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Combined Isoflurane-Remifentanil Anaesthesia Permits Resting-State fMRI in Children with Severe Epilepsy and Intellectual Disability.

Mon, 07/06/2020 - 23:46

Combined Isoflurane-Remifentanil Anaesthesia Permits Resting-State fMRI in Children with Severe Epilepsy and Intellectual Disability.

Brain Topogr. 2020 Jul 04;:

Authors: Warren AEL, Davidson A, Vogrin SJ, Harvey AS, Bailey C, Dalic LJ, Abbott DF, Archer JS

Abstract
Head motion is a significant barrier to functional MRI (fMRI) in patients who are unable to tolerate awake scanning, including young children or those with cognitive and behavioural impairments. General anaesthesia minimises motion and ensures patient comfort, however the optimal anaesthesia regimen for fMRI in the paediatric setting is unknown. In this study, we tested the feasibility of anaesthetised fMRI in 11 patients (mean age = 9.8 years) with Lennox-Gastaut syndrome, a severe form of childhood-onset epilepsy associated with intellectual disability. fMRI was acquired during clinically-indicated MRI sessions using a synergistic anaesthesia regimen we typically administer for epilepsy neurosurgery: combined low-dose isoflurane (≤ 0.8% end-tidal concentration) with remifentanil (≤ 0.1 mcg/kg/min). Using group-level independent component analysis, we assessed the presence of resting-state networks by spatially comparing results in the anaesthetised patients to resting-state network templates from the 'Generation R' study of 536 similarly-aged non-anaesthetised healthy children (Muetzel et al. in Hum Brain Mapp 37(12):4286-4300, 2016). Numerous resting-state networks commonly studied in non-anaesthetised healthy children were readily identifiable in the anaesthetised patients, including the default-mode, sensorimotor, and frontoparietal networks. Independent component time-courses associated with these networks showed spectral characteristics suggestive of a neuronal origin of fMRI signal fluctuations, including high dynamic range and temporal frequency power predominantly below 0.1 Hz. These results demonstrate the technical feasibility of anaesthetised fMRI in children, suggesting that combined isoflurane-remifentanil anaesthesia may be an effective strategy to extend the emerging clinical applications of resting-state fMRI (for example, neurosurgical planning) to the variety of patient groups who may otherwise be impractical to scan.

PMID: 32623611 [PubMed - as supplied by publisher]

Resting state differences between successful and unsuccessful restrained eaters.

Mon, 07/06/2020 - 23:46

Resting state differences between successful and unsuccessful restrained eaters.

Brain Imaging Behav. 2020 Jul 04;:

Authors: Zhang Y, Wang S, Wei L, Jackson T, Gao X, Xiao M, Gong G, Chen H

Abstract
Restrained eating is a popular weight loss strategy for young women that tends to have limited effectiveness over extended periods of time. Although previous studies have explored and identified possible personality and behavior differences between successful and unsuccessful restrained eaters (REs), there has been a paucity of research on neurophysiological differences.Towards addressing this gap, we assessed brain resting state (Rs) differences in groups of unsuccessful REs (N = 39) and successful REs (N = 31). In line with hypotheses, unsuccessful REs displayed reduced regional homogeneity in brain regions involved in cognitive control (inferior parietal lobe) compared to successful REs. Regions involved in conflict monitoring (anterior cingulate cortex) were also observed to be comparatively less active in the unsuccessful RE group. Finally, based on analyses of independent components and seed-based functional connectivity, regions involved in conflict monitoring and cognitive control, especially those localized within the frontoparietal network, showed weaker connectivities among unsuccessful REs compared to their successful counterparts.These results underscore specific brain Rs differences between successful REs and unsuccessful REs in regions implicated in cognitive control and conflict monitoring.

PMID: 32623562 [PubMed - as supplied by publisher]

R-fMRI reconstruction from k-t undersampled data using a subject-invariant dictionary model and VB-EM with nested minorization.

Mon, 07/06/2020 - 23:46

R-fMRI reconstruction from k-t undersampled data using a subject-invariant dictionary model and VB-EM with nested minorization.

