New resting-state fMRI related studies at PubMed

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Oxytocin modulates intrinsic neural activity in patients with chronic low back pain.

Sun, 02/16/2020 - 16:00
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Oxytocin modulates intrinsic neural activity in patients with chronic low back pain.

Eur J Pain. 2020 Feb 15;:

Authors: Schneider I, Schmitgen MM, Boll S, Roth C, Nees F, Usai K, Herpertz SC, Wolf RC

Abstract
BACKGROUND: Modulation of pain perception by oxytocin (OXT) has attracted increased scientific and clinical interest. Neural mechanisms underlying these effects are poorly understood. In this study, we aimed to investigate the effects of intranasally applied OXT on intrinsic neural activity in patients with chronic low back pain (cLBP).
METHODS: Twenty-four male patients with cLBP and 23 healthy males were examined using resting-state functional magnetic resonance imaging. Participants were scanned twice and received either intranasally applied OXT (24 international units) or placebo 40 minutes before scanning. The fractional amplitude of low-frequency fluctuations (fALFF) was computed to investigate regionally specific effects of OXT on intrinsic neural activity. In addition a multivariate statistical data analysis strategy was employed to explore OXT-effects on functional network strength.
RESULTS: Differential effects of OXT were observed in cLBP and healthy controls. FALFF decreased in left nucleus accumbens and right thalamus in cLBP and increased in right thalamus in healthy controls after OXT application compared to placebo. OXT also induced activity changes in bilateral thalamus, left caudate nucleus, and right amygdala in cLBP. OXT was associated with increased medial frontal, parietal and occipital functional network strength, though this effect was not group-specific. Regression analyses revealed significant associations between left nucleus accumbens, left caudate nucleus, and right amygdala with pain-specific psychometric scores in cLBP.
CONCLUSIONS: These data suggest OXT-related modulation of regional activity and neural network strength in patients with cLBP and healthy controls. In patients, distinct regions of the pain matrix may be responsive to modulation by OXT.

PMID: 32061140 [PubMed - as supplied by publisher]

The Neural Dynamics of Individual Differences in Episodic Autobiographical Memory.

Sun, 02/16/2020 - 16:00
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The Neural Dynamics of Individual Differences in Episodic Autobiographical Memory.

eNeuro. 2020 Feb 10;:

Authors: Petrican R, Palombo DJ, Sheldon S, Levine B

Abstract
The ability to mentally travel to specific events from one's past, dubbed episodic autobiographical memory (E-AM), contributes to adaptive functioning. Nonetheless, the mechanisms underlying its typical interindividual variation remain poorly understood. To address this issue, we capitalize on existing evidence that successful performance on E-AM tasks draws on the ability to visualize past episodes and reinstate their unique spatiotemporal context. Hence, here, we test whether features of the brain's functional architecture relevant to perceptual versus conceptual processes shape individual differences in both self-rated E-AM and laboratory-based episodic memory for random visual scene sequences (visual EM). We propose that superior subjective E-AM and visual EM are associated with greater similarity in static neural organization patterns, potentially indicating greater efficiency in switching, between rest and mental states relevant to encoding perceptual information. Complementarily, we postulate that impoverished subjective E-AM and visual EM are linked to dynamic brain organization patterns implying a predisposition towards semanticizing novel perceptual information. Analyses were conducted on resting state and task-based fMRI data from 329 participants (160 women) in the Human Connectome Project who completed visual and verbal EM assessments, and an independent gender diverse sample (N = 59) who self-rated their E-AM. Interindividual differences in subjective E-AM were linked to the same neural mechanisms underlying visual, but not verbal, EM, in general agreement with the hypothesized static and dynamic brain organization patterns. Our results suggest that higher E-AM entails more efficient processing of temporally extended information sequences, whereas lower E-AM entails more efficient semantic or gist-based processing.Significance Statement The ability to revisit specific events from one's past is key to identity formation and optimal interpersonal functioning. Nonetheless, the mechanisms underlying its typical interindividual variation are yet to be fully characterized. Here, we provide novel evidence that, among younger adults, dispositional variations in subjective mental time travel draw on the same dynamic and static features of the brain's architecture that are uniquely implicated in memory for spatiotemporal contexts. Specifically, the subjective sense of being able to revisit one's past relates to neural mechanisms supporting serial mental operations, whereas difficulties in accessing past experiences may be traced back to a predisposition towards gist-based processing of incoming information.

PMID: 32060035 [PubMed - as supplied by publisher]

Frequency-Specific Changes of Resting Brain Activity in Parkinson's Disease: A Machine Learning Approach.

Sun, 02/16/2020 - 16:00
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Frequency-Specific Changes of Resting Brain Activity in Parkinson's Disease: A Machine Learning Approach.

