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Altered Global Synchronizations in Patients With Parkinson's Disease: A Resting-State fMRI Study.

Sat, 07/13/2019 - 03:26

Altered Global Synchronizations in Patients With Parkinson's Disease: A Resting-State fMRI Study.

Front Aging Neurosci. 2019;11:139

Authors: Li M, Liu Y, Chen H, Hu G, Yu S, Ruan X, Luo Z, Wei X, Xie Y

Abstract
Background: Abnormalities of cognitive and movement functions are widely reported in Parkinson's disease (PD). The mechanisms therein are complicated and assumed to a coordination of various brain regions. This study explored the alterations of global synchronizations of brain activities and investigated the neural correlations of cognitive and movement function in PD patients. Methods: Thirty-five age-matched patients with PD and 35 normal controls (NC) were enrolled in resting-state functional magnetic resonance imaging (rs-fMRI) scanning. Degree centrality (DC) was calculated to measure the global synchronizations of brain activity for two groups. Neural correlations between DC and cognitive function Frontal Assessment Battery (FAB), as well as movement function Unified Parkinson's Disease Rating Scale (UPDRS-III), were examined across the whole brain within Anatomical Automatic Labeling (AAL) templates. Results: In the PD group, increased DC was observed in left fusiform gyrus extending to inferior temporal gyrus, left middle temporal gyrus (MTG) and angular gyrus, while it was decreased in right inferior opercular-frontal gyrus extending to superior temporal gyrus (STG). The DC in a significant region of the fusiform gyrus was positively correlated with UPDRS-III scores in PD (r = 0.41, p = 0.0145). Higher FAB scores were shown in NC than PD (p < 0.0001). Correlative analysis of PD between DC and FAB showed negative results (p < 0.05) in frontal cortex, whereas positive in insula and cerebellum. As for the correlations between DC and UPDRS-III, negative correlation (p < 0.05) was observed in bilateral inferior parietal lobule (IPL) and right cerebellum, whereas positive correlation (p < 0.05) in bilateral hippocampus and para-hippocampus gyrus (p < 0.01). Conclusion: The altered global synchronizations revealed altered cognitive and movement functions in PD. The findings suggested that the global functional connectivity in fusiform gyrus, cerebellum and hippocampus gyrus are critical regions in the identification of cognitive and movement functions in PD. This study provides new insights on the interactions among global coordination of brain activity, cognitive and movement functions in PD.

PMID: 31293411 [PubMed]

Neuroplastic Effects in Patients With Traumatic Brain Injury After Music-Supported Therapy.

Sat, 07/13/2019 - 03:26

Neuroplastic Effects in Patients With Traumatic Brain Injury After Music-Supported Therapy.

Front Hum Neurosci. 2019;13:177

Authors: Vik BMD, Skeie GO, Specht K

Abstract
Damage to the orbitofrontal cortex (OFC) often occurs following a traumatic brain injury (TBI) and can lead to complex behavioral changes, including difficulty with attention and concentration. We investigated the effects of musical training on patients with behavioral and cognitive deficits following a mild traumatic brain injury (mTBI) and found significant functional neuro-plastic changes in the OFC's networks. The results from neuropsychological tests revealed an improved cognitive performance. Moreover, six out of seven participants in this group returned to work post intervention and reported improved well-being and social behavior. In this study, we explore the functional changes in OFC following music-supported intervention in reference to connecting networks that may be responsible for enhanced social interaction. Furthermore, we discuss the factor of dopamine release during playing as an element providing a possible impact on the results. The intervention consisted of playing piano, two sessions per week in 8 weeks, 30 min each time, with an instructor. Additional playing was required with a minimum of 15 min per day at home. Mean time playing piano in reference to participant's report was 3 h per week during the intervention period. Three groups participated, one mTBI group (n = 7), two control groups consisting of healthy participants, one with music training (n = 11), and one baseline group without music training (n = 12). Participants in the clinical group had received standardized cognitive rehabilitation treatment during hospitalization without recovering from their impairments. The intervention took place 2 years post injury. All participants were assessed with neuropsychological tests and with both task and resting-state functional magnetic resonance imaging (fMRI) pre-post intervention. The results demonstrated a significant improvement of neuropsychological tests in the clinical group, consistent with fMRI results in which there were functional changes in the orbitofrontal networks (OFC). These changes were concordantly seen both in a simple task fMRI but also in resting-state fMRI, which was analyzed with dynamic causal modeling (DCM). We hypothesized that playing piano, as designed in the training protocol, may provide a positive increase in both well-being and social interaction. We suggest that the novelty of the intervention may have clinical relevance for patients with behavioral problems following a TBI.

