New resting-state fMRI related studies at PubMed

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Spatio-Temporal Dynamics of Intrinsic Networks in Functional Magnetic Imaging Data Using Recurrent Neural Networks.

Tue, 10/09/2018 - 13:40
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Spatio-Temporal Dynamics of Intrinsic Networks in Functional Magnetic Imaging Data Using Recurrent Neural Networks.

Front Neurosci. 2018;12:600

Authors: Hjelm RD, Damaraju E, Cho K, Laufs H, Plis SM, Calhoun VD

Abstract
We introduce a novel recurrent neural network (RNN) approach to account for temporal dynamics and dependencies in brain networks observed via functional magnetic resonance imaging (fMRI). Our approach directly parameterizes temporal dynamics through recurrent connections, which can be used to formulate blind source separation with a conditional (rather than marginal) independence assumption, which we call RNN-ICA. This formulation enables us to visualize the temporal dynamics of both first order (activity) and second order (directed connectivity) information in brain networks that are widely studied in a static sense, but not well-characterized dynamically. RNN-ICA predicts dynamics directly from the recurrent states of the RNN in both task and resting state fMRI. Our results show both task-related and group-differentiating directed connectivity.

PMID: 30294250 [PubMed]

Abnormal Functional Connectivity Density in Post-Stroke Aphasia.

Mon, 10/08/2018 - 12:40
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Abnormal Functional Connectivity Density in Post-Stroke Aphasia.

Brain Topogr. 2018 Oct 06;:

Authors: Guo J, Yang M, Biswal BB, Yang P, Liao W, Chen H

Abstract
Post-stroke aphasia (PSA), which refers to the loss or impairment of language, is typically caused by left hemisphere lesions. Previous neuroimaging studies have indicated that the pathology of PSA may be related to abnormalities in functional integration. In this study, we used resting-state functional magnetic resonance imaging (rs-fMRI) to examine functional connectivity density (FCD) in PSA. We compared short- and long-range FCD between individuals with PSA (n = 17) and healthy controls (HC, n = 20). We then performed Pearson's correlation analysis on the FCD values from the affected brain regions and the speech scores in the PSA group. Compared with HCs, individuals with PSA showed increased short-range FCD in the contralesional temporal gyrus, the inferior frontal gyrus, the thalamus, the insula, and the mesial temporal gyrus [hippocampus/parahippocampus (HIP/ParaHIP)]. PSA demonstrated an increased long-range FCD in the contralesional mesial temporal gyrus (HIP/ParaHIP). PSA also displayed decreased short-range FCD in the ipsilesional part of the frontal gyrus, the caudate, the thalamus, the fusiform gyrus, and the mesial temporal gyrus (HIP/ParaHIP), and decreased long-range FCD in the ipsilesional superior temporal gyrus, the fusiform gyrus, and the mesial temporal gyrus (HIP/ParaHIP). The decreased long-range FCD in the left superior temporal gyrus in PSA subjects was positively correlated with the spontaneous speech score. The altered FCD observed due to disrupted functional connectivity after stroke may lead to language production, semantic processing, and cognitive impairments. Our findings expand previous functional studies on stroke and provide new evidence of the intraregional and interregional interactions at the voxel level in the pathophysiology of PSA.

PMID: 30293180 [PubMed - as supplied by publisher]

Preschool Executive Function Predicts Childhood Resting-State Functional Connectivity and Attention-Deficit/Hyperactivity Disorder and Depression.

Mon, 10/08/2018 - 12:40
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Preschool Executive Function Predicts Childhood Resting-State Functional Connectivity and Attention-Deficit/Hyperactivity Disorder and Depression.

Biol Psychiatry Cogn Neurosci Neuroimaging. 2018 Jul 21;:

Authors: Hawkey EJ, Tillman R, Luby JL, Barch DM

Abstract
BACKGROUND: Measures of executive function (EF), such as the Behavior Rating Inventory of Executive Function, distinguish children with attention-deficit/hyperactivity disorder (ADHD) from control subjects, but less work has examined relationships to depression or brain network organization. This study examined whether early childhood EF predicted new onset or worsening of ADHD and/or depression and examined how early childhood EF related to functional connectivity of brain networks at school age.
METHODS: Participants included 247 children who were enrolled at 3 to 6 years of age from a prospective study of emotion development. The Behavior Rating Inventory of Executive Function Global Executive Composite score was used as the measure of EF in early childhood to predict ADHD and depression diagnoses and symptoms across school age. Resting-state functional magnetic resonance imaging network analyses examined global efficiency in the frontoparietal, cingulo-opercular, salience, and default mode networks and six "hub" seed regions selected to examine between-network connectivity.
RESULTS: Early childhood EF predicted new onset and worsening of ADHD and depression symptoms across school age. Greater EF deficits in preschool predicted increased global efficiency in the salience network and altered connectivity with four regions for the dorsal anterior cingulate cortex hub and one region with the insula hub at school age. This altered connectivity was related to increasing ADHD and depression symptoms.
CONCLUSIONS: Early executive deficits may be an early common liability for risk of developing ADHD and/or depression and were associated with altered functional connectivity in networks and hub regions relevant to executive processes. Future work could help clarify whether specific EF deficits are implicated in the development of both disorders.

