face-based mentalizing that perfectly matches networks, classically identified using task-based fMRI paradigms. We thus validated the combination of rsfMRI and stimulation mapping as a powerful approach to identify functional networks in brain-damaged patients.

PMID: 30500423 [PubMed - as supplied by publisher]

Dual-contrast pCASL using simultaneous gradient-echo/spin-echo multiband EPI.

Tue, 12/04/2018 - 13:20
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Dual-contrast pCASL using simultaneous gradient-echo/spin-echo multiband EPI.

Magn Reson Imaging. 2018 Nov 27;:

Authors: Zhang K, Sturm VJ, Buschle LR, Hahn A, Yun SD, Jon Shah N, Bendszus M, Heiland S, Schlemmer HP, Ziener CH, Kurz FT

Abstract
A 2D gradient-echo EPI is commonly employed for arterial spin labeling (ASL) readout to achieve fast whole brain coverage measurements. However, such a readout suffers from susceptibility artifacts induced by magnetic field inhomogeneities. To reduce these susceptibility effects, single-shot spin-echo EPI was proposed to be used for acquisitions in continuous ASL (CASL). To minimize functional and physiological variations, a gradient-echo (GE)/spin-echo (SE) dual-echo EPI readout of the CASL sequence is needed for a comparison between GE- and SE-based determination of cerebral blood flow (CBF). In this study, we employed a simultaneous GE/SE multiband EPI as the readout of a pseudo-CASL (pCASL) sequence. Motor cortex activations derived from a finger-tapping task and functional networks from resting state fMRI were compared for both GE and SE contrasts. Direct comparison of SE and GE contrasts revealed that GE ASL provides an improved sensitivity of functional activity in finger-tapping and in resting-state imaging. SE ASL, on the other hand, suffered less from susceptibility artifacts induced by magnetic field inhomogeneities and pulsatile flow artifacts.

PMID: 30500347 [PubMed - as supplied by publisher]

Measuring abnormal intrinsic brain activities in patients with retinal detachment using amplitude of low-frequency fluctuation: a resting-state fMRI study.

Sat, 12/01/2018 - 22:40

Measuring abnormal intrinsic brain activities in patients with retinal detachment using amplitude of low-frequency fluctuation: a resting-state fMRI study.

Int J Neurosci. 2018 Nov 30;:1-13

Authors: Kang HH, Shu YQ, Yang L, Zhu PW, Li D, Li QH, Min YL, Ye L, Zhou Q, Shao Y

Abstract
OBJECTIVE: The targets of this study was to access the alternations of spontaneous brain activity in RD patients by amplitude of low-frequency fluctuation (ALFF) method and to explore their relationships with clinical behavioral performance.
METHODS: 20 patients with RD (6 males and 14 females), and 20 healthy controls (HCs) (6 males and 14 females) were recruited, and were matched in sex and age. All participants finished the functional magnetic resonance imaging (fMRI) scanning. We applied the ALFF method to detect the spontaneous brain activity. Receiver operating characteristic (ROC) curve was applied to distinguish RD Patients from HCs.
RESULTS: RD patients showed decreased ALFF values in the right occipital lobe and right medial frontal gyrus and increased ALFF values in the right frontal superior orbital and left inferior temporal gyrus when compared with HCs. In RD patients, we did not find any relationship between the mean ALFF values and the clinical behavioral performances.
CONCLUSION: The RD patients exhibited abnormal spontaneous brain activity in vision and vision related brain regions, which might explore potential pathological mechanism of acute vision loss in RD patients.

PMID: 30499735 [PubMed - as supplied by publisher]

Altered intrinsic local activity and cognitive dysfunction in HIV patients: A resting-state fMRI study.

Fri, 11/30/2018 - 21:20

Altered intrinsic local activity and cognitive dysfunction in HIV patients: A resting-state fMRI study.