PMID: 31293405 [PubMed]

Semiparametric Estimation of Task-Based Dynamic Functional Connectivity on the Population Level.

Sat, 07/13/2019 - 03:26

Semiparametric Estimation of Task-Based Dynamic Functional Connectivity on the Population Level.

Front Neurosci. 2019;13:583

Authors: Kudela MA, Dzemidzic M, Oberlin BG, Lin Z, Goñi J, Kareken DA, Harezlak J

Abstract
Dynamic functional connectivity (dFC) estimates time-dependent associations between pairs of brain region time series as typically acquired during functional MRI. dFC changes are most commonly quantified by pairwise correlation coefficients between the time series within a sliding window. Here, we applied a recently developed bootstrap-based technique (Kudela et al., 2017) to robustly estimate subject-level dFC and its confidence intervals in a task-based fMRI study (24 subjects who tasted their most frequently consumed beer and Gatorade as an appetitive control). We then combined information across subjects and scans utilizing semiparametric mixed models to obtain a group-level dFC estimate for each pair of brain regions, flavor, and the difference between flavors. The proposed approach relies on the estimated group-level dFC accounting for complex correlation structures of the fMRI data, multiple repeated observations per subject, experimental design, and subject-specific variability. It also provides condition-specific dFC and confidence intervals for the whole brain at the group level. As a summary dFC metric, we used the proportion of time when the estimated associations were either significantly positive or negative. For both flavors, our fully-data driven approach yielded regional associations that reflected known, biologically meaningful brain organization as shown in prior work, as well as closely resembled resting state networks (RSNs). Specifically, beer flavor-potentiated associations were detected between several reward-related regions, including the right ventral striatum (VST), lateral orbitofrontal cortex, and ventral anterior insular cortex (vAIC). The enhancement of right VST-vAIC association by a taste of beer independently validated the main activation-based finding (Oberlin et al., 2016). Most notably, our novel dFC methodology uncovered numerous associations undetected by the traditional static FC analysis. The data-driven, novel dFC methodology presented here can be used for a wide range of task-based fMRI designs to estimate the dFC at multiple levels-group-, individual-, and task-specific, utilizing a combination of well-established statistical methods.

PMID: 31293367 [PubMed]

Differential functional patterns of the human posterior cingulate cortex during activation and deactivation: a meta-analytic connectivity model.

Sat, 07/13/2019 - 03:26

Differential functional patterns of the human posterior cingulate cortex during activation and deactivation: a meta-analytic connectivity model.

Exp Brain Res. 2019 Jul 10;:

Authors: Busler JN, Yanes JA, Bird RT, Reid MA, Robinson JL

Abstract
The posterior cingulate cortex (PCC) has been implicated in a host of cognitive and behavioral processes in addition to serving as a central hub in the default mode network (DMN). Moreover, the PCC has been shown to be involved in a range of psychiatric and neurological disorders. However, very little is known about the specific activated/deactivated functional profiles of the PCC. Here, we employed a dual analytic approach using robust quantitative meta-analytical connectivity modeling (MACM) and ultra-high field, high resolution resting state functional magnetic resonance imaging (rs-fMRI) to identify state-specific functional activity patterns of the human PCC. The MACM results provided evidence for regions of convergence for PCC co-activation and co-deactivation (i.e., left medial frontal gyrus, left amygdala, and left anterior cingulate) as well as regions of divergence specific to either PCC activation (i.e., bilateral inferior frontal gyri) or PCC deactivation (i.e., left parahippocampal gyrus). In addition, exploratory MACMs on dorsal and ventral subregions of the PCC revealed differential functional activity patterns such as greater co-activation of the right PCC and left inferior parietal lobule with the dorsal PCC and greater co-activation of right precuneus with the ventral PCC. Resting state connectivity analyses showed widespread connectivity similar to that of the PCC co-activation-based MACM, but also demonstrated additional regions of activity, including bilateral superior parietal regions and right superior temporal regions. These analyses highlight the diverse neurofunctional repertoire of the human PCC, provide additional insight into its dynamic functional activity patterns as it switches between activated and deactivated states, and elucidates the cognitive processes that may be implicated in clinical populations.

PMID: 31292696 [PubMed - as supplied by publisher]

Early postpartum resting-state functional connectivity for mothers receiving buprenorphine treatment for opioid use disorder: A Pilot Study.

Thu, 07/11/2019 - 03:24

Early postpartum resting-state functional connectivity for mothers receiving buprenorphine treatment for opioid use disorder: A Pilot Study.