PMID: 30292809 [PubMed - as supplied by publisher]

Alterations in Resting-State Networks Following In Utero Selective Serotonin Reuptake Inhibitor Exposure in the Neonatal Brain.

Mon, 10/08/2018 - 12:40
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Alterations in Resting-State Networks Following In Utero Selective Serotonin Reuptake Inhibitor Exposure in the Neonatal Brain.

Biol Psychiatry Cogn Neurosci Neuroimaging. 2018 Aug 25;:

Authors: Rotem-Kohavi N, Williams LJ, Virji-Babul N, Bjornson BH, Brain U, Werker JF, Grunau RE, Miller SP, Oberlander TF

Abstract
BACKGROUND: Selective serotonin reuptake inhibitors (SSRIs) are commonly used to treat depression during pregnancy. SSRIs cross the placenta, inhibit serotonin reuptake, and thereby are thought to alter central fetal serotonin signaling. Both prenatal maternal mood disturbances and in utero SSRI exposure have been associated with altered fetal and infant behavior. Resting-state functional magnetic resonance imaging has identified resting-state networks (RSNs) in newborns, reflecting functional capacity of auditory and visual networks and providing opportunities to examine early experiences effects on neurodevelopment. We sought to examine the effect of in utero SSRI exposure on neonatal RSN functional organization. We hypothesized that prenatal SSRI exposure would be associated with alterations in neonatal RSNs compared with healthy control infants and infants exposed to mothers with depression.
METHODS: Clinician-rated Hamilton Depression Rating Scale and self-reported Pregnancy Experiences Scale were completed during the third trimester. Control (n = 17), maternal depression-exposed (Hamilton Depression Rating Scale ≥8 without SSRI exposure, n = 16), and SSRI-exposed (n = 20) 6-day-old neonates underwent resting-state functional magnetic resonance imaging. Independent component analysis was used as a data-driven approach to extract 22 RSNs.
RESULTS: SSRI-exposed neonates had higher connectivity in a putative auditory RSN compared with depressed-only (p = .01) and control (p = .02) infants (corrected for multiple comparisons), controlling for sex, age at the magnetic resonance imaging, and Pregnancy Experiences Scale score.
CONCLUSIONS: Hyperconnectivity in auditory RSN in neonates with in utero SSRI exposure relative to neonates of depressed but not pharmacologically treated mothers and control infants may offer an insight into the functional organization origins of shifts in language perception and altered language development, previously reported in infants and children with prenatal SSRI exposure.

PMID: 30292808 [PubMed - as supplied by publisher]

Evaluation of the prognosis in severe traumatic brain injury patients using resting-state fMRI.

Sun, 10/07/2018 - 11:20

Evaluation of the prognosis in severe traumatic brain injury patients using resting-state fMRI.

World Neurosurg. 2018 Oct 03;:

Authors: Guo H, Liu R, Sun Z, Liu B, Xiang Y, Mao J, Li G, Zhang M

Abstract
BACKGROUND: Our study is aimed to investigate the change of the default-mode network (DMN) by using Amplitude of Low-Frequency Fluctuation (ALFF) and functional connectivity (FC) methods in acute phase patients after severe traumatic brain injury (sTBI) and to correlate these changes with its prognosis.
METHODS: Twenty one patients with severe traumatic brain injury were included in this study. Gender, age and education matched controls were participated in this study. Twenty-one healthy volunteers were recruited for the control group. Of 21 patients, 12 patients regained consciousness (GOS > 2) and 9 patients remained unconscious (GOS < 2). The FC and ALFF values were measured in DMN and compared between the groups. We further assessed and compared the FC and ALFF value in both group.
RESULTS: sTBI patients showed significantly decreased functional connectivity and ALFF values in the DMN. While, patient with better prognosis showed a significant increased in the functional connectivity and ALFF values in DMN. The conscious subgroup showed significantly enhanced functional connectivity in the medial superior frontal gyrus, left temporal gyrus, anterior cingulate gyrus, precuneus, posterior cingulate gyrus, and parietal cortex compared to the coma subgroup. Increased ALFF values in the right frontal gyrus, right temporal gyrus, and right inferior parietal gyrus was significantly showed in the conscious subgroup compared to the coma subgroup.
CONCLUSION: Increased in the functional connectivity and ALFF values in the DMN is related to better prognosis in patient with severe traumatic brain injury.