Med Image Anal. 2020 Jun 23;65:101752

Authors: Kulkarni PH, Merchant SN, Awate SP

Abstract
Higher spatial resolution in resting-state functional magnetic resonance imaging (R-fMRI) can give reliable information about the functional networks in the cerebral cortex. Typical methods can achieve higher spatial or temporal resolution by speeding up scans using either (i) complex pulse-sequence designs or (ii) k-space undersampling coupled with priors on the signal. We propose to undersample the R-fMRI acquisition in k-space and time to speedup scans in order to improve spatial resolution. We propose a novel model-based R-fMRI reconstruction framework using a robust, subject-invariant, spatially regularized dictionary prior on the signal. Furthermore, we propose a novel inference framework based on variational Bayesian expectation maximization with nested minorization (VB-EM-NM). Our inference framework allows us to provide an estimate of uncertainty of the reconstruction, unlike typical reconstruction methods. Empirical evaluation of (i) simulated R-fMRI reconstruction and (ii) functional-network estimates from brain R-fMRI reconstructions demonstrate that our framework improves over the state of the art, and, additionally, enables significantly higher spatial resolution.

PMID: 32623273 [PubMed - as supplied by publisher]

Age-related changes in the association of resting-state fMRI signal variability and global functional connectivity in non-demented healthy people.

Sat, 07/04/2020 - 23:39
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Age-related changes in the association of resting-state fMRI signal variability and global functional connectivity in non-demented healthy people.

Psychiatry Res. 2020 Jun 27;291:113257

Authors: Xie W, Peng CK, Shen J, Lin CP, Tsai SJ, Wang S, Chu Q, Yang AC

Abstract
Research suggests that the aging relates to variability of resting-state fMRI (rs-fMRI) signal and the functional connectivity. However, the association between the spatial and temporal activity of resting-state fMRI signal was less documented. We recruited 477 healthy Han Chinese participants, who were separated into young, middle and old groups to investigate the relationship between the variability and global functional connectivity (gFC) in different age ranges using standard deviation (SD) of time series and gFC, respectively. Our analysis revealed the changing patterns during healthy aging: 1) 17 brain regions(Olfactory_L, Orbital_L etc.) were identified to have significant association of age with both SD and gFC respectively by linear regression analysis; 2) Two typical associations could be observed between SD and gFC: positive and negative correlations; 3) The variation ratio of SD to gFC was changing with age at the voxel level by using unsupervised clustering method. It is the first time to combine voxel-wise variability and gFC together for the study of age-related changes with rs-fMRI signal. This study may provide a new clue for understanding the synchronization of human brain based on SD and gFC due to the effect of aging.

PMID: 32619826 [PubMed - as supplied by publisher]

Altered brain language network in idiopathic peripheral facial paralysis patients with dysarthria.

Sat, 07/04/2020 - 23:39
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Altered brain language network in idiopathic peripheral facial paralysis patients with dysarthria.

Ann Transl Med. 2020 Jun;8(11):699

Authors: Gao W, Han X, Li H, Zhu Y, Du L, Wang Y, Shi S, Liu J, Fu C, Zhang L, Ma G

Abstract
Background: Dysarthria is one of the common symptoms of facial paralysis (FP). This study aimed to investigate functional alterations in the brain language network in early idiopathic peripheral FP patients with dysarthria using resting-state functional magnetic resonance imaging (fMRI).
Methods: A total of 45 cases of FP (left 22, right 23) and 34 cases of healthy control (HC) were recruited into this study. The data of patients with left-side FP and matched controls (17 cases) were flipped from left to right, and the brain regions were defined as ipsilateral and contralateral regions. The FC of 16 ROIs in classical language centers and regions that may be involved in language function were calculated. After identifying the differences of FC between the two groups, the correlation analysis between altered FC and TFGS score of oral muscle movement in FP group were analyzed.
Results: The FC between bilateral language regions has a significantly decreased trend in FP group compared with HC group (P<0.05). The ipsilateral inferior frontal gyrus, superior temporal gyrus, and middle temporal gyrus exhibited significantly decreased FC with multiple brain regions. In addition, we found that thalamus and cerebellum also with a significant alteration in FC in FP patients indicating that these two regions may also be involved in the mechanism of dysarthria in FP. The correlation analysis results indicated that the decrease of FC was positively correlated with the severity of oral paralysis.
Conclusions: Idiopathic peripheral FP with dysarthria induces several FC alterations in the brain language network. The severity of oral paralysis is associated with these functional alterations.