J Neuroendocrinol. 2019 Jul 09;:e12770

Authors: Swain JE, Ho SS

Abstract
OBJECTIVE: Between 1999 and 2014, the prevalence of opioid use disorder (OUD) among pregnant women quadrupled in the U.S. The standard treatment for peripartum women with OUD is buprenorphine. However, the Maternal Behavior Neurocircuit, that regulates maternal behavior and mother-infant bonding, has not been previously studied for human mothers receiving buprenorphine treatment for OUD (BT). Rodent research shows opioid effects on reciprocal inhibition between maternal care and defense maternal brain subsystems: hypothalamus and periaqueductal gray respectively. We conducted a longitudinal functional magnetic resonance imaging (fMRI) pilot study in humans to specifically examine resting-state functional connectivity (rs-FC) between periaqueductal gray and hypothalamus, and explore associations with maternal bonding for BT.
METHODS: We studied 32 mothers who completed fMRI scans at 1-month (T1) and 4-months postpartum (T2), including 7 mothers receiving buprenorphine for OUD and 25 non-OUD mothers as a comparison group (CG). The participants underwent a 6-minute resting-state fMRI scan at each time point. We measured potential bonding impairments with the Postpartum Bonding Questionnaire to explore how rs-FC with periaqueductal gray is associated with bonding impairments.
RESULTS: As compared to CG, BT mothers differed in periaqueductal gray-dependent rs-FC with the hypothalamus, amygdala, insular cortex, and other brain regions at T1 and many of these differences disappeared at T2, suggesting potential therapeutic effects of continuing buprenorphine treatment. Also, the "rejection and pathological anger" subscale of Postpartum Bonding Questionnaire at T1 and T2 were associated with the T1-to-T2 increases in periaqueductal gray-dependent rs-FC with the hypothalamus and amygdala.
CONCLUSION: Preliminary evidence links maternal bonding problems for mothers with OUD early in the postpartum to connectivity between specific care and defense maternal brain circuits, which may be mitigated by buprenorphine treatment. This exploratory study supports a potential mechanism to study both therapeutic benefits and risks of opioids for maternal care and bonding with infants. This article is protected by copyright. All rights reserved.

PMID: 31287922 [PubMed - as supplied by publisher]

An information network flow approach for measuring functional connectivity and predicting behavior.

Thu, 07/11/2019 - 03:24

An information network flow approach for measuring functional connectivity and predicting behavior.

Brain Behav. 2019 Jul 09;:e01346

Authors: Kumar S, Yoo K, Rosenberg MD, Scheinost D, Constable RT, Zhang S, Li CR, Chun MM

Abstract
INTRODUCTION: Connectome-based predictive modeling (CPM) is a recently developed machine-learning-based framework to predict individual differences in behavior from functional brain connectivity (FC). In these models, FC was operationalized as Pearson's correlation between brain regions' fMRI time courses. However, Pearson's correlation is limited since it only captures linear relationships. We developed a more generalized metric of FC based on information flow. This measure represents FC by abstracting the brain as a flow network of nodes that send bits of information to each other, where bits are quantified through an information theory statistic called transfer entropy.
METHODS: With a sample of individuals performing a sustained attention task and resting during functional magnetic resonance imaging (fMRI) (n = 25), we use the CPM framework to build machine-learning models that predict attention from FC patterns measured with information flow. Models trained on n - 1 participants' task-based patterns were applied to an unseen individual's resting-state pattern to predict task performance. For further validation, we applied our model to two independent datasets that included resting-state fMRI data and a measure of attention (Attention Network Task performance [n = 41] and stop-signal task performance [n = 72]).
RESULTS: Our model significantly predicted individual differences in attention task performance across three different datasets.
CONCLUSIONS: Information flow may be a useful complement to Pearson's correlation as a measure of FC because of its advantages for nonlinear analysis and network structure characterization.

PMID: 31286688 [PubMed - as supplied by publisher]

Generalizability and reproducibility of functional connectivity in autism.

Thu, 07/11/2019 - 03:24

Generalizability and reproducibility of functional connectivity in autism.

Mol Autism. 2019;10:27

Authors: King JB, Prigge MBD, King CK, Morgan J, Weathersby F, Fox JC, Dean DC, Freeman A, Villaruz JAM, Kane KL, Bigler ED, Alexander AL, Lange N, Zielinski B, Lainhart JE, Anderson JS

Abstract
Background: Autism is hypothesized to represent a disorder of brain connectivity, yet patterns of atypical functional connectivity show marked heterogeneity across individuals.
Methods: We used a large multi-site dataset comprised of a heterogeneous population of individuals with autism and typically developing individuals to compare a number of resting-state functional connectivity features of autism. These features were also tested in a single site sample that utilized a high-temporal resolution, long-duration resting-state acquisition technique.
Results: No one method of analysis provided reproducible results across research sites, combined samples, and the high-resolution dataset. Distinct categories of functional connectivity features that differed in autism such as homotopic, default network, salience network, long-range connections, and corticostriatal connectivity, did not align with differences in clinical and behavioral traits in individuals with autism. One method, lag-based functional connectivity, was not correlated to other methods in describing patterns of resting-state functional connectivity and their relationship to autism traits.
Conclusion: Overall, functional connectivity features predictive of autism demonstrated limited generalizability across sites, with consistent results only for large samples. Different types of functional connectivity features do not consistently predict different symptoms of autism. Rather, specific features that predict autism symptoms are distributed across feature types.