PMID: 30292041 [PubMed - as supplied by publisher]

Disrupted functional connectivity and activity in the white matter of the sensorimotor system in patients with pontine strokes.

Sun, 10/07/2018 - 11:20
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Disrupted functional connectivity and activity in the white matter of the sensorimotor system in patients with pontine strokes.

J Magn Reson Imaging. 2018 Oct 06;:

Authors: Wang J, Yang Z, Zhang M, Shan Y, Rong D, Ma Q, Liu H, Wu X, Li K, Ding Z, Lu J

Abstract
BACKGROUND: White matter (WM) blood oxygenation level-dependent (BOLD) signals are reported to be related to neural activity. However, sensitivity of WM BOLD signals to disease remains unclear.
PURPOSE: To investigate WM BOLD signal changes, directional variations of resting-state correlations in sensorimotor system in patients with pontine strokes, and to determine the relationship between WM BOLD signals and motor deficits.
STUDY TYPE: Prospective.
SUBJECTS: Ethical approval was obtained from the local Ethics Committee and each participant gave written informed consent. Sixteen patients with focal pontine lesions and 16 age-matched control subjects were included.
FIELD STRENGTH/SEQUENCE: 3.0T T1 -weighted anatomic images using a 3D magnetization-prepared rapid gradient-echo sequence. Resting-state fMRI images using gradient-echo echo-planar imaging sequence. Diffusion-weighted images using single-shot spin-echo diffusion echo-planar imaging.
ASSESSMENT: Relevant WM tracts in the sensorimotor system by region of interest-wise analysis were identified. Power spectra of BOLD signals and anisotropy of resting-state correlations were measured in sensorimotor system and compared between two groups. Their relationships with clinical scores were analyzed.
STATISTICAL TESTS: Two-sample t-test; partial correlation analysis.
RESULTS: Power spectra of BOLD signals in nerve tracts on the ipsilesional side were significantly decreased (P < 0.05). Compared with that in healthy subjects, the anisotropy of resting-state correlations along identified WM tracts was decreased in the thalamus-dorsolateral prefrontal cortex bundle on the contralesional side, and all nerve tracts on the ipsilesional side. Partial least squares regression analysis showed the predicted outcome scores correlated significantly with actual Fugl-Meyer scores (R2  = 0.944, P = 0.013).
DATA CONCLUSION: Our findings suggest that disrupted activity and functional connectivity in WM areas of the sensorimotor system can be detected in pontine strokes, and may serve as a biomarker for motor function prediction.
LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018.

PMID: 30291655 [PubMed - as supplied by publisher]

Neural networks of aggression: ALE meta-analyses on trait and elicited aggression.

Sun, 10/07/2018 - 11:20
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Neural networks of aggression: ALE meta-analyses on trait and elicited aggression.

Brain Struct Funct. 2018 Oct 05;:

Authors: Wong TY, Sid A, Wensing T, Eickhoff SB, Habel U, Gur RC, Nickl-Jockschat T

Abstract
There is considerable evidence that emotion dysregulation and self-control impairments lead to escalated aggression in populations with psychiatric disorders. However, convergent quantitative evidence on the neural network explaining how aggression arises is still lacking. To address this gap, peak activations extracted from extant functional magnetic resonance imaging (fMRI) studies were synthesized through coordinate-based meta-analyses. A systematic search in the PubMed database was conducted and 26 fMRI studies met the inclusion criteria. Three separate activation likelihood estimation (ALE) meta-analyses were performed on (1) individual differences in trait aggression (TA) studies, (2) individual differences in TA studies examining executive functioning, and (3) elicited aggression (EA) studies across fMRI behavioral paradigms. Ensuing clusters from ALE meta-analyses were further treated as seeds for follow-up investigations on consensus connectivity networks (CCN) delineated from meta-analytic connectivity modeling (MACM) and resting-state functional connectivity (RSFC) to further characterize their physiological functions. Finally, we obtained a data-driven functional characterization of the ensuing clusters and their networks. This approach offers a boarder view of the ensuing clusters using a boarder network perspective. In TA, aberrant brain activations were found only in the right precuneus. Follow-up analyses revealed that the precuneus seed was within the frontal-parietal network (FPN) associated with action inhibition, visuospatial processing and higher-level cognition. With further restricting to only experiments examining executive functioning, convergent evidence was found in the right rolandic operculum (RO), midcingulate cortex (MCC), precentral gyrus (PrG) and precuneus. Follow-up analyses suggested that RO, MCC and PrG may belong to a common cognitive control network, while the MCC seems to be the hub of this network. In EA, we only revealed a convergent region in the left postcentral gyrus. Follow-up CCN analyses and functional characterizations suggested that this region may also belong to the same cognitive control network found in the TA sub-analysis. Our results suggested that escalated aggression arises from abnormal precuneus activities within the FPN, disrupting the recruitment of other large-scale networks such as adaptive cognitive control network. Consequently, failure to recruit such a network results in an inability to generate adaptive responses, increasing the likelihood of acting aggressively.