Neuroscience. 2020 Feb 11;:

Authors: Tian ZY, Qian L, Fang L, Peng XH, Zhu XH, Wu M, Wang WZ, Zhang WH, Zhu BQ, Wan M, Hu X, Shao J

Abstract
The application of Resting State functional MRI (RS-fMRI) in Parkinson's disease was widely performed using standard statistical tests, however, the machine learning approach has not yet been investigated in PD using RS-fMRI. In current study, we utilized the mean regional amplitude values as the features in patients with PD (n = 72) and in healthy controls (HC, n = 89). The t-test and linear support vector machine were employed to select the features and make prediction, respectively. Three frequency bins (Slow-5: 0.0107 - 0.0286 Hz; Slow-4: 0.0286 - 0.0821 Hz; Conventional: 0.01 - 0.08 Hz) were analyzed. Our results showed that the Slow-4 may provide important information than Slow-5 in PD, and it had almost identical classification performance compared with the Combined (Slow-5 and Slow-4) and Conventional frequency bands. Similar with previous neuroimaging studies in PD, the discriminative regions were mainly included the disrupted motor system, aberrant visual cortex, dysfunction of paralimbic/limbic and basal ganglia networks. The lateral parietal lobe, such as right IPL and SMG, was detected as the discriminative features exclusively in Slow-4. Our findings, at the first time, indicated that the machine learning approach is a promising choice for detecting abnormal regions in PD, and a multi-frequency scheme would provide us more specific information.

PMID: 32059985 [PubMed - as supplied by publisher]

Toward identifying reproducible brain signatures of obsessive-compulsive profiles: rationale and methods for a new global initiative.

Sun, 02/16/2020 - 16:00
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Toward identifying reproducible brain signatures of obsessive-compulsive profiles: rationale and methods for a new global initiative.

BMC Psychiatry. 2020 Feb 14;20(1):68

Authors: Simpson HB, van den Heuvel OA, Miguel EC, Reddy YCJ, Stein DJ, Lewis-Fernández R, Shavitt RG, Lochner C, Pouwels PJW, Narayanawamy JC, Venkatasubramanian G, Hezel DM, Vriend C, Batistuzzo MC, Hoexter MQ, de Joode NT, Costa DL, de Mathis MA, Sheshachala K, Narayan M, van Balkom AJLM, Batelaan NM, Venkataram S, Cherian A, Marincowitz C, Pannekoek N, Stovezky YR, Mare K, Liu F, Otaduy MCG, Pastorello B, Rao R, Katechis M, Van Meter P, Wall M

Abstract
BACKGROUND: Obsessive-compulsive disorder (OCD) has a lifetime prevalence of 2-3% and is a leading cause of global disability. Brain circuit abnormalities in individuals with OCD have been identified, but important knowledge gaps remain. The goal of the new global initiative described in this paper is to identify robust and reproducible brain signatures of measurable behaviors and clinical symptoms that are common in individuals with OCD. A global approach was chosen to accelerate discovery, to increase rigor and transparency, and to ensure generalizability of results.
METHODS: We will study 250 medication-free adults with OCD, 100 unaffected adult siblings of individuals with OCD, and 250 healthy control subjects at five expert research sites across five countries (Brazil, India, Netherlands, South Africa, and the U.S.). All participants will receive clinical evaluation, neurocognitive assessment, and magnetic resonance imaging (MRI). The imaging will examine multiple brain circuits hypothesized to underlie OCD behaviors, focusing on morphometry (T1-weighted MRI), structural connectivity (Diffusion Tensor Imaging), and functional connectivity (resting-state fMRI). In addition to analyzing each imaging modality separately, we will also use multi-modal fusion with machine learning statistical methods in an attempt to derive imaging signatures that distinguish individuals with OCD from unaffected siblings and healthy controls (Aim #1). Then we will examine how these imaging signatures link to behavioral performance on neurocognitive tasks that probe these same circuits as well as to clinical profiles (Aim #2). Finally, we will explore how specific environmental features (childhood trauma, socioeconomic status, and religiosity) moderate these brain-behavior associations.
DISCUSSION: Using harmonized methods for data collection and analysis, we will conduct the largest neurocognitive and multimodal-imaging study in medication-free subjects with OCD to date. By recruiting a large, ethno-culturally diverse sample, we will test whether there are robust biosignatures of core OCD features that transcend countries and cultures. If so, future studies can use these brain signatures to reveal trans-diagnostic disease dimensions, chart when these signatures arise during development, and identify treatments that target these circuit abnormalities directly. The long-term goal of this research is to change not only how we conceptualize OCD but also how we diagnose and treat it.

PMID: 32059696 [PubMed - in process]

Multi-modal normalization of resting-state using local physiology reduces changes in functional connectivity patterns observed in mTBI patients.

Sat, 02/15/2020 - 15:20
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Multi-modal normalization of resting-state using local physiology reduces changes in functional connectivity patterns observed in mTBI patients.

Neuroimage Clin. 2020 Feb 04;26:102204

Authors: Champagne AA, Coverdale NS, Ross A, Chen Y, Murray CI, Dubowitz D, Cook DJ

Abstract
Blood oxygenation level dependent (BOLD) resting-state functional magnetic resonance imaging (rs-fMRI) may serve as a sensitive marker to identify possible changes in the architecture of large-scale networks following mild traumatic brain injury (mTBI). Differences in functional connectivity (FC) measurements derived from BOLD rs-fMRI may however be confounded by changes in local cerebrovascular physiology and neurovascular coupling mechanisms, without changes in the underlying neuronally driven connectivity of networks. In this study, multi-modal neuroimaging data including BOLD rs-fMRI, baseline cerebral blood flow (CBF0) and cerebrovascular reactivity (CVR; acquired using a hypercapnic gas breathing challenge) were collected in 23 subjects with reported mTBI (14.6±14.9 months post-injury) and 27 age-matched healthy controls. Despite no group differences in CVR within the networks of interest (P > 0.05, corrected), significantly higher CBF0 was documented in the mTBI subjects (P < 0.05, corrected), relative to the controls. A normalization method designed to account for differences in CBF0 post-mTBI was introduced to evaluate the effects of such an approach on reported group differences in network connectivity. Inclusion of regional perfusion measurements in the computation of correlation coefficients within and across large-scale networks narrowed the differences in FC between the groups, suggesting that this approach may elucidate unique changes in connectivity post-mTBI while accounting for shared variance with CBF0. Altogether, our results provide a strong paradigm supporting the need to account for changes in physiological modulators of BOLD in order to expand our understanding of the effects of brain injury on large-scale FC of cortical networks.