PMID: 31285817 [PubMed - in process]

Modulation of the spontaneous hemodynamic response function across levels of consciousness.

Thu, 07/11/2019 - 03:24
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Modulation of the spontaneous hemodynamic response function across levels of consciousness.

Neuroimage. 2019 Jul 05;:

Authors: Wu GR, Di Perri C, Charland-Verville V, Martial C, Carrière M, Vanhaudenhuyse A, Laureys S, Marinazzo D

Abstract
Functional imaging research has already contributed with several results to the study of neural correlates of consciousness. Apart from task-related activation derived in fMRI, PET based glucose metabolism rate or cerebral blood flow account for a considerable proportion of the study of brain activity under different levels of consciousness. Resting state functional connectivity MRI is playing a crucial role to explore the consciousness related functional integration, successfully complementing PET, another widely used neuroimaging technique. Here, spontaneous hemodynamic response is introduced to characterize resting state brain activity giving information on the local metabolism (neurovascular coupling), and useful to improve the time-resolved activity and connectivity measures based on BOLD fMRI. This voxel-wise measure is then used to investigate the loss of consciousness under Propofol anesthesia and unresponsive wakefulness syndrome. Changes in the hemodynamic response in precuneus and posterior cingulate are found to be a common principle underlying loss of consciousness in both conditions. The thalamus appears to be less obviously modulated by Propofol, compared with frontoparietal regions. However, a significant increase in spontaneous thalamic hemodynamic response was found in patients in unresponsive wakefulness syndrome compared with healthy controls. Our results ultimately show that anesthesia- or pathology-induced neurovascular coupling could be tracked by modulated spontaneous hemodynamic response derived from resting state fMRI.

PMID: 31284028 [PubMed - as supplied by publisher]

Resting State Dynamic Functional Connectivity in Neurodegenerative Conditions: A Review of Magnetic Resonance Imaging Findings.

Thu, 07/11/2019 - 03:24
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Resting State Dynamic Functional Connectivity in Neurodegenerative Conditions: A Review of Magnetic Resonance Imaging Findings.

Front Neurosci. 2019;13:657

Authors: Filippi M, Spinelli EG, Cividini C, Agosta F

Abstract
In the last few decades, brain functional connectivity (FC) has been extensively assessed using resting-state functional magnetic resonance imaging (RS-fMRI), which is able to identify temporally correlated brain regions known as RS functional networks. Fundamental insights into the pathophysiology of several neurodegenerative conditions have been provided by studies in this field. However, most of these studies are based on the assumption of temporal stationarity of RS functional networks, despite recent evidence suggests that the spatial patterns of RS networks may change periodically over the time of an fMRI scan acquisition. For this reason, dynamic functional connectivity (dFC) analysis has been recently implemented and proposed in order to consider the temporal fluctuations of FC. These approaches hold promise to provide fundamental information for the identification of pathophysiological and diagnostic markers in the vast field of neurodegenerative diseases. This review summarizes the main currently available approaches for dFC analysis and reports their recent applications for the assessment of the most common neurodegenerative conditions, including Alzheimer's disease, Parkinson's disease, dementia with Lewy bodies, and frontotemporal dementia. Critical state-of-the-art findings, limitations, and future perspectives regarding the analysis of dFC in these diseases are provided from both a clinical and a technical point of view.

PMID: 31281241 [PubMed]

Cortical Alterations by the Abnormal Visual Experience beyond the Critical Period: A Resting-state fMRI Study on Constant Exotropia.

Thu, 07/11/2019 - 03:24
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Cortical Alterations by the Abnormal Visual Experience beyond the Critical Period: A Resting-state fMRI Study on Constant Exotropia.

