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[Changes in regional homogeneity of brain activity in patients with diabetic peripheral].

Tue, 01/08/2019 - 21:35
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[Changes in regional homogeneity of brain activity in patients with diabetic peripheral].

Nan Fang Yi Ke Da Xue Xue Bao. 2018 Dec 30;38(12):1433-1439

Authors: Qiu L, Tan X, Zou M, Lao B, Xu Y, Xue Y, Gao F, Cao Y

Abstract
OBJECTIVE: To investigate the abnormalities in regional homogeneity of brain activity in patients with diabetic peripheral neuropathy (DPN) using resting-state functional magnetic resonance imaging (rs-fMRI) and explore the association between brain activity changes and DPN.
METHODS: A regional homogeneity (ReHo) approach was used to compare the local synchronization of rs-fMRI signals among 20 patients with painful DPN, 16 patients with painless DPN, and 16 type 2 diabetic patients without DPN (non-DPN group).
RESULTS: Compared with the those without DPN, the patients with painful DPN showed high ReHo in the left inferior temporal gyrus and the right central posterior gyrus, and low ReHo in the posterior cingulate gyrus, right inferior parietal gyrus, and the left superior parietal gyrus (P < 0.05);the patients with painless DPN group showed high ReHo in the left inferior temporal gyrus, the right middle temporal gyrus, and the right superior frontal gyrus, and low ReHo in the left thalamus (P < 0.05).No significant differences in ReHo were found between the patients with painful DPN and painless DPN (P>0.05).
CONCLUSIONS: The patients with DPN have altered ReHo in multiple brain regions and impairment of a default mode network, for which the left temporal gyrus may serve as a functional compensatory brain area. ReHo disturbance in the central right posterior gyrus may play a central role in the pain symptoms associated with painful DPN.

PMID: 30613010 [PubMed - in process]

Common Dysfunction of Large-Scale Neurocognitive Networks Across Psychiatric Disorders.

Tue, 01/08/2019 - 21:35
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Common Dysfunction of Large-Scale Neurocognitive Networks Across Psychiatric Disorders.

Biol Psychiatry. 2018 Nov 23;:

Authors: Sha Z, Wager TD, Mechelli A, He Y

Abstract
BACKGROUND: Cognitive dysfunction is one of the most prominent characteristics of psychiatric disorders. Currently, the neural correlates of cognitive dysfunction across psychiatric disorders are poorly understood. The aim of this study was to investigate functional connectivity and structural perturbations across psychiatric diagnoses in three neurocognitive networks of interest: the default mode network (DMN), the frontoparietal network (FPN), and the salience network (SN).
METHODS: We performed meta-analyses of resting-state functional magnetic resonance imaging whole-brain seed-based functional connectivity in 8298 patients (involving eight disorders) and 8165 healthy control subjects and a voxel-based morphometry analysis of structural magnetic resonance imaging data in 14,027 patients (involving eight disorders) and 14,504 healthy control subjects. To aid the interpretation of the results, we examined neurocognitive function in 776 healthy participants from the Human Connectome Project.
RESULTS: We found that the three neurocognitive networks of interest were characterized by shared alterations of functional connectivity architecture across psychiatric disorders. More specifically, hypoconnectivity was expressed between the DMN and ventral SN and between the SN and FPN, whereas hyperconnectivity was evident between the DMN and FPN and between the DMN and dorsal SN. This pattern of network alterations was associated with gray matter reductions in patients and was localized in regions that subserve general cognitive performance.
CONCLUSIONS: This study is the first to provide meta-analytic evidence of common alterations of functional connectivity within and between neurocognitive networks. The findings suggest a shared mechanism of network interactions that may associate with the generalized cognitive deficits observed in psychiatric disorders.

PMID: 30612699 [PubMed - as supplied by publisher]

Aberrant cerebellar neural activity and cerebro-cerebellar functional connectivity involving executive dysfunction in schizophrenia with primary negative symptoms.