PLoS One. 2018;13(11):e0207146

Authors: Bak Y, Jun S, Choi JY, Lee Y, Lee SK, Han S, Shin NY

Abstract
PURPOSE: To characterize resting-state brain activation patterns and investigate altered areas for cognitive decline in HIV patients.
METHODS: Twelve male HIV patients with intact cognition (HIV-IC), 10 with HIV-associated neurocognitive disorder (HAND), and 11 male healthy controls (HC) underwent resting-state functional MRI (rsfMRI). Three rsfMRI values, regional homogeneity (ReHo), amplitude of low-frequency fluctuation (ALFF), and fractional ALFF (fALFF) were calculated and compared between groups. Correlation analyses were performed between rsfMRI values and neuropsychological tests.
RESULTS: rsfMRI analyses revealed decreased rsfMRI values in the frontal areas, and increases in the posterior brain regions for both HIV-IC and HAND compared to HC. When directly compared to HIV-IC, HAND showed lower fALFF in the orbitofrontal cortex and higher ReHo in the primary sensorimotor area. Additionally, decreased orbitofrontal fALFF, increased sensorimotor ReHo, and a larger difference between the two values were highly correlated with decreased verbal memory and executive function in HIV patients.
CONCLUSIONS: Regardless of cognitive status, altered local intrinsic activities were found in HIV patients. The orbitofrontal cortex and primary sensorimotor area were more disrupted in HAND relative to HIV-IC and correlated with behavioral performance, suggesting these areas are relevant to cognitive impairment in HIV patients.

PMID: 30496203 [PubMed - in process]

Tracking the development of functional connectomes for face processing.

Fri, 11/30/2018 - 21:20

Tracking the development of functional connectomes for face processing.

Brain Connect. 2018 Nov 29;:

Authors: Joseph JE, Vanderweyen D, Swearingen J, Vaughan B, Novo D, Zhu X, Gebreghzhabier M, Bonilha L, Bhatt R, Naselaris T, Dean B

Abstract
Face processing capacities become more specialized and advanced during development but neural underpinnings of these processes are not fully understood. The present study applied graph-theory based network analysis to task-negative (resting blocks) and task-positive (viewing faces) fMRI data in children (5-17 years) and adults (18-42 years) to test the hypothesis that development of a specialized network for face processing is driven by task-positive processing (face viewing) more than by task-negative processing (visual fixation) and by both progressive and regressive changes in network properties. Predictive modeling was used to predict age from node-based network properties derived from task-positive and task-negative states in a whole-brain network and a canonical face network. The best fitting model indicated that face network maturation was marked by both progressive and regressive changes in information diffusion (eigenvector centrality) in the task-positive state, with regressive changes outweighing progressive changes. Hence, face network maturation was characterized by reductions in information diffusion potentially reflecting the development of more specialized modules. In contrast, whole-brain network maturation was marked by a balance of progressive and regressive changes in hub-connectivity (betweenness centrality) in the task-negative state. These findings suggest that development of specialized networks like the face network depend on dynamic developmental changes associated with domain-specific information (e.g., face processing) but maturation of the brain as whole can be predicted from task-free states.

PMID: 30489152 [PubMed - as supplied by publisher]

Vascular effects of caffeine found in BOLD fMRI.

Fri, 11/30/2018 - 21:20

Vascular effects of caffeine found in BOLD fMRI.

J Neurosci Res. 2018 Nov 29;:

Authors: Yang HS, Liang Z, Yao JF, Shen X, Frederick BD, Tong Y

Abstract
The blood oxygen level-dependent (BOLD) signal in functional magnetic resonance imaging (fMRI) measures neuronal activation indirectly. Previous studies have found aperiodic, systemic low-frequency oscillations (sLFOs, ~0.1 Hz) in BOLD signals from resting state (RS) fMRI, which reflects the non-neuronal cerebral perfusion information. In this study, we investigated the possibility of extracting vascular information from the sLFOs in RS BOLD fMRI, which could provide complementary information to the neuronal activations. Two features of BOLD signals were exploited. First, time delays between the sLFOs of big blood vessels and brain voxels were calculated to determine cerebral circulation times and blood arrival times. Second, voxel-wise standard deviations (SD) of LFOs were calculated to represent the blood densities. We explored those features on the publicly available Myconnectome data set (a 2-year study of an individual subject (Male)), which contains 45 RS scans acquired after the subject had coffee, and 45 coffee-free RS scans, acquired on different days. Our results showed that shorter time delays and smaller SDs were detected in caffeinated scans. This is consistent with the vasoconstriction effects of caffeine, which leads to increased blood flow velocity. We also compared our results with previous findings on neuronal networks from the same data set. Our finding showed that brain regions with the significant vascular effect of caffeine coincide with those with a significant neuronal effect, indicating close interaction. This study provides methods to assess the physiological information from RS fMRI. Together with the neuronal information, we can study simultaneously the underlying correlations and interactions between vascular and neuronal networks, especially in pharmacological studies.

PMID: 30488978 [PubMed - as supplied by publisher]

Resting-state functional brain networks in adults with a new diagnosis of focal epilepsy.

Fri, 11/30/2018 - 21:20
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Resting-state functional brain networks in adults with a new diagnosis of focal epilepsy.

Brain Behav. 2018 Nov 28;:e01168

Authors: Alonazi BK, Keller SS, Fallon N, Adams V, Das K, Marson AG, Sluming V

Abstract
OBJECTIVES: Newly diagnosed focal epilepsy (NDfE) is rarely studied, particularly using advanced neuroimaging techniques. Many patients with NDfE experience cognitive impairments, particularly with respect to memory, sustained attention, mental flexibility, and executive functioning. Cognitive impairments have been related to alterations in resting-state functional brain networks in patients with neurological disorders. In the present study, we investigated whether patients with NDfE had altered connectivity in large-scale functional networks using resting-state functional MRI.
METHODS: We recruited 27 adults with NDfE and 36 age- and sex-matched healthy controls. Resting-state functional MRI was analyzed using the Functional Connectivity Toolbox (CONN). We investigate reproducibly determined large-scale functional networks, including the default mode, salience, fronto-parietal attention, sensorimotor, and language networks using a seed-based approach. Network comparisons between patients and controls were thresholded using a FDR cluster-level correction approach.
RESULTS: We found no significant differences in functional connectivity between seeds within the default mode, salience, sensorimotor, and language networks and other regions of the brain between patients and controls. However, patients with NDfE had significantly reduced connectivity between intraparietal seeds within the fronto-parietal attention network and predominantly frontal and temporal cortical regions relative to controls; this finding was demonstrated including and excluding the patients with brain lesions. No common alteration in brain structure was observed in patients using voxel-based morphometry. Findings were not influenced by treatment outcome at 1 year.
CONCLUSIONS: Patients with focal epilepsy have brain functional connectivity alterations at diagnosis. Functional brain abnormalities are not necessarily a consequence of the chronicity of epilepsy and are present when seizures first emerge.

PMID: 30488645 [PubMed - as supplied by publisher]

Decreased Functional Connectivity in Insular Subregions in Depressive Episodes of Bipolar Disorder and Major Depressive Disorder.

Fri, 11/30/2018 - 21:20
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Decreased Functional Connectivity in Insular Subregions in Depressive Episodes of Bipolar Disorder and Major Depressive Disorder.