PMID: 30291479 [PubMed - as supplied by publisher]

Impact of FAAH genetic variation on fronto-amygdala function during emotional processing.

Sun, 10/07/2018 - 11:20
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Impact of FAAH genetic variation on fronto-amygdala function during emotional processing.

Eur Arch Psychiatry Clin Neurosci. 2018 Oct 05;:

Authors: Gärtner A, Dörfel D, Diers K, Witt SH, Strobel A, Brocke B

Abstract
Recent translational studies identified a common endocannabinoid polymorphism, FAAH C385A, in the gene for the fatty acid amide hydrolase (FAAH). This polymorphism alters endocannabinoid anandamide levels, which are known to be involved in the fronto-amygdala circuitry implicated in mood regulation and anxiety-like behaviors. While it has been shown that the variant that selectively enhances fronto-amygdala connectivity at rest is associated with decreased anxiety-like behaviors, no study so far has investigated whether this finding of FAAH-related differential plasticity extends to task-related differential functional expression and regulation during negative emotional processing. Using an imaging genetics approach, this study aimed to replicate and extend prior findings by examining functional activity and task-related connectivity in fronto-amygdala regions during emotion reactivity and emotional down-regulation of negative affect. Therefore, 48 healthy young adults underwent a functional MRI resting state measurement, completed an emotion regulation paradigm and provided self-reports on anxiety and use of emotion regulation strategies. In line with previous studies, preliminary evidence suggests that A-allele carriers demonstrate stronger fronto-amygdala connectivity during rest. In addition, exploratory whole-brain analyses indicate differential functional activity of A-allele carriers during emotion reactivity and emotion regulation. There were no associations with anxiety-related self-reports and use of emotional regulation strategies. Further research using larger samples and polygenic approaches is indicated to clarify the precise role and its underlying mechanisms in emotion processing.

PMID: 30291441 [PubMed - as supplied by publisher]

A network view on brain regions involved in experts' object and pattern recognition: Implications for the neural mechanisms of skilled visual perception.

Sun, 10/07/2018 - 11:20
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A network view on brain regions involved in experts' object and pattern recognition: Implications for the neural mechanisms of skilled visual perception.

Brain Cogn. 2018 Oct 02;:

Authors: Langner R, Eickhoff SB, Bilalić M

Abstract
Skilled visual object and pattern recognition form the basis of many everyday behaviours. The game of chess has often been used as a model case for studying how long-term experience aides in perceiving objects and their spatio-functional interrelations. Earlier research revealed two brain regions, posterior middle temporal gyrus (pMTG) and collateral sulcus (CoS), to be linked to chess experts' superior object and pattern recognition, respectively. Here we elucidated the brain networks these two expertise-related regions are embedded in, employing resting-state functional connectivity analysis and meta-analytic connectivity modelling with the BrainMap database. pMTG was preferentially connected with dorsal visual stream areas and a parieto-prefrontal network for action planning, while CoS was preferentially connected with posterior medial cortex and hippocampus, linked to scene perception, perspective-taking and navigation. Functional profiling using BrainMap meta-data revealed that pMTG was linked to semantic processing as well as inhibition and attention, while CoS was linked to face and shape perception as well as passive viewing. Our findings suggest that pMTG subserves skilled object recognition by mediating the link between object identity and object affordances, while CoS subserves skilled pattern recognition by linking the position of individual objects with typical spatio-functional layouts of their environment stored in memory.

PMID: 30290974 [PubMed - as supplied by publisher]

Network abnormalities in generalized anxiety pervade beyond the amygdala-pre-frontal cortex circuit: Insights from graph theory.

Sat, 10/06/2018 - 10:20

Network abnormalities in generalized anxiety pervade beyond the amygdala-pre-frontal cortex circuit: Insights from graph theory.