Tue, 01/08/2019 - 03:34
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Aberrant cerebellar neural activity and cerebro-cerebellar functional connectivity involving executive dysfunction in schizophrenia with primary negative symptoms.

Brain Imaging Behav. 2019 Jan 05;:

Authors: Gao J, Tang X, Wang C, Yu M, Sha W, Wang X, Zhang H, Zhang X, Zhang X

Abstract
Deficit schizophrenia (DS) is a distinct subtype of schizophrenia characterized by primary and enduring negative symptoms. More severe executive dysfunctions were observed in DS patients, however, the associated neuroimaging characteristics, especially cerebellar functional anomalies in DS, remain largely unknown. We employed resting-state functional and structural MRI data of 106 male participants, including data from 29 DS patients, 39 non-deficit schizophrenia (NDS) patients and 38 healthy controls (HCs). Z-standardized fractional amplitude of low-frequency fluctuation (zfALFF) values were calculated in order to examine spontaneous regional brain activity. Cerebro-cerebellar functional connectivity and changes in the volume of gray matter in the cerebellum were also examined. Relative to the HCs, both DS and NDS patients exhibited decreased zfALFF in the bilateral cerebellar lobules VIII and IX. The zfALFF in the left Crus II was lower in DS patients compared to NDS patients. No significant difference was observed in the volume of cerebellar gray matter among the three groups. Compared with NDS patients, cerebro-cerebellar functional connectivity analysis revealed increased connectivity in the left orbital medial frontal cortex and right putamen regions in DS patients. Reduced zfALFF in the left Crus II in the DS group was significantly positively correlated with Stroop Color and Word scores, while negatively correlated with Trail-Making Test part B scores. The increased functional connectivity in the right putamen in DS patients was significantly positively correlated with Animal Naming Test and semantic Verbal Fluency Test scores. These results highlight cerebellar functional abnormality in DS patients and provide insight into the pathophysiological mechanism of executive dysfunction.

PMID: 30612342 [PubMed - as supplied by publisher]

Changed hub and functional connectivity patterns of the posterior fusiform gyrus in chess experts.

Tue, 01/08/2019 - 03:34
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Changed hub and functional connectivity patterns of the posterior fusiform gyrus in chess experts.

Brain Imaging Behav. 2019 Jan 05;:

Authors: Song L, Peng Q, Liu S, Wang J

Abstract
The hubs of the brain network play a key role in integrating and transferring information between different functional modules. However, the effects of long-term practice on functional network hubs in chess experts are largely undefined. Here, we investigated whether alterations of hubs can be detected in chess experts using resting-state functional magnetic resonance imaging (rs-fMRI) and graph theory methods. We first mapped the whole-brain voxel-wise functional connectivity and calculated the functional connectivity strength (FCS) map in each of the 28 chess players and 27 gender- and age-matched healthy novice players. Whole-brain resting-state functional connectivity analyses for the changed hub areas were conducted to further elucidate the corresponding changes of functional connectivity patterns in chess players. The hub analysis revealed increased FCS in the right posterior fusiform gyrus of the chess players, which was supported by analyses of this area's regional homogeneity (ReHo), amplitude of low frequency fluctuations (ALFF), and fractional amplitude of low frequency fluctuations (fALFF). The following functional connectivity analyses revealed increased functional connectivities between the right posterior fusiform gyrus and the visuospatial attention and motor networks in chess players. These findings demonstrate that cognitive expertise has a positive influence on the functions of the brain regions associated with the chess expertise and that increased functional connections might in turn facilitate within and between networks communication for expert behavior to get superior performance.

PMID: 30612341 [PubMed - as supplied by publisher]

Awake and behaving mouse fMRI during Go/No-Go task.

Tue, 01/08/2019 - 03:34
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Awake and behaving mouse fMRI during Go/No-Go task.