PMID: 32058317 [PubMed - as supplied by publisher]

Altered topological organization of functional brain networks in drug-naive patients with paroxysmal kinesigenic dyskinesia.

Sat, 02/15/2020 - 15:20
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Altered topological organization of functional brain networks in drug-naive patients with paroxysmal kinesigenic dyskinesia.

J Neurol Sci. 2020 Jan 22;411:116702

Authors: Zhang Y, Ren J, Qin Y, Yang C, Zhang T, Gong Q, Yang T, Zhou D

Abstract
BACKGROUND: Previous neuroimaging studies have revealed aberrant basal ganglia-thalamocortical circuit in patients with paroxysmal kinesigenic dyskinesia (PKD) with drug treatment. This study aims to investigate the topological organization of functional networks in drug-naive PKD.
METHODS: Resting-state functional magnetic resonance imaging (rs-fMRI) was performed in 24 drug-naive PKD patients and 24 age, gender and mean framewise displacement (FD)-matched healthy controls (HCs). The network topological properties (including global and nodal measures) were analyzed between two groups by using graph-based theoretical approaches. Pearson's correlation analysis was performed between significant metrics and duration of disease and the age of onset of patients with PKD.
RESULTS: Compare to HCs, the drug-naïve PKD patients showed increased nodal centralities mainly in left precentral gyrus, basal ganglia and limbic regions and decreased nodal centralities in the temporal pole. Our results showed that drug-naïve PKD patients presented the small-world topology and at the global level no significant differences were found between PKD and HCs. In the correlation analysis, the increased nodal efficiency in the left pallidum was positively correlated with the onset of age.
CONCLUSIONS: Our findings supported the previous observation of the disruptive cortical-basal ganglia circuitry in PKD patients, but difference in that the prominent change of precentral area and temporal pole were also observed in our study when the potential impact of drug was excluded. These findings may provide a novel insight into further delineation of the pathophysiological genesis and possible target for PKD.

PMID: 32058179 [PubMed - as supplied by publisher]

Mind-wandering in Parkinson's disease hallucinations reflects primary visual and default network coupling.

Sat, 02/15/2020 - 15:20
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Mind-wandering in Parkinson's disease hallucinations reflects primary visual and default network coupling.

Cortex. 2020 Jan 22;125:233-245

Authors: Walpola IC, Muller AJ, Hall JM, Andrews-Hanna JR, Irish M, Lewis SJG, Shine JM, O'Callaghan C

Abstract
Visual hallucinations are an underappreciated symptom affecting the majority of patients during the natural history of Parkinson's disease. Little is known about other forms of abstract and internally generated cognition - such as mind-wandering - in this population, but emerging evidence suggests that an interplay between the brain's primary visual and default networks might play a crucial role in both internally generated imagery and hallucinations. Here, we explored the association between mind-wandering and visual hallucinations in Parkinson's disease, and their relationship with brain network coupling. We administered a validated thought-sampling task to 38 Parkinson's disease patients (18 with hallucinations; 20 without) and 40 controls, to test the hypothesis that individuals with hallucinations experience an increased frequency of mind-wandering. Group differences in the association between mind-wandering frequency and brain network coupling were also examined using resting state functional magnetic resonance imaging. Our results showed that patients with hallucinations exhibited significantly higher mind-wandering frequencies compared to non-hallucinators, who in turn had reduced levels of mind-wandering relative to controls. At the level of brain networks, inter-network connectivity and seed-to-voxel analyses identified that increased mind-wandering in the hallucinating versus non-hallucinating group was associated with greater coupling between the primary visual cortex and dorsal default network. Taken together, our results suggest a relative preservation of mind-wandering in Parkinson's disease patients who experience visual hallucinations, which is associated with increased visual cortex-default network coupling. We propose that the preservation of florid abstract and internally generated cognition in the context of the Parkinson's disease can contribute to visual hallucinations, whereas healthy individuals experience only the vivid images of the mind's eye. These findings refine current models of visual hallucinations by identifying a specific cognitive phenomenon and neural substrate consistent with the top-down influences over perception that have been implicated in hallucinations across neuropsychiatric disorders.

PMID: 32058090 [PubMed - as supplied by publisher]

Multi-subject Stochastic Blockmodels for adaptive analysis of individual differences in human brain network cluster structure.

Sat, 02/15/2020 - 15:20
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Multi-subject Stochastic Blockmodels for adaptive analysis of individual differences in human brain network cluster structure.