Psychiatry Res Neuroimaging. 2018 Sep 27;281:107-116

Authors: Makovac E, Mancini M, Fagioli S, Watson DR, Meeten F, Rae CL, Critchley HD, Ottaviani C

Abstract
Generalized anxiety disorder (GAD) has excessive anxiety and uncontrollable worry as core symptoms. Abnormal cerebral functioning underpins the expression and perhaps pathogenesis of GAD:. Studies implicate impaired communication between the amygdala and the pre-frontal cortex (PFC). Our aim was to longitudinally investigate whether such network abnormalities are spatially restricted to this circuit or if the integrity of functional brain networks is globally disrupted in GAD. We acquired resting-state functional magnetic resonance imaging data from 16 GAD patients and 16 matched controls at baseline and after 1 year. Using network modeling and graph-theory, whole-brain connectivity was characterized from local and global perspectives. Overall lower global efficiency, indicating sub-optimal brain-wide organization and integration, was present in patients with GAD compared to controls. The amygdala and midline cortices showed higher betweenness centrality, reflecting functional dominance of these brain structures. Third, lower betweenness centrality and lower degree emerged for PFC, suggesting weakened inhibitory control. Overall, network organization showed impairments consistent with neurobiological models of GAD (involving amygdala, PFC, and cingulate cortex) and further pointed to an involvement of temporal regions. Such impairments tended to progress over time and predict anxiety symptoms. A graph-analytic approach represents a powerful approach to deepen our understanding of GAD.

PMID: 30290286 [PubMed - as supplied by publisher]

COMBINING PHENOTYPIC AND RESTING-STATE FMRI DATA FOR AUTISM CLASSIFICATION WITH RECURRENT NEURAL NETWORKS.

Sat, 10/06/2018 - 10:20
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COMBINING PHENOTYPIC AND RESTING-STATE FMRI DATA FOR AUTISM CLASSIFICATION WITH RECURRENT NEURAL NETWORKS.

Proc IEEE Int Symp Biomed Imaging. 2018 Apr;2018:725-728

Authors: Dvornek NC, Ventola P, Duncan JS

Abstract
Accurate identification of autism spectrum disorder (ASD) from resting-state functional magnetic resonance imaging (rsfMRI) is a challenging task due in large part to the heterogeneity of ASD. Recent work has shown better classification accuracy using a recurrent neural network with rsfMRI time-series as inputs. However, phenotypic features, which are often available and likely carry predictive information, are excluded from the model, and combining such data with rsfMRI into the recurrent neural network is not a straightforward task. In this paper, we present several methodologies for incorporating phenotypic data with rsfMRI into a single deep learning framework for classifying ASD. We test the proposed architectures using a cross-validation framework on the large, heterogeneous first cohort from the Autism Brain Imaging Data Exchange. Our best model achieved an accuracy of 70.1%, outperforming prior work.

PMID: 30288208 [PubMed]

Community and household-level socioeconomic disadvantage and functional organization of the salience and emotion network in children and adolescents.

Sat, 10/06/2018 - 10:20
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Community and household-level socioeconomic disadvantage and functional organization of the salience and emotion network in children and adolescents.

Neuroimage. 2018 Oct 01;:

Authors: Gellci K, Marusak HA, Peters C, Elrahal F, Iadipaolo AS, Rabinak CA

Abstract
Socioeconomic disadvantage (SED) during childhood has been linked to disparities in physical and mental health. A growing body of research has focused on identifying neurodevelopmental consequences of SED, commonly measured using within-household factors (e.g., household income), to better understand the processes underlying SED-related disparities. These studies suggest that childhood SED has a widespread impact on brain development, altering development of multiple brain regions simultaneously. These findings also raise the possibility that childhood SED impacts development of key brain systems, such as the salience and emotion network (SEN), which is positioned at the intersection of brain systems involved in cognitive and emotion-related functioning and is thought to mediate information flow within and between these networks. The present study tests for associations between household- and community-level SED, as well as their interaction, and measures of SEN-based functional neural organization in 57 children and adolescents (ages 6-17). We applied graph theoretical analyses to resting-state functional magnetic resonance imaging (fMRI) to examine SEN-based functional network topology. Results showed that youth residing in more distressed communities demonstrate lower hub-like properties (i.e., less efficient global information transfer and fewer connections) of two core SEN nodes - the anterior cingulate cortex and the left supramarginal gyrus. Household income had an opposite effect on efficiency of the anterior cingulate, but no effect on the supramarginal gyrus. There was, however, an interaction between income and community SED in the rostral prefrontal cortex, such that higher income was associated with higher clustering coefficient and lower betweenness centrality, suggesting greater local processing and lower influence of this region on information flow across the network. These effects were significant only among youth living in low (but not high) SED communities, suggesting that within-household SED factors may not protect against the detrimental effects of a disadvantaged community context. Similarly, the age-related increase in average path length of the left rostral prefrontal cortex was only significant among youth living in low (but not high) SED communities. Given that maturation of the SEN is considered to be a critical functional backbone supporting the development of more flexible cognitive and emotional processes into adulthood, we tested for links between SEN graph metrics and measures of cognitive and emotion-related functioning. We found that higher community SED and lower income were both associated with lower IQ. Lower IQ, in turn, was associated with global efficiency of the left supramarginal gyrus. Observed effects of SED on SEN-based functional neural organization may help to explain the strong and pervasive link between childhood SED and disparities in cognitive and emotional outcomes.