PMID: 32617319 [PubMed]

Reproducibility of graph measures at the subject level using resting-state fMRI.

Fri, 07/03/2020 - 23:37
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Reproducibility of graph measures at the subject level using resting-state fMRI.

Brain Behav. 2020 Jul 02;:e01705

Authors: Ran Q, Jamoulle T, Schaeverbeke J, Meersmans K, Vandenberghe R, Dupont P

Abstract
INTRODUCTION: Graph metrics have been proposed as potential biomarkers for diagnosis in clinical work. However, before it can be applied in a clinical setting, their reproducibility should be evaluated.
METHODS: This study systematically investigated the effect of two denoising pipelines and different whole-brain network constructions on reproducibility of subject-specific graph measures. We used the multi-session fMRI dataset from the Brain Genomics Superstruct Project consisting of 69 healthy young adults.
RESULTS: In binary networks, the test-retest variability for global measures was large at low density irrespective of the denoising strategy or the type of correlation. Weighted networks showed very low test-retest values (and thus a good reproducibility) for global graph measures irrespective of the strategy used. Comparing the test-retest values for different strategies, there were significant main effects of the type of correlation (Pearson correlation vs. partial correlation), the (partial) correlation value (absolute vs. positive vs. negative), and weight calculation (based on the raw (partial) correlation values vs. based on transformed Z-values). There was also a significant interaction effect between type of correlation and weight calculation. Similarly as for the binary networks, there was no main effect of the denoising pipeline.
CONCLUSION: Our results demonstrated that normalized global graph measures based on a weighted network using the absolute (partial) correlation as weight were reproducible. The denoising pipeline and the granularity of the whole-brain parcellation used to define the nodes were not critical for the reproducibility of normalized graph measures.

PMID: 32614515 [PubMed - as supplied by publisher]

Theta Burst Transcranial Magnetic Stimulation of Fronto-Parietal Networks: Modulation by Mental State.

Fri, 07/03/2020 - 23:37
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Theta Burst Transcranial Magnetic Stimulation of Fronto-Parietal Networks: Modulation by Mental State.

J Psychiatr Brain Sci. 2020;5:

Authors: Taylor SF, Lee TG, Jonides J, Tso IF, Hernandez-Garcia L

Abstract
Transcranial magnetic stimulation (TMS) treats neuropsychiatric disorders, but effects of stimulation are highly state-dependent and in most therapeutic applications, mental state is not controlled. This exploratory proposal will test the broad hypothesis that when TMS, specifically intermittent theta burst stimulation (iTBS), is applied during a controlled mental state, network changes will be facilitated, compared to stimulation when mental state is uncontrolled. We will focus on the dorsolateral prefrontal cortex (dlPFC) and the associated fronto-parietal network (FPN), which subserves cognitive control, an important neural and behavioral target of therapeutic TMS. After a baseline functional magnetic resonance imaging (fMRI) session, iTBS will be administered to 40 healthy subjects in three sessions over three days in a within-subjects, cross-over design: (1) dlPFC stimulation by iTBS alone, (2) dlPFC stimulation by iTBS while simultaneously performing a cognitive task, and (3) vertex (control) iTBS stimulation. Immediately after each iTBS session, we will measure blood oxygenation level-dependent (BOLD) activation during a cognitive control task ("n-back" task) and during the resting state, using BOLD connectivity and arterial spin labeling (ASL). We will test hypotheses that persisting neural changes and performance enhancement induced by iTBS to the dlPFC, compared to iTBS to the vertex, will affect the FPN, and these effects will be modulated by whether or not subjects receive iTBS when they are engaged in a cognitive control task. Demonstrating this interaction between iTBS and mental state will lay critical groundwork for future studies to show how controlling mental state during TMS can improve therapeutic effects.
Trial Registration: Clinicaltrials.gov NCT04010461.

PMID: 32613082 [PubMed]

Intermittent Theta-Burst Stimulation Over the Suprahyoid Muscles Motor Cortex Facilitates Increased Degree Centrality in Healthy Subjects.

Fri, 07/03/2020 - 23:37
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Intermittent Theta-Burst Stimulation Over the Suprahyoid Muscles Motor Cortex Facilitates Increased Degree Centrality in Healthy Subjects.