Neuroimage. 2020 Feb 10;:116611

Authors: Pavlović DM, Guillaume BRL, Towlson EK, Kuek NMY, Afyouni S, Vértes PE, Thomas Yeo BT, Bullmore ET, Nichols TE

Abstract
There is great interest in elucidating the cluster structure of brain networks in terms of modules, blocks or clusters of similar nodes. However, it is currently challenging to handle data on multiple subjects since most of the existing methods are applicable only on a subject-by-subject basis or for analysis of an average group network. The main limitation of per-subject models is that there is no obvious way to combine the results for group comparisons, and of group-averaged models that they do not reflect the variability between subjects. Here, we propose two new extensions of the classical Stochastic Blockmodel (SBM) that use a mixture model to estimate blocks or clusters of connected nodes, combined with a regression model to capture the effects on cluster structure of individual differences on subject-level covariates. Multi-subject Stochastic Blockmodels (MS-SBM) can flexibly account for between-subject variability in terms of a homogenous or heterogeneous effect on connectivity of covariates such as age or diagnostic status. Using synthetic data, representing a range of block sizes and cluster structures, we investigate the accuracy of the estimated MS-SBM parameters as well as the validity of inference procedures based on Wald, likelihood ratio and Monte Carlo permutation tests. We show that multi-subject SBMs recover the true cluster structure of synthetic networks more accurately and adaptively than standard methods for modular decomposition. Permutation tests of MS-SBM parameters were more robustly valid for statistical inference and Type I error control than tests based on standard asymptotic assumptions. Applied to analysis of multi-subject resting-state fMRI networks (13 healthy volunteers; 12 people with schizophrenia; N=268 brain regions), we show that the Heterogeneous Stochastic Blockmodel identifies a range of network topologies simultaneously, including modular and core-periphery structure.

PMID: 32058004 [PubMed - as supplied by publisher]

TbCAPs: A ToolBox for Co-Activation pattern analysis.

Sat, 02/15/2020 - 15:20
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TbCAPs: A ToolBox for Co-Activation pattern analysis.

Neuroimage. 2020 Feb 10;:116621

Authors: Bolton TAW, Tuleasca C, Wotruba D, Rey G, Dhanis H, Gauthier B, Delavari F, Morgenroth E, Gaviria J, Blondiaux E, Smigielski L, Van De Ville D

Abstract
Functional magnetic resonance imaging provides rich spatio-temporal data of human brain activity during task and rest. Many recent efforts have focussed on characterising dynamics of brain activity. One notable instance is co-activation pattern (CAP) analysis, a frame-wise analytical approach that disentangles the different functional brain networks interacting with a user-defined seed region. While promising applications in various clinical settings have been demonstrated, there is not yet any centralised, publicly accessible resource to facilitate the deployment of the technique. Here, we release a working version of TbCAPs, a new toolbox for CAP analysis, which includes all steps of the analytical pipeline, introduces new methodological developments that build on already existing concepts, and enables a facilitated inspection of CAPs and resulting metrics of brain dynamics.The toolbox is available on a public academic repository at https://c4science.ch/source/CAP_Toolbox.git. In addition, to illustrate the feasibility and usefulness of our pipeline, we describe an application to the study of human cognition. CAPs are constructed from resting-state fMRI using as seed the right dorsolateral prefrontal cortex, and, in a separate sample, we successfully predict a behavioural measure of continuous attentional performance from the metrics of CAP dynamics (R = 0.59).

PMID: 32058000 [PubMed - as supplied by publisher]

Brain network interactions in transgender individuals with gender incongruence.

Sat, 02/15/2020 - 15:20
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Brain network interactions in transgender individuals with gender incongruence.

Neuroimage. 2020 Feb 10;:116613

Authors: Uribe C, Junque C, Gómez-Gil E, Abos A, Mueller SC, Guillamon A

Abstract
Functional brain organization in transgender persons remains unclear. Our aims were to investigate global and regional connectivity differences within functional networks in transwomen and transmen with early-in-life onset gender incongruence; and to test the consistency of two available hypotheses that attempted to explain gender variants: (i) a neurodevelopmental cortical hypothesis that suggests the existence of different brain phenotypes based on structural MRI data and genes polymorphisms of sex hormone receptors; (ii) a functional-based hypothesis in relation to regions involved in the own body perception. T2*-weighted images in a 3-T MRI were obtained from 29 transmen and 17 transwomen as well as 22 cisgender women and 19 cisgender men. Resting-state independent component analysis, seed-to-seed functional network and graph theory analyses were performed. Transmen, transwomen, and cisgender women had decreased connectivity compared with cisgender men in superior parietal regions, as part of the salience (SN) and the executive control (ECN) networks. Transmen also had weaker connectivity compared with cisgender men between intra-SN regions and weaker inter-network connectivity between regions of the SN, the default mode network (DMN), the ECN and the sensorimotor network. Transwomen had lower small-worldness, modularity and clustering coefficient than cisgender men. There were no differences among transmen, transwomen, and ciswomen. Together these results underline the importance of the SN interacting with DMN, ECN, and sensorimotor networks in transmen, involving regions of the entire brain with a frontal predominance. Reduced global connectivity graph-theoretical measures were a characteristic of transwomen. It is proposed that the interaction between networks is a keystone in building a gendered self. Finally, our findings suggest that both proposed hypotheses are complementary in explaining brain differences between gender variants.

PMID: 32057995 [PubMed - as supplied by publisher]

Abnormal functional connectivity density in patients with major depressive disorder with comorbid insomnia.

Sat, 02/15/2020 - 15:20
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Abnormal functional connectivity density in patients with major depressive disorder with comorbid insomnia.