PMID: 30287301 [PubMed - as supplied by publisher]

A dynamic system of brain networks revealed by fast transient EEG fluctuations and their fMRI correlates.

Sat, 10/06/2018 - 10:20
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A dynamic system of brain networks revealed by fast transient EEG fluctuations and their fMRI correlates.

Neuroimage. 2018 Oct 01;:

Authors: Hunyadi B, Woolrich M, Quinn A, Vidaurre D, De Vos M

Abstract
Resting state brain activity has become a significant area of investigation in human neuroimaging. An important approach for understanding the dynamics of neuronal activity in the resting state is to use complementary imaging modalities. Electrophysiological recordings can access fast temporal dynamics, while functional magnetic resonance imaging (fMRI) studies reveal detailed spatial patterns. However, the relationship between these two measures is not fully established. In this study, we used simultaneously recorded electroencephalography (EEG) and fMRI, along with Hidden Markov Modelling, to investigate how network dynamics at fast sub-second time-scales, accessible with EEG, link to the slower time-scales and higher spatial detail of fMRI. We found that the fMRI correlates of fast transient EEG dynamic networks show highly reproducible spatial patterns, and that their spatial organization exhibits strong similarity with traditional fMRI resting state networks maps. This further demonstrates the potential of electrophysiology as a tool for understanding the fast network dynamics that underlie fMRI resting state networks.

PMID: 30287299 [PubMed - as supplied by publisher]

Resting state functional connectivity in patients with remitted psychotic depression: A multi-centre STOP-PD study.

Sat, 10/06/2018 - 10:20
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Resting state functional connectivity in patients with remitted psychotic depression: A multi-centre STOP-PD study.

EBioMedicine. 2018 Oct 01;:

Authors: Neufeld NH, Mulsant BH, Dickie EW, Meyers BS, Alexopoulos GS, Rothschild AJ, Whyte EM, Hoptman MJ, Nazeri A, Downar J, Flint AJ, Voineskos AN

Abstract
BACKGROUND: There is paucity of neurobiological knowledge about major depressive disorder with psychotic features ("psychotic depression"). This study addresses this knowledge gap by using resting state functional magnetic resonance imaging (R-fMRI) to compare functional connectivity in patients with psychotic depression and healthy controls.
METHODS: We scanned patients who participated in a randomized controlled trial as well as healthy controls. All patients achieved remission from depressive and psychotic symptoms with sertraline and olanzapine. We employed Independent Component Analysis in independent samples to isolate the default mode network (DMN) and compared patients and controls.
FINDINGS: The Toronto sample included 28 patients (mean [SD], age 56·2 [13·7]) and 39 controls (age 55·1 [13·5]). The Replication sample included 29 patients (age 56·1 [17·7]) and 36 controls (age 48·3 [17·9]). Patients in the Toronto sample demonstrated decreased between-network functional connectivity between the DMN and bilateral insular, somatosensory/motor, and auditory cortices with peak activity in the right planum polare (t = 4·831; p = 0·001, Family Wise Error (FWE) corrected). A similar pattern of between-network functional connectivity was present in our Replication sample with peak activity in the right precentral gyrus (t = 4·144; p = 0·003, FWE corrected).
INTERPRETATION: Remission from psychotic depression is consistently associated with an absence of increased DMN-related functional connectivity and presence of decreased between-network functional connectivity. Future research will evaluate this abnormal DMN-related functional connectivity as a potential biomarker for treatment trajectories.
FUNDING: National Institute of Mental Health.

PMID: 30287158 [PubMed - as supplied by publisher]

Functional Disconnectivity during Inter-Task Resting State in Dementia with Lewy Bodies.

Sat, 10/06/2018 - 10:20
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Functional Disconnectivity during Inter-Task Resting State in Dementia with Lewy Bodies.

Dement Geriatr Cogn Disord. 2018;45(1-2):105-120

Authors: Chabran E, Roquet D, Gounot D, Sourty M, Armspach JP, Blanc F

Abstract
AIMS: Limited research has been done on the functional connectivity in visuoperceptual regions in dementia with Lewy bodies (DLB) patients. This study aimed to investigate the functional connectivity differences between a task condition and an inter-task resting state condition within a visuoperceptual paradigm, in DLB patients compared with Alzheimer disease (AD) patients and healthy elderly control subjects.
METHODS: Twenty-six DLB, 29 AD, and 22 healthy subjects underwent a detailed clinical and neuropsychological examination along with a functional MRI during the different conditions of a visuoperceptual paradigm. Functional images were analyzed using group-level spatial independent component analysis and seed-based connectivity analyses.
RESULTS: While the DLB patients scored well and did not differ from the control and AD groups in terms of functional activity and connectivity during the task conditions, they showed decreased functional connectivity in visuoperceptual regions during the resting state condition, along with a temporal impairment of the default-mode network activity. Functional connectivity disturbances were also found within two attentional-executive networks and between these networks and visuoperceptual regions.
CONCLUSION: We found a specific functional profile in the switching between task and resting state conditions in DLB patients. This result could help better characterize functional impairments in DLB and their contribution to several core symptoms of this pathology such as visual hallucinations and cognitive fluctuations.