Neuroimage. 2019 Jan 03;:

Authors: Han Z, Chen W, Chen X, Zhang K, Tong C, Zhang X, Li CT, Liang Z

Abstract
Functional magnetic imaging (fMRI) has been widely used to examine the functional neural networks in both the evoked and resting states. However, most fMRI studies in rodents are performed under anesthesia, which greatly limits the scope of their application, and behavioral relevance. Efforts have been made to image rodents in the awake condition, either in the resting state or in response to sensory or optogenetic stimulation. However, fMRI in awake behaving rodents has not yet been achieved. In the current study, a novel fMRI paradigm for awake and behaving mice was developed, allowing functional imaging of the mouse brain in an olfaction-based go/no-go task. High resolution functional imaging with limited motion and image distortion were achieved at 9.4T with a cryogenic coil in awake and behaving mice. Distributed whole-brain spatiotemporal patterns were revealed, with drastically different activity profiles for go versus no-go trials. Therefore, we have demonstrated the feasibility of functional imaging of an olfactory behavior in awake mice. This fMRI paradigm in awake behaving mice could lead to novel insights into neural mechanisms underlying behaviors at a whole-brain level.

PMID: 30611875 [PubMed - as supplied by publisher]

Early childhood network alterations in severe autism.

Mon, 01/07/2019 - 11:24
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Early childhood network alterations in severe autism.

Asian J Psychiatr. 2018 Dec 21;39:114-119

Authors: Kaku SM, Jayashankar A, Girimaji SC, Bansal S, Gohel S, Bharath RD, Srinath S

Abstract
OBJECTIVE: To examine the differences in whole brain topology and connectivity in 17 children of the ages 3-8 years across severity of ASD, we performed resting state fMRI using a 3T MRI scanner and graph theoretical analysis of networks.
METHOD: Patients were partitioned into two cohorts based on the severity of ASD, determined using the Childhood Autism Rating Scale (CARS) scores (Mild, 30-36; Severe, 37+). Standard preprocessing pipeline was used, followed by independent component analysis (ICA) to identify regions of interest (ROIs) to construct subject-specific Z-correlation matrices representing the whole brain network. Following which, graph theory measures were calculated in the range of sparsity 6%-35% and statistically analyzed, and corrected for significance (FDR corrected, p < 0.05). Regional clustering coefficient that revealed significant between-group (mild vs. severe) differences were correlated against clinical scores (CARS).
RESULTS: Children with severe ASD revealed significantly increased clustering coefficient and small-worldness compared to those with mild or moderate ASD. Region of interest analysis revealed altered clustering in the Heschl's gyrus that significantly correlated with CARS scores.
CONCLUSION: The findings from the current study provide early stage evidence of aberrant brain connectivity appearing in severe ASD, prior to the effect of environmental bias and pruning mechanisms. The clustering of the Heschl's gyrus correlated to the severity of ASD symptoms and agrees with current literature on ASD-associated cortical changes, reflecting early changes to language processing regions.

PMID: 30610990 [PubMed - as supplied by publisher]

Diagnostic and prognostic biomarkers for HAND.

Sun, 01/06/2019 - 14:49
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Diagnostic and prognostic biomarkers for HAND.

J Neurovirol. 2019 Jan 03;:

Authors: McLaurin KA, Booze RM, Mactutus CF

Abstract
In 2007, the nosology for HIV-1-associated neurocognitive disorders (HAND) was updated to a primarily neurocognitive disorder. However, currently available diagnostic tools lack the sensitivity and specificity needed for an accurate diagnosis for HAND. Scientists and clinicians, therefore, have been on a quest for an innovative biomarker to diagnose (i.e., diagnostic biomarker) and/or predict (i.e., prognostic biomarker) the progression of HAND in the post-combination antiretroviral therapy (cART) era. The present review examined the utility and challenges of four proposed biomarkers, including neurofilament light (NFL) chain concentration, amyloid (i.e., sAPPα, sAPPβ, amyloid β) and tau proteins (i.e., total tau, phosphorylated tau), resting-state functional magnetic resonance imaging (fMRI), and prepulse inhibition (PPI). Although significant genotypic differences have been observed in NFL chain concentration, sAPPα, sAPPβ, amyloid β, total tau, phosphorylated tau, and resting-state fMRI, inconsistencies and/or assessment limitations (e.g., invasive procedures, lack of disease specificity, cost) challenge their utility as a diagnostic and/or prognostic biomarker for milder forms of neurocognitive impairment (NCI) in the post-cART era. However, critical evaluation of the literature supports the utility of PPI as a powerful diagnostic biomarker with high accuracy (i.e., 86.7-97.1%), sensitivity (i.e., 89.3-100%), and specificity (i.e., 79.5-94.1%). Additionally, the inclusion of multiple CSF and/or plasma markers, rather than a single protein, may provide a more sensitive diagnostic biomarker for HAND; however, a pressing need for additional research remains. Most notably, PPI may serve as a prognostic biomarker for milder forms of NCI, evidenced by its ability to predict later NCI in higher-order cognitive domains with regression coefficients (i.e., r) greater than 0.8. Thus, PPI heralds an opportunity for the development of a brief, noninvasive diagnostic and promising prognostic biomarker for milder forms of NCI in the post-cART era.

PMID: 30607890 [PubMed - as supplied by publisher]

Modulation of anterior cingulate cortex reward and penalty signalling in medication-naive young-adult subjects with depressive symptoms following acute dose lurasidone.

Sun, 01/06/2019 - 14:49
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Modulation of anterior cingulate cortex reward and penalty signalling in medication-naive young-adult subjects with depressive symptoms following acute dose lurasidone.

Psychol Med. 2019 Jan 04;:1-13

Authors: Wolke SA, Mehta MA, O'Daly O, Zelaya F, Zahreddine N, Keren H, O'Callaghan G, Young A, Leibenluft E, Pine DS, Stringaris A

Abstract
BACKGROUND: Aberrations in reward and penalty processing are implicated in depression and putatively reflect altered dopamine signalling. This study exploits the advantages of a placebo-controlled design to examine how a novel D2 antagonist with adjunctive antidepressant properties modifies activity in the brain's reward network in depression.
METHODS: We recruited 43 medication-naïve subjects across the range of depression severity (Beck's Depression Inventory-II score range: 0-43), including healthy volunteers, as well as people meeting full-criteria for major depressive disorder. In a double-blind placebo-controlled cross-over design, all subjects received either placebo or lurasidone (20 mg) across two visits separated by 1 week. Functional magnetic resonance imaging with the Monetary Incentive Delay (MID) task assessed reward functions via neural responses during anticipation and receipt of gains and losses. Arterial spin labelling measured cerebral blood flow (CBF) at rest.
RESULTS: Lurasidone altered fronto-striatal activity during anticipation and outcome phases of the MID task. A significant three-way Medication-by-Depression severity-by-Outcome interaction emerged in the anterior cingulate cortex (ACC) after correction for multiple comparisons. Follow-up analyses revealed significantly higher ACC activation to losses in high- v. low depression participants in the placebo condition, with a normalisation by lurasidone. This effect could not be accounted for by shifts in resting CBF.
CONCLUSIONS: Lurasidone acutely normalises reward processing signals in individuals with depressive symptoms. Lurasidone's antidepressant effects may arise from reducing responses to penalty outcomes in individuals with depressive symptoms.

PMID: 30606271 [PubMed - as supplied by publisher]

Precuneus and psychiatric manifestations: Novel neurobiological formulations through lesion based connectivity mapping of psychopathology.

Wed, 01/02/2019 - 23:49
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Precuneus and psychiatric manifestations: Novel neurobiological formulations through lesion based connectivity mapping of psychopathology.