Front Hum Neurosci. 2020;14:200

Authors: Zhang G, Gao C, Ruan X, Liu Y, Li Y, Li E, Jiang L, Liu L, Chen X, Jiang X, Xu G, Lan Y, Wei X

Abstract
Theta-burst stimulation (TBS), a variant of repetitive transcranial magnetic stimulation (rTMS), can potentially benefit the treatment of swallowing disorders. However, the after-effects of TBS on the swallowing motor cortex remain uncertain. The newly developed graph-based analysis of the centrality approach has been increasingly used to explore brain networks. The purpose of this study was to identify degree centrality (DC) alterations in the brain network after different TBS protocols were performed over the suprahyoid muscles motor cortex in healthy subjects. A total of 40 right-handed healthy subjects (mean age: 23.73 ± 2.57 years, range: 21-30, 20 females) were included in this study and randomly assigned to two groups, including the continuous TBS (cTBS) group and the intermittent TBS (iTBS) group. All of the subjects underwent resting-state functional magnetic resonance imaging (rs-fMRI) scanning before and after TBS implementation. Compared to the baseline, cTBS resulted in increased DC values in the left inferior frontal gyrus (P < 0.01). In the iTBS group, decreased DC was observed in the left cerebellum and left medial frontal gyrus; However, increased DC was observed in several brain areas including the right superior temporal gyrus, right superior frontal gyrus, right postcentral gyri and left paracentral lobule (P < 0.01). These results indicated that cTBS mainly results in increasing DC in the ipsilateral. However, iTBS is capable of facilitating the excitability of the swallowing motor cortex and increasing the connectivity of multiple brain regions, including the bilateral sensorimotor network, and might have therapeutic potential in the treatment of swallowing disorders.

PMID: 32612517 [PubMed]

Altered Intrinsic Functional Connectivity of the Primary Visual Cortex in Patients with Corneal Ulcer: A Resting-State fMRI Study.

Fri, 07/03/2020 - 23:37
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Altered Intrinsic Functional Connectivity of the Primary Visual Cortex in Patients with Corneal Ulcer: A Resting-State fMRI Study.

Neuropsychiatr Dis Treat. 2020;16:1571-1581

Authors: Hu SL, Tang LY, Fang JW, Su T, Ge QM, Lin Q, Li B, Shi WQ, Li QY, Liang RB, Shao Y

Abstract
Purpose: To investigate differences in the functional connectivity (FC) of the primary visual cortex between patients with corneal ulcer (CU) and healthy controls (HCs) using resting-state functional magnetic resonance imaging.
Patients and Methods: A total of 30 patients with CU and 30 HCs were closely matched in terms of sex, age, and level of education. Two-sample t-test, receiver operating characteristic curve, and Pearson's correlation coefficient analyses were used to determine the differences in FC between the two groups, the mean FC value of patients with CU and HCs, and the correlation between FC signal values and clinical manifestations in different brain regions of patients.
Results: The CU group showed significantly elevated FC in the left and right middle frontal gyri and lower FC with the right cuneus compared with the HC group. In addition, the FC of the right cingulate and left superior frontal gyri also increased in the CU group. The receiver operating characteristic curve revealed high diagnostic value in those brain regions.
Conclusion: CU involves aberrant FC of the primary visual cortex in different brain areas, including visual-related and cognitive-related regions. This finding may unveil the underlying neural mechanisms of impaired visual function in CU.

PMID: 32612359 [PubMed]

No evidence for a relationship between social closeness and similarity in resting-state functional brain connectivity in schoolchildren.

Fri, 07/03/2020 - 23:37
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No evidence for a relationship between social closeness and similarity in resting-state functional brain connectivity in schoolchildren.

Sci Rep. 2020 Jul 01;10(1):10710

Authors: McNabb CB, Burgess LG, Fancourt A, Mulligan N, FitzGibbon L, Riddell P, Murayama K

Abstract
Previous research suggests that the proximity of individuals in a social network predicts how similarly their brains respond to naturalistic stimuli. However, the relationship between social connectedness and brain connectivity in the absence of external stimuli has not been examined. To investigate whether neural homophily between friends exists at rest we collected resting-state functional magnetic resonance imaging (fMRI) data from 68 school-aged girls, along with social network information from all pupils in their year groups (total 5,066 social dyads). Participants were asked to rate the amount of time they voluntarily spent with each person in their year group, and directed social network matrices and community structure were then determined from these data. No statistically significant relationships between social distance, community homogeneity and similarity of global-level resting-state connectivity were observed. Nor were we able to predict social distance using a regularised regression technique (i.e. elastic net regression based on the local-level similarities in resting-state whole-brain connectivity between participants). Although neural homophily between friends exists when viewing naturalistic stimuli, this finding did not extend to functional connectivity at rest in our population. Instead, resting-state connectivity may be less susceptible to the influences of a person's social environment.