PMID: 29723870 [PubMed - indexed for MEDLINE]

The Role of Amygdala in Patients With Euthymic Bipolar Disorder During Resting State.

Fri, 10/05/2018 - 15:40
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The Role of Amygdala in Patients With Euthymic Bipolar Disorder During Resting State.

Front Psychiatry. 2018;9:445

Authors: Li G, Liu P, Andari E, Zhang A, Zhang K

Abstract
The current study aims to explore the functional changes of the amygdala in patients with euthymic Bipolar Disorder (BD) using resting state fMRI (rs-fMRI). Twenty-one euthymic patients with bipolar disorder and 28 healthy controls participated in this study. Two of the euthymic patients with BD and three of the healthy controls were excluded due to excessive head motion. We found that patients with euthymia (38.79 ± 12.03) show higher fALFF (fractional Amplitude of low-frequency fluctuation) value of the amygdala (t = 2.076, P = 0.044), and lower functional connectivity between the amygdala and supplementary motor area (p < 0.01, GRF corrected) than healthy controls (33.40 ± 8.21). However, euthymic patients did not show a differential activity in ReHo (Regional Homogeneity) and gray matter of the amygdala region as compared to healthy controls. Thus, despite the absence of clinical symptoms in euthymic patients with BD, the amygdala functional activity and its connectivity to other brain regions remain altered. Further investigation of negative emotions and social functioning in euthymic patients with BD are needed and can help pave the way for a better understanding of BD psychopathology.

PMID: 30283367 [PubMed]

Resting-State Functional Connectivity of the Habenula in Mood Disorder Patients With and Without Suicide-Related Behaviors.

Fri, 10/05/2018 - 15:40
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Resting-State Functional Connectivity of the Habenula in Mood Disorder Patients With and Without Suicide-Related Behaviors.

J Neuropsychiatry Clin Neurosci. 2018 Oct 04;:appineuropsych17120351

Authors: Ambrosi E, Arciniegas DB, Curtis KN, Patriquin MA, Spalletta G, Sani G, Frueh BC, Fowler JC, Madan A, Salas R

Abstract
The habenula is a small midbrain structure that is important for brain signaling and learning from negative events. Thus, the habenula is strongly connected to both the reward system and motor regions. Increasing evidence suggests a role for the habenula in the etiology of psychiatric disorders, including mood and substance use disorders. However, no studies to date have investigated habenular resting-state functional connectivity (rsFC) in suicide-related behaviors (SB). The authors enrolled 123 individuals with major depressive disorder (MDD) or bipolar disorder and a history of suicide-related behaviors (SB+), 74 individuals with MDD or bipolar disorder and a history of suicidal ideation but no history of SB (SB-), and 75 healthy control subjects (HC). A seed-based approach was used to identify regions showing different rsFC with the habenula followed by region of interest to region of interest post hoc comparisons. Compared with both the SB- and HC groups, the SB+ group showed higher connectivity between the left habenula and the left parahippocampal gyrus, the right amygdala, and the right precentral and postcentral gyri. Patients with mood disorders displayed higher rsFC between the left habenula and left middle temporal gyrus, the left angular gyrus, and the left posterior cingulate cortex, as well as lower rsFC between the right habenula and the left thalamus, when compared with HCs. These findings suggest that the habenula is involved in the neural circuitry of suicide. The higher habenular rsFC found in the SB+ group may mediate a dysfunction in the mechanism that links the habenula with motor activity and contextual associative processing.

PMID: 30282513 [PubMed - as supplied by publisher]

Deep Learning Models Unveiled Functional Difference between Cortical Gyri and Sulci.

Thu, 10/04/2018 - 14:40
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Deep Learning Models Unveiled Functional Difference between Cortical Gyri and Sulci.