Asian J Psychiatr. 2018 Dec 27;39:98-100

Authors: Narasimha VL, Basavaraju R, Mangalore S, Mehta UM

Abstract
Lesion-based investigations of psychopathology have preceded contemporary network-neuroscience initiatives. However, brain-lesions detected in routine psychiatric practice are often considered incidental and therefore ignored. Here, we illustrate a strategy to combine individual subject-level lesion information with open-source normative functional-connectomics data to make putative, neuroscience-informed symptom interpretation. Specifically, we report a patient with left precuneus granulomatous lesion and seizures followed by two distinct symptoms - kinetopsia and delusions of nihilism and guilt - which had a differential treatment response. The lesion-based brain-mapping approach could identify correlated (default-mode) and anti-correlated (temporo-parieto-occipital) networks, which enabled a neurobiological formulation of these diverse clinical manifestations.

PMID: 30599452 [PubMed - as supplied by publisher]

Altered regional homogeneity in patients with somatic depression: A resting-state fMRI study.

Wed, 01/02/2019 - 23:49
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Altered regional homogeneity in patients with somatic depression: A resting-state fMRI study.

J Affect Disord. 2018 Dec 26;246:498-505

Authors: Geng J, Yan R, Shi J, Chen Y, Mo Z, Shao J, Wang X, Lu Q, Yao Z

Abstract
BACKGROUND: Somatic symptoms are common among patients with major depressive disorder (MDD), and are known to negatively impact the course and severity of the disease. Although previous studies have attempted to explore the neuropathology of MDD, little is known regarding the neural basis of somatic symptoms in MDD.
METHODS: Resting-state functional magnetic resonance images of 28 MDD patients with somatic symptoms (somatic depression, SD), 30 patients without somatic symptoms (non-somatic depression, NSD) and 30 healthy controls (HC) were obtained. We investigated the neural basis of MDD with somatic symptoms based on the measure of regional homogeneity (ReHo). We also investigated whether the altered regional homogeneity may be correlated to any clinical features of depression. These comparison were also carried out in female and male subjects respectively.
RESULTS: The SD exhibited higher ReHo in the bilateral parahippocampus and left lingual gyrus than HC, as well as lower ReHo in the right frontal gyrus. Relative to NSD, the SD exhibited lower ReHo in the right middle frontal gyrus and left precentral gyrus. Furthermore, in the SD, ReHo in the left precentral gyrus was positively correlated with cognitive factor scores of the HAMD-17. In female subjects, SD exhibited increased ReHo in the right STG and decreased ReHo in the right MFG, relative to women of the NSD group.
CONCLUSIONS: Our preliminary findings indicated that abnormal ReHo in the frontal and temporal regions may play an important role in the neural basis of somatic depression.

PMID: 30599374 [PubMed - as supplied by publisher]

Enhanced central neural gain compensates acoustic trauma-induced cochlear impairment, but unlikely correlates with tinnitus and hyperacusis.

Wed, 01/02/2019 - 23:49
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Enhanced central neural gain compensates acoustic trauma-induced cochlear impairment, but unlikely correlates with tinnitus and hyperacusis.

Neuroscience. 2018 Dec 29;:

Authors: Möhrle D, Hofmeier B, Amend M, Wolpert S, Ni K, Bing D, Klose U, Pichler B, Knipper M, Rüttiger L