PMID: 32612156 [PubMed - in process]

An open database of resting-state fMRI in awake rats.

Thu, 07/02/2020 - 23:35
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An open database of resting-state fMRI in awake rats.

Neuroimage. 2020 Jun 28;:117094

Authors: Liu Y, Perez PD, Ma Z, Ma Z, Dopfel D, Cramer S, Tu W, Zhang N

Abstract
Rodent models are essential to translational research in health and disease. Investigation in rodent brain function and organization at the systems level using resting-state functional magnetic resonance imaging (rsfMRI) has become increasingly popular. Due to this rapid progress, publicly shared rodent rsfMRI databases can be of particular interest and importance to the scientific community, as inspired by human neuroscience and psychiatric research that are substantially facilitated by open human neuroimaging datasets. However, such databases in rats are still rare. In this paper, we share an open rsfMRI database acquired in 90 rats with a well-established awake imaging paradigm that avoids anesthesia interference. Both raw and preprocessed data are made publicly available. Procedures in data preprocessing to remove artefacts induced by the scanner, head motion, non-neural physiological noise are described in details. We also showcase inter-regional functional connectivity and functional networks obtained from the database.

PMID: 32610063 [PubMed - as supplied by publisher]

Brain functional network alterations caused by a strong desire to void in healthy adults: a graph theory analysis study.

Thu, 07/02/2020 - 23:35
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Brain functional network alterations caused by a strong desire to void in healthy adults: a graph theory analysis study.

Neurourol Urodyn. 2020 Jul 01;:

Authors: Pang D, Gao Y, Liao L, Ying X

Abstract
PURPOSE: This resting-state functional magnetic resonance imaging (fMRI) study determined the functional connectivity (FC) changes and topologic property alterations of the brain functional network provoked by a strong desire to void in healthy adults using a graph theory analysis (GTA).
MATERIALS AND METHODS: Thirty-four healthy, right-handed subjects filled their bladders by drinking water. The subjects were scanned under an empty bladder and a strong desire to void states. The Pearson's correlation coefficients were calculated among 90 brain regions in the automated anatomical labeling (AAL) atlas to construct the brain functional network. A paired t test (P < .05, after false discovery rate [FDR] correction) was used to detect significant differences in the FC, topologic properties (small-world parameters [gamma, sigma], Cp , Lp , Eglob , Eloc , and Enodal ) between the two states in all subjects.
RESULTS: Both the two states showed small-world network properties. The clustering coefficient (Cp ) and local efficiency (Eloc ) in the whole brain network decreased, while the FC within the default mode network (DMN) increased during the strong desire to void compared with the empty bladder state. Moreover, an increased nodal efficiency (Enodal ) was detected in the basal ganglia (BG), DMN, sensorimotor-related network (SMN), and visual network (VN).
CONCLUSION: We detected FC changes and topologic property alterations in brain functional networks caused by a strong desire to void in healthy and suggest that the micturition control may be a process dominated by DMN and coordinated by multiple sub-networks (such as, BG, SMN, and VN), which could serve as a baseline for understanding the pathologic process underlying bladder dysfunction and be useful to improve targeted therapy in the future.

PMID: 32609930 [PubMed - as supplied by publisher]

Aberrant Executive Control and Auditory Networks in Recent-Onset Schizophrenia.

Thu, 07/02/2020 - 23:35
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Aberrant Executive Control and Auditory Networks in Recent-Onset Schizophrenia.