J Affect Disord. 2020 Jan 24;266:417-423

Authors: Gong L, Xu R, Liu D, Zhang C, Huang Q, Zhang B, Xi C

Abstract
BACKGROUND: Insomnia is a common comorbidity symptom in patients with major depressive disorder (MDD). However, the brain functional alteration in MDD with higher level insomnia (MDD-HI) and lower level insomnia (MDD-LI) remains unclear. Here, we investigated the association of insomnia with global functional connectivity density (gFCD) in patients with MDD.
METHODS: A total of 148 participants were recruited and underwent resting-state functional magnetic resonance imaging. A voxel-wise analysis of covariance was employed to explore group differences in gFCD among the MDD-HI, MDD-LI and healthy control (HC) groups.
RESULTS: The gFCD in the bilateral parahippocampal/hippocampal gyri (PHG/HIP) was higher in the two MDD than in the HC group, and it was higher in the MDD-LI than in the MDD-HI group; the gFCD in the left fusiform area was lower in the MDD than in the HC group. The gFCD in the left inferior temporal gyrus (ITG) was higher in the MDD-HI than in the MDD-LI and HC groups. The gFCD in the left ITG and posterior PHG/HIP was associated with insomnia, while the gFCD in the left anterior PHG/HIP was correlated with non-insomnia depressive symptoms in the MDD group.
LIMITATIONS: The cross-sectional design and the use of brief/subjective insomnia assessments.
CONCLUSIONS: The present study showed that the abnormal brain features of MDD with different insomnia symptom. Importantly, the posterior and anterior parts of the hippocampus may play different roles in the presence or absence of insomnia in patients with MDD.

PMID: 32056908 [PubMed - as supplied by publisher]

The relationship between sleep efficiency and clinical symptoms is mediated by brain function in major depressive disorder.

Sat, 02/15/2020 - 15:20
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The relationship between sleep efficiency and clinical symptoms is mediated by brain function in major depressive disorder.

J Affect Disord. 2020 Jan 28;266:327-337

Authors: Zhu DM, Zhang C, Yang Y, Zhang Y, Zhao W, Zhang B, Zhu J, Yu Y

Abstract
BACKGROUND: Sleep disturbance is a common and key symptom that affects most of patients with major depressive disorder (MDD). However, neural substrates underlying sleep disturbance and their clinical relevance in depression remain unclear.
METHODS: Ninety-six MDD patients underwent resting-state functional MRI. Fractional amplitude of low-frequency fluctuation (fALFF) and resting-state functional connectivity (rsFC) were used to measure brain function. Overnight polysomnography was performed to objectively measure sleep efficiency (SE), which was used to classify patients into normal sleep efficiency (NSE) and low sleep efficiency (LSE) groups. Between-group differences in fALFF and rsFC were examined using two-sample t-tests. Moreover, correlation and mediation analyses were conducted to test for potential associations between SE, brain functional changes, and clinical variables.
RESULTS: LSE group showed decreased fALFF in right cuneus, thalamus, and middle temporal gyrus compared to NSE group. MDD patients with low SE also exhibited lower rsFC of right cuneus to right lateral temporal cortex, which was associated with more severe depression and anxiety symptoms. More importantly, mediation analyses revealed that the relationships between SE and severity of depression and anxiety symptoms were significantly mediated by the altered rsFC. In addition, these low SE-related brain functional alterations were not affected by antidepressant medication and were independent of structural changes.
LIMITATIONS: The lack of healthy controls because of "first-night effect".
CONCLUSION: These findings not only may expand existing knowledge about neuropathology of sleep disturbance in depression, but also may inform real-world clinical practice by improving depression and anxiety symptoms through sleep regulation.

PMID: 32056895 [PubMed - as supplied by publisher]

Thalamocortical connectivity in electroconvulsive therapy for major depressive disorder.

Sat, 02/15/2020 - 15:20
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Thalamocortical connectivity in electroconvulsive therapy for major depressive disorder.

J Affect Disord. 2020 Mar 01;264:163-171

Authors: Wei Q, Bai T, Brown EC, Xie W, Chen Y, Ji G, Ramasubbu R, Tian Y, Wang K

Abstract
BACKGROUND: Electroconvulsive therapy (ECT) can lead to rapid and effective responses in major depressive disorder (MDD). However, the precise neural mechanisms of ECT for MDD are still unclear. Previous work has confirmed that thalamocortical circuits play an important role in emotion and cognition. However, the relationship between mechanisms of ECT for MDD and thalamocortical connectivity has not yet been investigated.
METHOD: Thalamocortical functional connectivity analysis was performed on resting-state functional magnetic resonance imaging (fMRI) data collected from 28 MDD patients both pre- and post-ECT treatment, as well as 20 healthy controls. The cortex was parceled into six regions of interest (ROIs), which were used as seeds to assess the functional connectivity between the cortex and each voxel in the thalamus. Then, functional connectivity between the identified thalamic subregions and the rest of the brain was quantified to better localize thalamocortical connectivity related to ECT. Structural connectivity among the functionally abnormal regions was also determined using probabilistic tractography from diffusion tensor imaging (DTI) data.
RESULTS: There was decreased parietal cortex-left pulvinar and left pulvinar-bilateral precuneus functional connectivity in post-ECT MDD patients, compared to pre-ECT MDD patients. Furthermore, functional connectivity strength of parietal cortex-left pulvinar and left pulvinar-bilateral precuneus was negative correlation with verbal fluency test scores in post-ECT MDD patients. No significant change was found in structural connectivity analysis.
LIMITATIONS: The sample size of our study was not large.
CONCLUSION: Our findings implicate that the specific abnormalities in thalamocortical circuit may be associated with cognitive impairment induced by ECT.