Abstract
For successful future therapeutic strategies for tinnitus and hyperacusis, a subcategorization of both conditions on the basis of differentiated neural correlates would be of invaluable advantage. In the present study, we used our refined operant conditioning animal model to divide equally noise-exposed rats into groups with either tinnitus or hyperacusis, with neither condition, or with both conditions co-occurring simultaneously. Using click stimulus and noise burst-evoked Auditory Brainstem Responses (ABR) and Distortion Product Otoacoustic Emissions, no hearing threshold difference was observed between any of the groups. However, animals with neither tinnitus nor hyperacusis responded to noise trauma with shortened ABR wave I and IV latencies and elevated central neuronal gain (increased ABR wave IV/I amplitude ratio), which was previously assumed in most of the literature to be a neural correlate for tinnitus. In contrast, animals with tinnitus had reduced neural response gain and delayed ABR wave I and IV latencies, while animals with hyperacusis showed none of these changes. Preliminary studies, aimed at establishing comparable non-invasive objective tools for identifying tinnitus in humans and animals, confirmed reduced central gain and delayed response latency in human and animals. Moreover, the first ever resting state functional Magnetic Resonance Imaging (rs-fMRI) analyses comparing humans and rats with and without tinnitus showed reduced rs-fMRI activities in the auditory cortex in both patients and animals with tinnitus. These findings encourage further efforts to establish non-invasive diagnostic tools that can be used in humans and animals alike and give hope for differentiated classification of tinnitus and hyperacusis.

PMID: 30599268 [PubMed - as supplied by publisher]

Alterations of the default mode network and cognitive impairment in patients with unilateral chronic tinnitus.

Wed, 01/02/2019 - 23:49
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Alterations of the default mode network and cognitive impairment in patients with unilateral chronic tinnitus.

Quant Imaging Med Surg. 2018 Nov;8(10):1020-1029

Authors: Chen YC, Zhang H, Kong Y, Lv H, Cai Y, Chen H, Feng Y, Yin X

Abstract
Background: Previous studies have demonstrated that cognitive impairment is linked with neurophysiological alterations in chronic tinnitus. This study aimed to investigate the intrinsic functional connectivity (FC) pattern within the default mode network (DMN) and its associations with cognitive impairment in tinnitus patients using a resting-state functional magnetic resonance imaging (rs-fMRI).
Methods: Thirty-five chronic unilateral tinnitus patients, and 50 healthy controls were recruited for rsfMRI scanning. Both groups were age, gender and education level well-matched. The posterior cingulate cortex (PCC) was chosen as the region of interest (ROI) for detecting the FC changes, and determining if these abnormalities were related to a specific cognitive performance and tinnitus characteristic.
Results: Relative to the healthy controls, tinnitus patients showed increased FC between the PCC and the right medial prefrontal cortex (mPFC). Moreover, the enhanced FC between the PCC and right mPFC was correlated with the poorer TMT-B scores (r=0.474, P=0.008). These correlations were adjusted by age, gender, education level, GM volume, and mean hearing thresholds. The enhanced FC was not correlated with other tinnitus characteristics or cognitive performances.
Conclusions: The enhanced FC pattern of the PCC that is correlated with cognitive impairment in chronic tinnitus patients, especially the executive dysfunction. Enhanced connectivity pattern within the DMN may play a crucial role in neurophysiological mechanism in tinnitus patients with cognitive dysfunction.

PMID: 30598879 [PubMed]

Spatial complexity of brain signal is altered in patients with generalized anxiety disorder.

Tue, 01/01/2019 - 19:46

Spatial complexity of brain signal is altered in patients with generalized anxiety disorder.

J Affect Disord. 2018 Dec 26;246:387-393

Authors: Wang Y, Wang X, Ye L, Yang Q, Cui Q, He Z, Li L, Yang X, Zou Q, Yang P, Liu D, Chen H