Neuropsychiatr Dis Treat. 2020;16:1561-1570

Authors: Joo SW, Yoon W, Jo YT, Kim H, Kim Y, Lee J

Abstract
Purpose: Despite a large number of resting-state functional MRI (rsfMRI) studies in schizophrenia, current evidence on the abnormalities of functional connectivity (FC) of resting-state networks shows high variability, and the findings on recent-onset schizophrenia are insufficient compared to those on chronic schizophrenia.
Patients and Methods: We performed a rsfMRI in 46 patients with recent-onset schizophrenia and 22 healthy controls. Group independent component brainmap and dual regression were performed for voxel-wise comparisons between the groups. Correlation of the symptom severity, cognitive function, duration of illness, and a total antipsychotics dose with FC was evaluated with Spearman's rho correlation.
Results: The patient group had areas with a significantly decreased FC compared to that of the control group in which it existed in the left supplementary motor cortex and supramarginal gyrus (the executive control network) and the right postcentral gyrus (the auditory network). The patient group had a significant correlation of the total antipsychotics dose with the FC of the cluster in the left supplementary motor cortex in the executive control network.
Conclusion: Patients with recent-onset schizophrenia have decreased FC of the executive control and auditory networks compared to healthy controls.

PMID: 32606708 [PubMed]

Brain and behaviour in post-acute stroke: Reduction in seeking and posterior cingulate neuronal variability.

Thu, 07/02/2020 - 23:35
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Brain and behaviour in post-acute stroke: Reduction in seeking and posterior cingulate neuronal variability.

J Clin Exp Neuropsychol. 2020 Jul 01;:1-18

Authors: Farinelli M, Cevolani D, Gestieri L, Romaniello C, Maffei M, Agati R, Leo MR, Huang Z, Pedone V, Northoff G

Abstract
INTRODUCTION: Stroke is a complex event on both behavioral and neuronal grounds. Recent investigations evidence the central role of subcortical damage on the post-stroke brain and behavior reorganization. We have conducted an exploratory study combining anatomical lesion analysis, functional analysis of resting state fMRI, and behavioral assessment with focus on exploration as represented by SEEKING.
METHOD: 24 stroke inpatients were studied immediately after their clinical stabilization post-stroke; neuronal variability in fMRI along with behavioral outcomes were assessed. These outcomes were compared with a control group of 22 healthy subjects.
RESULTS: First, we observed predominant subcortical lesions in our sample with all stroke patients showing subcortical lesions and only some exhibiting additional cortical lesions. Second, we observed significantly reduced neuronal variability in the posterior cingulate cortex (PCC) that did not show any structural damage. Third, our stroke subjects showed reduced SEEKING which was related to reduced PCC neuronal variability in an abnormal way (compared to healthy subjects). This last outcome was assessed by considering the subset of 11 stroke subjects for which fMRI and behavioral outcomes were jointly measured.
CONCLUSIONS: Taken together, our findings suggest that damage in subcortical regions may play a central role in abnormalities in both cortical activity (PCC) and associated behavior of post-stroke reorganization. Accounting for these aspects may have significant implications to optimize multidisciplinary rehabilitation processes, particularly during the early steps of recovery, reducing the impact of stroke on the patient and caregiver quality of life.

PMID: 32605471 [PubMed - as supplied by publisher]

Structural-functional decoupling predicts suicide attempts in bipolar disorder patients with a current major depressive episode.

Wed, 07/01/2020 - 23:32
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Structural-functional decoupling predicts suicide attempts in bipolar disorder patients with a current major depressive episode.

Neuropsychopharmacology. 2020 Jun 30;:

Authors: Jiang H, Zhu R, Tian S, Wang H, Chen Z, Wang X, Shao J, Qin J, Shi J, Liu H, Chen Y, Yao Z, Lu Q

Abstract
Bipolar disorder (BD) is associated with a high risk of suicidality, and it is challenging to predict suicide attempts in clinical practice to date. Although structural and functional connectivity alterations from neuroimaging studies have been previously reported in BD with suicide attempts, little is known about how abnormal structural and functional connectivity relates to each other. Here, we hypothesize that structure connectivity constrains functional connectivity, and structural-functional coupling is a more sensitive biomarker to detect subtle brain abnormalities than any single modality in BD patients with a current major depressive episode who had attempted suicide. By investigating structural and resting-state fMRI connectivity, as well as their coupling among 191 BD depression patients with or without a history of suicide attempts and 113 healthy controls, we found that suicide attempters in BD depression patients showed significantly decreased central-temporal structural connectivity, increased frontal-temporal functional connectivity, along with decreased structural-functional coupling compared with non-suicide attempters. Crucially, the altered structural connectivity network predicted the abnormal functional connectivity network profile, and the structural-functional coupling was significantly correlated with suicide risk but not with depression or anxiety severity. Our findings suggest that the structural connectome is the key determinant of brain dysfunction, and structural-functional coupling could serve as a valuable trait-like biomarker for BD suicidal predication over and above the intramodality network connectivity. Such a measure can have clinical implications for early identification of suicide attempters with BD depression and inform strategies for prevention.