PMID: 32056746 [PubMed - in process]

Is Low-Grade Intraventricular Hemorrhage in Very Preterm Infants an Innocent Condition? Structural and Functional Evaluation of the Brain Reveals Regional Neurodevelopmental Abnormalities.

Sat, 02/15/2020 - 15:20
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Is Low-Grade Intraventricular Hemorrhage in Very Preterm Infants an Innocent Condition? Structural and Functional Evaluation of the Brain Reveals Regional Neurodevelopmental Abnormalities.

AJNR Am J Neuroradiol. 2020 Feb 13;:

Authors: Argyropoulou MI, Astrakas LG, Xydis VG, Drougia A, Mouka V, Goel I, Giapros V, Andronikou S

Abstract
BACKGROUND AND PURPOSE: There is increasing evidence of abnormal neurodevelopmental outcomes in very preterm infants with low-grade intraventricular hemorrhage grades I and II. Our purpose was to evaluate the effects of low-grade intraventricular hemorrhage on gray and white matter integrity.
MATERIALS AND METHODS: MR imaging at around term-equivalent age was performed in 16 very preterm infants (mean gestational age, 28.8 ± 5.3 weeks) with mild intraventricular hemorrhage on brain sonography and 13 control subjects (mean gestational age, 29.6 ± 4.1 weeks) without intraventricular hemorrhage. Structural and functional evaluation of the cortex was performed using regional measurements of surface area, thickness and volume, and resting-state fMRI, respectively, and of WM microstructural integrity, applying Tract-Based Spatial Statistics to diffusion tensor imaging data.
RESULTS: Compared with the control infants, the infants with low-grade intraventricular hemorrhage had decreases in the following: 1) GM surface area in Brodmann areas 19 left and 9 and 45 right, and GM volume in Brodmann areas 9 and 10 right; 2) fractional anisotropy bilaterally in major WM tracts; and 3) brain activity in the left lower lateral and in the right higher medial somatosensory cortex.
CONCLUSIONS: Very premature infants with low-grade intraventricular hemorrhage at around term-equivalent age may present with regional abnormalities, appearing on imaging studies as cortical underdevelopment, functional impairment, and microstructural immaturity of major WM tracts.

PMID: 32054617 [PubMed - as supplied by publisher]

Functional and Structural Connectivity Patterns Associated with Clinical Outcomes in Deep Brain Stimulation of the Globus Pallidus Internus for Generalized Dystonia.

Sat, 02/15/2020 - 15:20
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Functional and Structural Connectivity Patterns Associated with Clinical Outcomes in Deep Brain Stimulation of the Globus Pallidus Internus for Generalized Dystonia.

AJNR Am J Neuroradiol. 2020 Feb 13;:

Authors: Okromelidze L, Tsuboi T, Eisinger RS, Burns MR, Charbel M, Rana M, Grewal SS, Lu CQ, Almeida L, Foote KD, Okun MS, Middlebrooks EH

Abstract
BACKGROUND AND PURPOSE: Deep brain stimulation is a well-established treatment for generalized dystonia, but outcomes remain variable. Establishment of an imaging marker to guide device targeting and programming could possibly impact the efficacy of deep brain stimulation in dystonia, particularly in the absence of acute clinical markers to indicate benefit. We hypothesize that the stimulation-based functional and structural connectivity using resting-state fMRI and DTI can predict therapeutic outcomes in patients with generalized dystonia and deep brain stimulation.
MATERIALS AND METHODS: We performed a retrospective analysis of 39 patients with inherited or idiopathic-isolated generalized dystonia who underwent bilateral globus pallidus internus deep brain stimulation. After electrode localization, the volumes of tissue activated were modeled and used as seed regions for functional and structural connectivity measures using a normative data base. Resulting connectivity maps were correlated with postoperative improvement in the Unified Dystonia Rating Scale score.
RESULTS: Structural connectivity between the volumes of tissue activated and the primary sensorimotor cortex was correlated with Unified Dystonia Rating Scale improvement, while more anterior prefrontal connectivity was inversely correlated with Unified Dystonia Rating Scale improvement. Functional connectivity between the volumes of tissue activated and primary sensorimotor regions, motor thalamus, and cerebellum was most correlated with Unified Dystonia Rating Scale improvement; however, an inverse correlation with Unified Dystonia Rating Scale improvement was seen in the supplemental motor area and premotor cortex.
CONCLUSIONS: Functional and structural connectivity with multiple nodes of the motor network is associated with motor improvement in patients with generalized dystonia undergoing deep brain stimulation. Results from this study may serve as a basis for future development of clinical markers to guide deep brain stimulation targeting and programming in dystonia.

PMID: 32054614 [PubMed - as supplied by publisher]

Intrinsic differences in insular circuits moderate nicotine dependent reductions in cingulate-striatal connectivity strength.

Fri, 02/14/2020 - 14:40
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Intrinsic differences in insular circuits moderate nicotine dependent reductions in cingulate-striatal connectivity strength.