Front Neurosci. 2018;12:842

Authors: Yin Z, Chang M, Wei S, Jiang X, Zhou Y, Cui L, Lv J, Wang F, Tang Y

Abstract
Objective: Clinically, it is very difficult to distinguish between major depressive disorder (MDD) and bipolar disorder (BD) in the period of depression. Increasing evidence shows that the insula plays an important role in depression. We aimed to compare the resting-state functional connectivity (rsFC) of insular subregions in patients with MDD and BD in depressive episodes (BDD), who had never experienced manic or hypomanic episodes when they were scanned to identify biomarkers for the identification of two diseases. Methods: We recruited 21 BDD patients, 40 MDD patients and 70 healthy controls (HC). Resting-state functional magnetic resonance imaging (rs-fMRI) was performed. BDD patients had never had manic or hypomanic episodes when they were scanned, and the diagnoses were determined by follow-up. We divided the insula into three parts including the ventral anterior insular cortex (v-AIN), dorsal anterior insular cortex (d-AIN), and posterior insula (PI). The insular-based rsFC was compared among the three groups, and an analysis of the correlation between the rsFC value and Hamilton depression and anxiety scales was carried out. Results: BDD and MDD patients demonstrated decreased rsFC from the v-AIN to the left superior/middle frontal gyrus compared with the HC group. Versus MDD and HC groups, BDD patients exhibited decreased rsFC from the v-AIN to the area in the left orbital frontal gyrus and left superior temporal gyrus (included temporal pole), from the PI to the right lateral postcentral gyrus and from all three insular subregions to the somatosensory and motor cortex. Meanwhile, a correlation between the rsFC value of the PI-right lateral postcentral gyrus and anxiety score was observed in patients. Conclusion: Our findings show BDD and MDD patients have similar decreases in insular connectivity in the dorsal lateral frontal regions, and BDD patients have specific decreased insular connectivity, especially in the somatosensory and motor cortex, which may be used as imaging evidence for clinical identification.

PMID: 30487732 [PubMed]

Short-term Sahaja Yoga meditation training modulates brain structure and spontaneous activity in the executive control network.

Fri, 11/30/2018 - 21:20
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Short-term Sahaja Yoga meditation training modulates brain structure and spontaneous activity in the executive control network.

Brain Behav. 2018 Nov 28;:e01159

Authors: Dodich A, Zollo M, Crespi C, Cappa SF, Laureiro Martinez D, Falini A, Canessa N

Abstract
INTRODUCTION: While cross-sectional studies have shown neural changes in long-term meditators, they might be confounded by self-selection and potential baseline differences between meditators and non meditators. Prospective longitudinal studies of the effects of meditation in naïve subjects are more conclusive with respect to causal inferences, but related evidence is so far limited.
METHODS: Here, we assessed the effects of a 4-week Sahaja Yoga meditation training on gray matter density and spontaneous resting-state brain activity in a group of 12 meditation-naïve healthy adults.
RESULTS: Compared with 30 control subjects, the participants to meditation training showed increased gray matter density and changes in the coherence of intrinsic brain activity in two adjacent regions of the right inferior frontal gyrus encompassing the anterior component of the executive control network. Both these measures correlated with self-reported well-being scores in the meditation group.
CONCLUSIONS: The significant impact of a brief meditation training on brain regions associated with attention, self-control, and self-awareness may reflect the engagement of cognitive control skills in searching for a state of mental silence, a distinctive feature of Sahaja Yoga meditation. The manifold implications of these findings involve both managerial and rehabilitative settings concerned with well-being and emotional state in normal and pathological conditions.

PMID: 30485713 [PubMed - as supplied by publisher]

Low rank and sparsity constrained method for identifying overlapping functional brain networks.

Fri, 11/30/2018 - 21:20
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Low rank and sparsity constrained method for identifying overlapping functional brain networks.

PLoS One. 2018;13(11):e0208068

Authors: Aggarwal P, Gupta A

Abstract
Analysis of functional magnetic resonance imaging (fMRI) data has revealed that brain regions can be grouped into functional brain networks (fBNs) or communities. A community in fMRI analysis signifies a group of brain regions coupled functionally with one another. In neuroimaging, functional connectivity (FC) measure can be utilized to quantify such functionally connected regions for disease diagnosis and hence, signifies the need of devising novel FC estimation methods. In this paper, we propose a novel method of learning FC by constraining its rank and the sum of non-zero coefficients. The underlying idea is that fBNs are sparse and can be embedded in a relatively lower dimension space. In addition, we propose to extract overlapping networks. In many instances, communities are characterized as combinations of disjoint brain regions, although recent studies indicate that brain regions may participate in more than one community. In this paper, large-scale overlapping fBNs are identified on resting state fMRI data by employing non-negative matrix factorization. Our findings support the existence of overlapping brain networks.

PMID: 30485369 [PubMed - in process]

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