PMID: 32604403 [PubMed - as supplied by publisher]

Estimation and Validation of Individualized Dynamic Brain Models with Resting State fMRI.

Wed, 07/01/2020 - 23:32
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Estimation and Validation of Individualized Dynamic Brain Models with Resting State fMRI.

Neuroimage. 2020 Jun 27;:117046

Authors: Singh MF, Braver TS, Cole MW, Ching S

Abstract
A key challenge for neuroscience is to develop generative, causal models of the human nervous system in an individualized, data-driven manner. Previous initiatives have either constructed biologically-plausible models that are not constrained by individual-level human brain activity or used data-driven statistical characterizations of individuals that are not mechanistic. We aim to bridge this gap through the development of a new modeling approach termed Mesoscale Individualized Neurodynamic (MINDy) modeling, wherein we fit nonlinear dynamical systems models directly to human brain imaging data. The MINDy framework is able to produce these data-driven network models for hundreds to thousands of interacting brain regions in just 1-3 minutes per subject. We demonstrate that the models are valid, reliable, and robust. We show that MINDy models are predictive of individualized patterns of resting-state brain dynamical activity. Furthermore, MINDy is better able to uncover the mechanisms underlying individual differences in resting state activity than functional connectivity methods.

PMID: 32603858 [PubMed - as supplied by publisher]

T-Distribution Stochastic Neighbor Embedding for Fine Brain Functional Parcellation on rs-fMRI.

Wed, 07/01/2020 - 23:32
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T-Distribution Stochastic Neighbor Embedding for Fine Brain Functional Parcellation on rs-fMRI.

Brain Res Bull. 2020 Jun 27;:

Authors: Hu Y, Li X, Wang L, Han B, Nie S

Abstract
In human functional connectome and network analyses, brain subregions that are functionally parcellated have a better consistency than do anatomical subregions. Resting-state functional magnetic resonance imaging (rs-fMRI) signals can function as coherent connectivity patterns that can be used to assess human brain functional architecture. In this paper, an optimized framework that combines automatic spectral clustering with dimensionality reduction is presented for fine-grained functional parcellation of rs-fMRI of the human brain. First, the t-distribution stochastic neighborhood embedding (t-SNE) algorithm extracts features from the high-dimensional functional connectivity patterns between voxels of the brain regions to be segmented and the whole brain. Then, the number of clusters is determined, and each voxel in the regions is parcellated by the automatic spectral clustering algorithm based on the eigengap. A quantitative validation of the proposed methodology in synthetic seed regions demonstrated its accuracy and performance superiority compared to previous methods. Moreover, we were able to successfully divide the parahippocampal gyrus into three subregions in both the left and right hemispheres. The distinctive functional connectivity patterns of these subregions, educed from rs-fMRI data, further established the validity of the parcellation results. Notably, our findings reveal a novel insight into brain functional parcellation as well as the construction of functional atlases for future Cognitive Connectome analyses.

PMID: 32603775 [PubMed - as supplied by publisher]

Immediate Abnormal Intrinsic Brain Activity Patterns in Patients with End-stage Renal Disease During a Single Dialysis Session : Resting-state Functional MRI Study.

Wed, 07/01/2020 - 23:32
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Immediate Abnormal Intrinsic Brain Activity Patterns in Patients with End-stage Renal Disease During a Single Dialysis Session : Resting-state Functional MRI Study.