Neuropsychopharmacology. 2020 Feb 13;:

Authors: Keeley RJ, Hsu LM, Brynildsen JK, Lu H, Yang Y, Stein EA

Abstract
The development of brain-based biomarkers to assess nicotine dependence severity and treatment efficacy are essential to improve the current marginally effective treatment outcomes. Cross-sectional resting state functional connectivity (rsFC) studies in humans identified a circuit between the dorsal anterior cingulate cortex and the ventral striatum that negatively correlated with increased nicotine dependence severity but was unaffected by acute nicotine administration, suggesting a trait marker of addiction. However, whether this trait circuit dysregulation is predispositional to or resultant from nicotine dependence is unclear. Using a rat model of nicotine dependence with longitudinal fMRI measurements, we assessed the relationship between ACC-striatal rsFC and nicotine dependence severity. Data-driven modularity-based parcellation of the rat medial prefrontal cortex (mPFC) combined with seed-based connectivity analysis with the striatum recapitulated the cingulate-striatum relationship observed in humans. Furthermore, the relationship between cingulate-striatal brain circuits and nicotine dependence severity as indexed by the intensity of precipitated withdrawal, was fully statistically moderated by a predispositional insular-frontal cortical functional circuit. These data suggest that the identified trans-species ACC-striatal circuit relationship with nicotine dependence severity is dysregulated following chronic nicotine administration-induced dependence and may be biased by individual differences in predispositional insula-based striatal-frontal circuits, highlighting the circuit's potential as a biomarker of dependence severity.

PMID: 32053829 [PubMed - as supplied by publisher]

Evaluating Mechanisms of Postoperative Delirium and Cognitive Dysfunction Following Elective Spine Surgery in Elderly Patients (CONFESS): Protocol for a Prospective Observational Trial.

Fri, 02/14/2020 - 14:40
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Evaluating Mechanisms of Postoperative Delirium and Cognitive Dysfunction Following Elective Spine Surgery in Elderly Patients (CONFESS): Protocol for a Prospective Observational Trial.

JMIR Res Protoc. 2020 Feb 13;9(2):e15488

Authors: Müller J, Fleischmann R, Nowak S, Vogelgesang A, von Sarnowski B, Rathmann E, Schmidt S, Rehberg S, Usichenko T, Kertscho H, Hahnenkamp K, Flöel A, Schroeder HW, Müller JU

Abstract
BACKGROUND: Elderly people are at particular high risk for postoperative delirium (POD) following spine surgery, which is associated with longer hospital stays, higher costs, risk for delayed complications, long-term care dependency, and cognitive dysfunction (POCD). It is insufficiently understood which mechanisms and risk factors contribute to the development of POD and POCD following these major but plannable surgeries.
OBJECTIVE: This study aims to identify modifiable risk factors in spine surgery. A better understanding thereof would help adapt medical management and surgical strategies to individual risk profiles.
METHODS: This is a single-center observational study jointly conducted by the departments of neurosurgery, neurology, and anesthesiology at a tertiary care hospital in Germany. All patients aged 60 years and older presenting to the neurosurgery outpatient clinic or ward for elective spine surgery are screened for eligibility. Exclusion criteria include presence of neurodegenerative or history of psychiatric disease and medication with significant central nervous system activity (eg, antidepressants, antipsychotics, sedatives). Surgical and anesthetic procedures including duration of surgery as primary end point of this study are thoroughly documented. All patients are furthermore evaluated for their preoperative cognitive abilities by a number of tests, including the Consortium to Establish a Registry for Alzheimer's Disease Plus test battery. Physical, mental, and social health and well-being are assessed using the Patient-Reported Outcome Measurement Information System Profile 29 and Hospital Anxiety and Depression Scale. Patients additionally receive preoperative cerebrovascular ultrasound and structural and functional brain imaging. The immediate postoperative period includes screening for POD using the Nursing Delirium Screening Scale and validation through Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, criteria. We furthermore investigate markers of (neuro)inflammation (eg, interleukins, C-reactive protein, tumor necrosis factor alpha). Preoperative examinations are repeated 3 months postoperatively to investigate the presence of POCD and its mechanisms. Statistical analyses will compare delirious and nondelirious patients for predictors of immediate (POD) and delayed (POCD) cognitive dysfunction.
RESULTS: This is the first study to prospectively evaluate risk factors for POD and POCD in spine surgery. Recruitment is ongoing, and data collection is estimated to be finished with the inclusion of 200 patients by mid-2020.
CONCLUSIONS: The identification of mechanisms, possibly common, underlying POD and POCD would be a major step toward defining effective interventional strategies early in or even before the postoperative period, including the adaptation of surgical strategies to individual risk profiles.
TRIAL REGISTRATION: ClinicalTrials.gov NCT03486288; https://clinicaltrials.gov/ct2/show/NCT03486288.
INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/15488.

PMID: 32053113 [PubMed]

Disrupted Time-Dependent and Functional Connectivity Brain Network in Alzheimer's Disease: A Resting-State fMRI Study Based on Visibility Graph.

Fri, 02/14/2020 - 14:40
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Disrupted Time-Dependent and Functional Connectivity Brain Network in Alzheimer's Disease: A Resting-State fMRI Study Based on Visibility Graph.