Curr Eye Res. 2019 Jul 06;:

Authors: Shi H, Wang Y, Liu X, Xia L, Chen Y, Lu Q, Nguchu BA, Wang H, Qiu B, Wang X, Feng L

Abstract
Purpose: The pathological mechanisms of constant exotropia (XT) are still not understood. This study aimed to critically investigate whether patients with XT express neuronal activity changes after the critical period of visual development and further explore how these alterations are associated with behavioral performance. Materials and methods: Fourteen patients with XT and 16 healthy controls (HCs) underwent resting-state functional magnetic resonance imaging (fMRI). The regional homogeneity (ReHo) method was used to evaluate spontaneous brain activities. The association between significantly altered mean ReHo values and behavioral performance was assessed using Pearson's correlation analysis. Results: Compared with HCs, the right secondary visual cortex (V2) in patients with XT exhibited increased ReHo values, whereas the left Brodmann area 47 (BA47) demonstrated decreased spontaneous ReHo values. In patients with XT, the correlation between the left BA47's mean ReHo value and duration of strabismus was positively significant. Conclusions: These findings indicate that patients with XT have severe neural dysfunction in the right V2 and left BA47, and pathological severity in the left BA47 is likely influenced by duration of ongoing strabismus. Therefore, these results may provide clinically important information toward understanding the underlying pathological mechanisms of XT and thus can be fundamental in future XT research.

PMID: 31280612 [PubMed - as supplied by publisher]

Differential coupling between subcortical calcium and BOLD signals during evoked and resting state through simultaneous calcium fiber photometry and fMRI.

Mon, 07/08/2019 - 18:21
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Differential coupling between subcortical calcium and BOLD signals during evoked and resting state through simultaneous calcium fiber photometry and fMRI.

Neuroimage. 2019 Jul 04;:

Authors: Tong C, Dai JK, Chen Y, Zhang K, Feng Y, Liang Z

Abstract
Task based and resting state fMRI has been widely utilized to study brain functions. As the foundation of fMRI, the underlying neural basis of the BOLD signal has been extensively studied, but the detailed mechanism remains elusive, particularly during the resting state. To examine the neurovascular coupling, it is important to simultaneously record neural and vascular signals. Here we developed a novel setup of camera based, scalable simultaneous calcium fiber photometry and fMRI in rats. Using this setup, we recorded calcium signals of superior colliculus (SC) and lateral geniculate nucleus (LGN) and fMRI simultaneously during visual stimulation and the resting state. Our results revealed robust, region-specific coupling between calcium and BOLD signals in the task state and weaker, whole brain correlation in the resting state. Interestingly, the spatial specificity of such correlation in the resting state was improved upon regression of white matter, ventricle signals and global signals in fMRI data. Overall, our results suggest differential coupling of calcium and BOLD signals for subcortical regions between evoked and resting states, and the coupling relationship in the resting state was related with resting state BOLD preprocessing strategies.

PMID: 31280011 [PubMed - as supplied by publisher]

Cognitive reward control recruits medial and lateral frontal cortices, which are also involved in cognitive emotion regulation a coordinate-based meta-analysis of fMRI studies.

Mon, 07/08/2019 - 18:21
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Cognitive reward control recruits medial and lateral frontal cortices, which are also involved in cognitive emotion regulation a coordinate-based meta-analysis of fMRI studies.

Neuroimage. 2019 Jul 04;:

Authors: Brandl F, Le Houcq Corbi Z, Bratec SM, Sorg C

Abstract
Cognitive reward control (CRC) refers to the cognitive control of one's craving for hedonic stimuli, like food, sex, or drugs. Numerous functional magnetic resonance imaging (fMRI) studies have investigated neural sources of CRC. However, a consistent pattern of brain activation across stimulus types has not been identified so far. We addressed this question using coordinate-based meta-analysis of task-fMRI studies during CRC. To further characterize such a potential common CRC activation pattern, we extended our approach to three additional questions: (i) Do CRC meta-analytic results overlap with those during the control of emotional states, such as in cognitive regulation of aversive emotions (CER)? (ii) How does the control of motivational/emotional states link to the control of action states with less motivational/emotional valence such as in response inhibition paradigms, i.e., do meta-anyltic result maps overlap? (iii) Does the control of motivational/emotional states constitute a consistent pattern of organized (i.e., coherent) ongoing or intrinsic brain activity? This question was tested by a seed-based intrinsic functional connectivity (iFC) analysis in an independent data set of resting-state fMRI. We found consistent CRC activation mainly in supplementary motor, dorsolateral prefrontal, and ventrolateral prefrontal cortices across studies. This activation pattern overlapped largely with CER-related activation, except for left-sided lateral temporal and parietal cortex activation, which was more pronounced during CER. It overlapped partly with activation during response inhibition in (pre-)supplementary motor, insular, and parietal cortices, but differed from it in dorsolateral and ventrolateral prefrontal cortices. Furthermore, it remarkably defined an iFC network covering activation patterns of both CRC and CER. Results demonstrate a consistent activation pattern of CRC across stimulus types, which overlaps largely with those of CER but only partly with those of response inhibition and constitutes an intrinsic co-activity network. These data suggest a common mechanism for the cognitive control of both motivational and emotional stimuli.results.