Clin Neuroradiol. 2020 Jun 29;:

Authors: Peng C, Yang H, Ran Q, Zhang L, Liu C, Fang Y, Liu Y, Cao Y, Liang R, Ren H, Hu Q, Mei X, Jiang Y, Luo T

Abstract
PURPOSE: To investigate cerebral amplitude of low-frequency fluctuations (ALFF) changes during a single hemodialysis (HD) in end-stage renal disease (ESRD) patients who need maintenance HD.
MATERIALS AND METHODS: A total of 24 patients and 27 healthy subjects were included. The patients underwent neuropsychological tests and took twice resting-state fMRI (rs-fMRI) (before and after HD). Healthy group had one rs-fMRI. The zALFF based on rs-fMRI was calculated. Paired t and independent t test was applied to compare zALFF among groups. The associations between zALFF and duration of HD, ultrafiltration volume, and neuropsychological tests was calculated by partial correlation.
RESULTS: Compared to healthy group, patients before HD showed significant worse performances on digit symbol test (DST) and serial dotting test (SDT). Patients after HD performed DST better than before HD. The patients after HD showed higher zALFF in left putamen than before HD. Multiple regions of both HD groups showed significant lower zALFF than healthy group. The zALFF of left putamen of patients after HD was significant negative correlated with the ultrafiltration volume (R = -0.679). The zALFF in patients before HD exhibited significantly positive or negative correlations with DST and SDT in multiple regions. The zALFF of patients after HD significantly negative correlated with DST in right temporal, positive and negative correlated with ultrafiltration volume in right frontal, left putamen respectively.
CONCLUSION: ESRD patients showed changed spontaneous brain activity and cognitive impairments. After a single HD session, patients performed better in neuropsychological test, and spontaneous brain activity changed in left putamen. Ultrafiltration volume might be associated with activity of left putamen.

PMID: 32601841 [PubMed - as supplied by publisher]

Bring the Noise: Reconceptualizing Spontaneous Neural Activity.

Wed, 07/01/2020 - 23:32
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Bring the Noise: Reconceptualizing Spontaneous Neural Activity.

Trends Cogn Sci. 2020 Jun 26;:

Authors: Uddin LQ

Abstract
Definitions of what constitutes the 'signal of interest' in neuroscience can be controversial, due in part to continuously evolving notions regarding the significance of spontaneous neural activity. This review highlights how the challenge of separating brain signal from noise has led to new conceptualizations of brain functional organization at both the micro- and macroscopic level. Recent debates in the functional neuroimaging community surrounding artifact removal processes have revived earlier discussions surrounding how to appropriately isolate and measure neuronal signals against a background of noise from various sources. Insights from electrophysiological studies and computational modeling can inform current theory and data analytic practices in human functional neuroimaging, given that signal and noise may be inextricably linked in the brain.

PMID: 32600967 [PubMed - as supplied by publisher]

Identifying psychosis spectrum youth using support vector machines and cerebral blood perfusion as measured by arterial spin labeled fMRI.

Wed, 07/01/2020 - 23:32
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Identifying psychosis spectrum youth using support vector machines and cerebral blood perfusion as measured by arterial spin labeled fMRI.

Neuroimage Clin. 2020 Jun 04;27:102304

Authors: Overton DJ, Bhagwat N, Viviano JD, Jacobs GR, Voineskos AN

Abstract
Altered cerebral blood flow (CBF), as measured by arterial spin labelling (ASL), has been observed in several psychiatric conditions, but is a generally underutilized MRI technique, especially in the study of psychosis spectrum (PS) symptoms. We aimed to determine group differences in ASL resting state functional connectivity (rsFC) between PS and non-PS youth, and the reliability of a support vector machine (SVM) classifier trained on ASL rsFC features to differentiate PS and non-PS youth, especially compared to blood oxygen level dependent (BOLD) fMRI. 1146 youth aged 8-22 with ASL and BOLD data from the Philadelphia Neurodevelopmental Cohort were analyzed. Widespread ASL hyperconnectivity was found in the left cuneus, precuneus, and dorsolateral prefrontal cortex, and hypoconnectivity was found in the left cingulate cortex and orbitofrontal area (multiple linear regression, FDR corrected). An SVM trained on ASL and BOLD features outperformed either modality alone (AUCBOTH = 0.72 versus AUCASL = 0.68 and AUCBOLD = 0.67). Classification performance and precision improved when the non-PS group had no psychiatric comorbidities. The relative success of the classifier suggests ASL rsFC changes exist in PS individuals that differ from BOLD rsFC changes, and extends previous findings of CBF dysregulation in PS.

PMID: 32599552 [PubMed - as supplied by publisher]