IEEE Trans Biomed Eng. 2018 Sep 28;:

Authors: Zhang S, Liu H, Huang H, Zhao Y, Jiang X, Bowers B, Guo L, Hu X, Sanchez M, Liu T

Abstract
It is largely unknown whether there is functional role difference between cortical gyral and sulcal regions. Recent advancements in neuroimaging studies demonstrate clear difference of structural connection profiles in gyral and sulcal areas, suggesting possible functional role difference in these convex and concave cortical regions. To explore and confirm such possible functional difference, we design and apply a powerful deep learning model of convolutional neural networks (CNN) that has been proven to be superior in learning discriminative and meaningful patterns on fMRI. By using the CNN model, gyral and sulcal fMRI signals are learned and predicted, and the prediction performance is adopted to demonstrate the functional difference between gyri and sulci. By using the Human Connectome Project (HCP) fMRI data and macaque brain fMRI data, an average of 83% and 90% classification accuracy has been achieved to separate gyral/sulcal HCP task fMRI signals at the population and individual subject level respectively; 81% and 86% classification accuracy for resting state fMRI signals at the group and individual subject level respectively. In addition, 78% classification accuracy has been achieved to separate gyral/sulcal resting state fMRI signals in macaque brains. Importantly, further analysis reveals that the discriminative features that are learned by CNNs to differentiate gyral/sulcal fMRI signals can be meaningfully interpreted, thus unveiling the fundamental functional difference between cortical gyri and sulci. That is, gyri are more global functional integration centers with simpler lower frequency signal components, while sulci are more local processing units with more complex higher frequency signal components.

PMID: 30281424 [PubMed - as supplied by publisher]

Altered Cervical Spinal Cord Resting State Activity in Fibromyalgia.

Thu, 10/04/2018 - 14:40
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Altered Cervical Spinal Cord Resting State Activity in Fibromyalgia.

Arthritis Rheumatol. 2018 Oct 03;:

Authors: Martucci KT, Weber KA, Mackey SC

Abstract
OBJECTIVE: Altered afferent input and central neural modulation are thought to contribute to fibromyalgia symptoms, and these processes converge within the spinal cord. We hypothesized that, using resting state functional magnetic resonance imaging (rs-fMRI) of the cervical spinal cord, we would observe altered frequency dependent activity in fibromyalgia.
METHODS: Cervical spinal cord rs-fMRI was performed in fibromyalgia patients and healthy controls. We analyzed a measure of low frequency oscillatory power, the amplitude of low frequency fluctuations (ALFF), for frequencies 0.01 - 0.198 Hz and frequency sub-bands, to determine regional and frequency-specific alterations in fibromyalgia. Functional connectivity and graph metrics were also analyzed.
RESULTS: As compared to controls, greater ventral and lesser dorsal Mean ALFF of the cervical spinal cord was observed in fibromyalgia (p < 0.05, uncorrected) for frequencies 0.01 - 0.198 Hz and all sub-bands. Additionally, lesser Mean ALFF within the right dorsal quadrant (p < 0.05, corrected) for frequencies 0.01 - 0.198 Hz and sub-band frequencies 0.073 - 0.198 Hz was observed in fibromyalgia. Regional Mean ALFF was not correlated with pain, however, regional lesser Mean ALFF was correlated with fatigue in patients (r = 0.763, p = 0.001). Functional connectivity and graph metrics were similar between groups.
CONCLUSION: Our results indicate unbalanced activity between the ventral and dorsal cervical spinal cord in fibromyalgia. Increased ventral neural processes and decreased dorsal neural processes may reflect the presence of central sensitization and contribute to fatigue and other bodily symptoms in fibromyalgia. This article is protected by copyright. All rights reserved.

PMID: 30281205 [PubMed - as supplied by publisher]

Altered Functional Connectivity of Alpha Rhythm in Obsessive-Compulsive Disorder During Rest.

Thu, 10/04/2018 - 14:40
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Altered Functional Connectivity of Alpha Rhythm in Obsessive-Compulsive Disorder During Rest.

Clin EEG Neurosci. 2018 Oct 03;:1550059418804378

Authors: Tan B, Liu Q, Wan C, Jin Z, Yang Y, Li L

Abstract
Obsessive-compulsive disorder (OCD) is a common inheritable psychiatric disorder characteristic of repetitive thinking, imagination (obsession), and stereotyped behaviors (compulsive). To explore whether there is an alteration of brain functional connectivity (BFC) in patients with OCD during rest, electroencephalogram (EEG) data of healthy controls (HCs) and patients with OCD were collected during rest in both eyes-closed and eyes-open states. Synchronization likelihood and graph theory were applied to construct and analyze brain functional networks of patients with OCD and HCs. Patients with OCD showed abnormal graph-theoretic parameters and impaired small world features in the alpha and beta bands. In addition, the topological analysis consistently showed that the long-range BFC of alpha rhythm was significantly reduced in the bilateral posterior areas in patients with OCD in comparison with HCs, while the BFC in the beta rhythm was significantly increased only in the eyes-open state. The findings suggest that the BFC of patients with OCD show abnormal small-world features and altered topological structure during rest, mainly in alpha and beta bands, which may provide a new insight for the diagnosis and treatment of OCD.

PMID: 30280595 [PubMed - as supplied by publisher]

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