PMID: 31280010 [PubMed - as supplied by publisher]

Transdiagnostic modulation of brain networks by electroconvulsive therapy in schizophrenia and major depression.

Mon, 07/08/2019 - 18:21
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Transdiagnostic modulation of brain networks by electroconvulsive therapy in schizophrenia and major depression.

Eur Neuropsychopharmacol. 2019 Jul 03;:

Authors: Sambataro F, Thomann PA, Nolte HM, Hasenkamp JH, Hirjak D, Kubera KM, Hofer S, Seidl U, Depping MS, Stieltje B, Maier-Hein K, Wolf RC

Abstract
Major depressive disorder (MDD) and schizophrenia (SCZ) share neurobiological and clinical commonalities. Altered functional connectivity of large-scale brain networks has been associated with both disorders. Electroconvulsive therapy (ECT) has proven to be an effective treatment in severe forms of MDD and SCZ. However, the role of ECT on the modulation of the dynamics of brain networks is still unknown. In this study, we used resting state functional magnetic resonance imaging (rs-fMRI) to investigate functional connectivity in 16 pharmacoresistant patients with SCZ or MDD and a matched group of normal controls. Patients were scanned before and after right-sided unilateral ECT. Group spatial independent component analysis was carried out with a multiple analysis of covariance (MANCOVA) approach to estimate the effects of ECT treatment on intrinsic components (INs). Functional network connectivity (FNC) was calculated between pairs of INs. Patients had reduced connectivity within a striato-thalamic network in the thalamus as well as increased low frequency oscillations in a striatal network. ECT reduced low frequency oscillations (LFOs) on a striatal network along with increasing functional connectivity in the medial prefrontal cortex within the DMN. Following ECT treatment, the FNC of the executive network was reduced with the DMN and increased with the salience network, respectively. Our findings suggest transnosological effects of ECT on the connectivity of large-scale networks as well as at the level of their interplay. Furthermore, they support a transnosological approach for the investigation not only of the neural correlates of the disease but also of the brain mechanism of treatment of mental disorders.

PMID: 31279591 [PubMed - as supplied by publisher]

The resting-brain of obsessive-compulsive disorder.

Sun, 07/07/2019 - 18:19
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The resting-brain of obsessive-compulsive disorder.

Psychiatry Res Neuroimaging. 2019 Jul 02;290:38-41

Authors: Moreira PS, Marques P, Magalhães R, Esteves M, Sousa N, Soares JM, Morgado P

Abstract
Obsessive-compulsive disorder (OCD) is one of the most debilitating psychiatric conditions, having a dramatic impact on patients' daily living. In this work, we aimed to explore resting-state functional connectivity in OCD patients, using an independent component analysis. Eighty individuals (40 patients and 40 healthy controls) performed a resting state fMRI protocol. OCD patients displayed reduced functional connectivity (FC) in visual and sensorimotor networks. In addition, patients displayed decreased FC between sensory networks and increased FC between default-mode and cerebellar networks.

PMID: 31279239 [PubMed - as supplied by publisher]

Transient subcortical functional connectivity upon emergence from propofol sedation in human male volunteers: evidence for active emergence.

Sun, 07/07/2019 - 18:19
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Transient subcortical functional connectivity upon emergence from propofol sedation in human male volunteers: evidence for active emergence.

Br J Anaesth. 2019 Jul 02;:

Authors: Nir T, Or-Borichev A, Izraitel E, Hendler T, Lerner Y, Matot I

Abstract
BACKGROUND: Emergence from sedation entails rapid increase in the levels of both awareness and wakefulness, the two axes of consciousness. Functional MRI (fMRI) studies of emergence from sedation often focus on the recovery period, with no description of the moment of emergence. We hypothesised that by focusing on the moment of emergence, novel insights, primarily about subcortical activity and increased wakefulness, will be gained.
METHODS: We conducted a resting state fMRI analysis of 17 male subjects (20-40 yr old) gradually entering into and emerging from deep sedation (average computed propofol concentrations of 2.41 and 1.11 μg ml-1, respectively), using target-controlled infusion of propofol.
RESULTS: Functional connectivity analysis revealed a robust spatiotemporal signature of return of consciousness, in which subcortical seeds showed transient positive correlations that rapidly turned negative shortly after emergence. Elements of this signature included four components of the ascending reticular activating system: the ventral tegmentum area, the locus coeruleus, median raphe, and the mammillary body. The involvement of the rostral dorsolateral pontine tegmentum, which is specifically impaired in comatose patients with pontine lesions, in emergence was previously unknown.
CONCLUSIONS: Emergence from propofol sedation is characterised, and possibly driven, by a transient activation of brainstem loci. Some of these loci are known components of the ascending reticular activating system, whereas an additional locus was found that is also impaired in comatose patients.