Curr Alzheimer Res. 2020 Feb 12;:

Authors: Gao Z, Feng Y, Ma C, Ma K, Cai Q

Abstract
BACKGROUND: Alzheimer's disease (AD) is a progressive neurodegenerative disease with insidious onset, which is difficult to be reversed and cured. Therefore, discovering more precise biological information from neuroimaging biomarkers is crucial for accurate and automatic detection of AD.
METHODS: We innovatively used a visibility graph (VG) to construct the time-dependent brain networks as well as functional connectivity network to investigate the underlying dynamics of AD brain based on functional magnetic resonance imaging. There were 32 AD patients and 29 normal controls (NCs) from the Alzheimer's disease neuroimaging initiative (ADNI) database. First, the VG method mapped the time series of single brain region into networks. By extracting topological properties of the networks, the most significant features were selected as discriminant features into a supporting vector machine for classification. Furthermore, in order to detect abnormalities of these brain regions in the whole AD brain, functional connectivity among different brain regions was calculated based on the correlation of regional degree sequences.
RESULTS: According to the topology abnormalities exploration of local complex networks, we found several abnormal brain regions, including left insular, right posterior cingulate gyrus and other cortical regions. The accuracy of characteristics of the brain regions extracted from local complex networks was 88.52%. Association analysis demonstrated that the left inferior opercular part of frontal gyrus, right middle occipital gyrus, right superior parietal gyrus and right precuneus played a tremendous role in AD.
CONCLUSION: These results would be helpful in revealing the underlying pathological mechanism of the disease.

PMID: 32053076 [PubMed - as supplied by publisher]

Real-time biofeedback integrated into neuromuscular training reduces high-risk knee biomechanics and increases functional brain connectivity: A preliminary longitudinal investigation.

Fri, 02/14/2020 - 14:40
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Real-time biofeedback integrated into neuromuscular training reduces high-risk knee biomechanics and increases functional brain connectivity: A preliminary longitudinal investigation.

Psychophysiology. 2020 Feb 13;:e13545

Authors: Diekfuss JA, Grooms DR, Bonnette S, DiCesare CA, Thomas S, MacPherson RP, Ellis JD, Kiefer AW, Riley MA, Schneider DK, Gadd B, Kitchen K, Barber Foss KD, Dudley JA, Yuan W, Myer GD

Abstract
Prospective evidence indicates that functional biomechanics and brain connectivity may predispose an athlete to an anterior cruciate ligament injury, revealing novel neural linkages for targeted neuromuscular training interventions. The purpose of this study was to determine the efficacy of a real-time biofeedback system for altering knee biomechanics and brain functional connectivity. Seventeen healthy, young, physically active female athletes completed 6 weeks of augmented neuromuscular training (aNMT) utilizing real-time, interactive visual biofeedback and 13 served as untrained controls. A drop vertical jump and resting state functional magnetic resonance imaging were separately completed at pre- and posttest time points to assess sensorimotor adaptation. The aNMT group had a significant reduction in peak knee abduction moment (pKAM) compared to controls (p = .03, d = 0.71). The aNMT group also exhibited a significant increase in functional connectivity between the right supplementary motor area and the left thalamus (p = .0473 after false discovery rate correction). Greater percent change in pKAM was also related to increased connectivity between the right cerebellum and right thalamus for the aNMT group (p = .0292 after false discovery rate correction, r2  = .62). No significant changes were observed for the controls (ps > .05). Our data provide preliminary evidence of potential neural mechanisms for aNMT-induced motor adaptations that reduce injury risk. Future research is warranted to understand the role of neuromuscular training alone and how each component of aNMT influences biomechanics and functional connectivity.

PMID: 32052868 [PubMed - as supplied by publisher]

Dysbalanced Resting-State Functional Connectivity Within the Praxis Network Is Linked to Gesture Deficits in Schizophrenia.

Fri, 02/14/2020 - 14:40
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Dysbalanced Resting-State Functional Connectivity Within the Praxis Network Is Linked to Gesture Deficits in Schizophrenia.

Schizophr Bull. 2020 Feb 13;:

Authors: Wüthrich F, Viher PV, Stegmayer K, Federspiel A, Bohlhalter S, Vanbellingen T, Wiest R, Walther S

Abstract
Patients with schizophrenia frequently present deficits in gesture production and interpretation, greatly affecting their communication skills. As these gesture deficits can be found early in the course of illness and as they can predict later outcomes, exploring their neural basis may lead to a better understanding of schizophrenia. While gesturing has been reported to rely on a left lateralized network of brain regions, termed praxis network, in healthy subjects and lesioned patients, studies in patients with schizophrenia are sparse. It is currently unclear whether within-network connectivity at rest is linked to gesture deficit. Here, we compared the functional connectivity between regions of the praxis network at rest between 46 patients and 44 healthy controls. All participants completed a validated test of hand gesture performance before resting-state functional magnetic resonance imaging (fMRI) was acquired. Patients performed gestures poorer than controls in all categories and domains. In patients, we also found significantly higher resting-state functional connectivity between left precentral gyrus and bilateral superior and inferior parietal lobule. Likewise, patients had higher connectivity from right precentral gyrus to left inferior and bilateral superior parietal lobule (SPL). In contrast, they exhibited lower connectivity between bilateral superior temporal gyrus (STG). Connectivity between right precentral gyrus and left SPL, as well as connectivity between bilateral STG, correlated with gesture performance in healthy controls. We failed to detect similar correlations in patients. We suggest that altered resting-state functional connectivity within the praxis network perturbs correct gesture planning in patients, reflecting the gesture deficit often seen in schizophrenia.

PMID: 32052844 [PubMed - as supplied by publisher]

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