PMID: 31277837 [PubMed - as supplied by publisher]

Multivariate classification of drug-naive obsessive-compulsive disorder patients and healthy controls by applying an SVM to resting-state functional MRI data.

Sun, 07/07/2019 - 18:19
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Multivariate classification of drug-naive obsessive-compulsive disorder patients and healthy controls by applying an SVM to resting-state functional MRI data.

BMC Psychiatry. 2019 Jul 05;19(1):210

Authors: Yang X, Hu X, Tang W, Li B, Yang Y, Gong Q, Huang X

Abstract
BACKGROUND: Previous resting-state functional magnetic resonance imaging (rs-fMRI) studies have revealed intrinsic regional activity alterations in obsessive-compulsive disorder (OCD), but those results were based on group analyses, which limits their applicability to clinical diagnosis and treatment at the level of the individual.
METHODS: We examined fractional amplitude low-frequency fluctuation (fALFF) and applied support vector machine (SVM) to discriminate OCD patients from healthy controls on the basis of rs-fMRI data. Values of fALFF, calculated from 68 drug-naive OCD patients and 68 demographically matched healthy controls, served as input features for the classification procedure.
RESULTS: The classifier achieved 72% accuracy (p ≤ 0.001). This discrimination was based on regions that included the left superior temporal gyrus, the right middle temporal gyrus, the left supramarginal gyrus and the superior parietal lobule.
CONCLUSIONS: These results indicate that OCD-related abnormalities in temporal and parietal lobe activation have predictive power for group membership; furthermore, the findings suggest that machine learning techniques can be used to aid in the identification of individuals with OCD in clinical diagnosis.

PMID: 31277632 [PubMed - in process]

Alterations of default mode functional connectivity in individuals with end-stage renal disease and mild cognitive impairment.

Sun, 07/07/2019 - 18:19
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Alterations of default mode functional connectivity in individuals with end-stage renal disease and mild cognitive impairment.

BMC Nephrol. 2019 Jul 05;20(1):246

Authors: Lu H, Gu Z, Xing W, Han S, Wu J, Zhou H, Ding J, Zhang J

Abstract
BACKGROUND: Mild cognitive impairment (MCI) occurs frequently in many end stage renal disease (ESRD) patients, may significantly worsen survival odds and prognosis. However, the exact neuropathological mechanisms of MCI combined with ESRD are not fully clear. This study examined functional connectivity (FC) alterations of the default-mode network (DMN) in individuals with ESRD and MCI.
METHODS: Twenty-four individuals with ESRD identified as MCI patients were included in this study; of these, 19 and 5 underwent hemodialysis (HD) and peritoneal dialysis (PD), respectively. Another group of 25 age-, sex- and education level-matched subjects were recruited as the control group. All participants underwent resting-state functional MRI and neuropsychological tests; the ESRD group underwent additional laboratory testing. Independent component analysis (ICA) was used for DMN characterization. With functional connectivity maps of the DMN derived individually, group comparison was performed with voxel-wise independent samples t-test, and connectivity changes were correlated with neuropsychological and clinical variables.
RESULTS: Compared with the control group, significantly decreased functional connectivity of the DMN was observed in the posterior cingulate cortex (PCC) and precuneus (Pcu), as well as in the medial prefrontal cortex (MPFC) in the ESRD group. Functional connectivity reductions in the MPFC and PCC/Pcu were positively correlated with hemoglobin levels. In addition, functional connectivity reduction in the MPFC showed positive correlation with Montreal Cognitive Assessment (MoCA) score.
CONCLUSION: Decreased functional connectivity in the DMN may be associated with neuropathological mechanisms involved in ESRD and MCI.

PMID: 31277581 [PubMed - in process]

Exploring the functional connectome in white matter.

Sat, 07/06/2019 - 18:18

Exploring the functional connectome in white matter.

Hum Brain Mapp. 2019 Jul 05;:

Authors: Li J, Biswal BB, Wang P, Duan X, Cui Q, Chen H, Liao W

Abstract
A major challenge in neuroscience is understanding how brain function emerges from the connectome. Most current methods have focused on quantifying functional connectomes in gray-matter (GM) signals obtained from functional magnetic resonance imaging (fMRI), while signals from white-matter (WM) have generally been excluded as noise. In this study, we derived a functional connectome from WM resting-state blood-oxygen-level-dependent (BOLD)-fMRI signals from a large cohort (n = 488). The WM functional connectome exhibited weak small-world topology and nonrandom modularity. We also found a long-term (i.e., over 10 months) topological reliability, with topological reproducibility within different brain parcellation strategies, spatial distance effect, global and cerebrospinal fluid signals regression or not. Furthermore, the small-worldness was positively correlated with individuals' intelligence values (r = .17, pcorrected = .0009). The current findings offer initial evidence using WM connectome and present additional measures by which to uncover WM functional information in both healthy individuals and in cases of clinical disease.

PMID: 31276262 [PubMed - as supplied by publisher]

Altered Whole-Brain Functional Topological Organization and Cognitive Function in Type 2 Diabetes Mellitus Patients.

Sat, 07/06/2019 - 18:18

Altered Whole-Brain Functional Topological Organization and Cognitive Function in Type 2 Diabetes Mellitus Patients.

Front Neurol. 2019;10:599

Authors: Qin C, Liang Y, Tan X, Leng X, Lin H, Zeng H, Zhang C, Yang J, Li Y, Zheng Y, Qiu S

Abstract
Type 2 diabetes mellitus (T2DM) is associated with cognitive dysfunction and may even progress to dementia. However, the underlying mechanism of altered functional topological organization and cognitive impairments remains unclear. This study explored the topological properties of functional whole brain networks in T2DM patients with graph theoretical analysis using a resting-state functional magnetic resonance imaging (rs-fMRI) technique. Thirty T2DM patients (aged 51.77 ± 1.42 years) and 30 sex-, age-, and education-matched healthy controls (HCs) (aged 48.87 ± 0.98 years) underwent resting-state functional imaging in a 3.0 T MR scanner in addition to detailed neuropsychological and laboratory tests. Then, graph theoretical network analysis was performed to explore the global and nodal topological alterations in the functional whole brain networks of the T2DM patients. Finally, correlation analyses were performed to investigate the relationship between the altered topological parameters, cognitive performances and clinical variables. Compared to HCs, we found that T2DM patients displayed worse performances in general cognitive function and several cognitive domains, including episodic memory, attention and executive function. In addition, T2DM patients showed a higher small-worldness (σ), a higher normalized clustering coefficient (γ) and a higher local efficiency (Eloc). Moreover, decreased nodal topological properties were mainly distributed in the occipital lobes, frontal lobes, left median cingulate and paracingulate gyri, and left amygdala, while increased nodal topological properties were mainly distributed in the right gyrus rectus, right anterior cingulate and paracingulate gyri, right posterior cingulate gyrus, bilateral caudate nucleus, bilateral cerebellum 3, bilateral cerebellum crus 1, vermis (1, 2) and vermis 3. Some disrupted nodal topological properties were correlated with cognitive performance and HbA1c levels in T2DM patients. This study shows altered functional topological organization in T2DM patients, mainly suggesting a compensation mechanism of the functional whole brain network in the relatively early stage to counteract cognitive impairments.

PMID: 31275222 [PubMed]

A Role for the Claustrum in Salience Processing?

Sat, 07/06/2019 - 18:18

A Role for the Claustrum in Salience Processing?

Front Neuroanat. 2019;13:64

Authors: Smith JB, Watson GDR, Liang Z, Liu Y, Zhang N, Alloway KD

Abstract
The claustrum (CLA) is a subcortical structure, present only in mammals, whose function remains uncertain. Previously, using resting-state functional magnetic resonance imaging (rs-fMRI) in awake head-fixed rats, we found evidence that the CLA is part of the rodent homolog of the default mode network (DMN; Smith et al., 2017). This network emerged as strong functional connections between the medial prefrontal cortex (mPFC), mediodorsal (MD) thalamus, and CLA in the awake state, which was not present following administration of isoflurane anesthesia. In the present report, we review evidence indicating that the rodent CLA also has connections with structures identified in the rodent homolog of the salience network (SN), a circuit that directs attention towards the most relevant stimuli among a multitude of sensory inputs (Seeley et al., 2007; Menon and Uddin, 2010). In humans, this circuit consists of functional connections between the anterior cingulate cortex (ACC) and a region that encompasses both the CLA and insular cortex. We further go on to review the similarities and differences between the functional and anatomical connections of the CLA and insula in rodents using both rs-fMRI and neuroanatomical tracing, respectively. We analyze in detail the connectivity of the CLA with the cingulate cortex, which is a major node in the SN and has been shown to modulate attention. When considered with other recent behavior and physiology studies, the data reveal a role for the CLA in salience-guided orienting. More specifically, we hypothesize that limbic information from mPFC, MD thalamus, and the basolateral amygdala (BLA) are integrated by the CLA to guide modality-related regions of motor and sensory cortex in directing attention towards relevant (i.e., salient) sensory events.

PMID: 31275119 [PubMed]