Abstract
BACKGROUND: Is it healthy to be chaotic? Recent studies have argued that mental disorders are associated with more orderly neural activities, corresponding to a less flexible functional system. These conclusions were derived from altered temporal complexity. However, the relationship between spatial complexity and health is unknown, although spatial configuration is of importance for normal brain function.
METHODS: Based on resting-state functional magnetic resonance imaging data, we used Sample entropy (SampEn) to evaluate the altered spatial complexity in patients with generalized anxiety disorder (GAD; n = 47) compared to healthy controls (HCs; n = 38) and the relationship between spatial complexity and anxiety level.
RESULTS: Converging results showed increased spatial complexity in patients with GAD, indicating more chaotic spatial configuration. Interestingly, inverted-U relationship was revealed between spatial complexity and anxiety level, suggesting complex relationship between health and the chaos of human brain.
LIMITATIONS: Anxiety-related alteration of spatial complexity should be verified at voxel level in a larger sample and compared with results of other indices to clarify the mechanism of spatial chaotic of anxiety.
CONCLUSIONS: Altered spatial complexity in the brain of GAD patients mirrors inverted-U relationship between anxiety and behavioral performance, which may reflect an important characteristic of anxiety. These results indicate that SampEn is a good reflection of human health or trait mental characteristic.

PMID: 30597300 [PubMed - as supplied by publisher]

Dynamic functional abnormalities in generalized anxiety disorders and their increased network segregation of a hyperarousal brain state modulated by insomnia.

Tue, 01/01/2019 - 19:46

Dynamic functional abnormalities in generalized anxiety disorders and their increased network segregation of a hyperarousal brain state modulated by insomnia.

J Affect Disord. 2018 Dec 25;246:338-345

Authors: Li C, Xia L, Ma J, Li S, Liang S, Ma X, Wang T, Li M, Wen H, Jiang G

Abstract
BACKGROUND: Insomnia is frequently accompanied by the generalized anxiety disorder (GAD) but mostly fMRI studies investigated their aberrant functional connectivity (FC) without this issue. Recently, dynamic FC approach is prevailing to capture the time-varying fluctuations of spontaneous brain activities. Nevertheless, it is unclear how the dynamic FC characteristics are altered by insomnia in GAD.
METHODS: We acquired resting state fMRI and neuropsychological tests for the 17 comorbid GAD with insomnia (GAD/IS), 15 GAD and 24 healthy controls (HC). Then, based on the sliding window correlations, we estimated distinct brain states and statistically compared their dynamic properties. Further combining with graph theory, their network properties of each state among groups were accessed. Lastly, we examined associations between abnormal parameters and neuropsychological tests.
RESULTS: We identified four brain states but did not observe significance on the state transitions. The mean dwell time and fraction of one globally hypoactive state accounted for high proportion of brain activities were significantly different (GAD > HC > GAD/IS). Meanwhile, we found gradual decreases in a brain state representing slight sleep/drowsiness (HC > GAD/IS > GAD). Additionally, we observed the GAD/IS patients had significantly increased network segregation and posterior cingulate cortex in a hyperarousal state, as well as significant associations with anxiety and insomnia severity.
LIMITATIONS: The influences of depression on dynamic FC properties in GAD are unclear yet and more subjects should be recruited.
CONCLUSIONS: These results provide new insights about the temporal features in GAD and offer potential biomarkers to evaluate the impacts of insomnia.

PMID: 30597294 [PubMed - as supplied by publisher]

A Single Session of Robot-Controlled Proprioceptive Training Modulates Functional Connectivity of Sensory Motor Networks and Improves Reaching Accuracy in Chronic Stroke.

Tue, 01/01/2019 - 19:46
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A Single Session of Robot-Controlled Proprioceptive Training Modulates Functional Connectivity of Sensory Motor Networks and Improves Reaching Accuracy in Chronic Stroke.

Neurorehabil Neural Repair. 2018 Dec 29;:1545968318818902

Authors: Vahdat S, Darainy M, Thiel A, Ostry DJ

Abstract
BACKGROUND: Passive robot-generated arm movements in conjunction with proprioceptive decision making and feedback modulate functional connectivity (FC) in sensory motor networks and improve sensorimotor adaptation in normal individuals. This proof-of-principle study investigates whether these effects can be observed in stroke patients.
METHODS: A total of 10 chronic stroke patients with a range of stable motor and sensory deficits (Fugl-Meyer Arm score [FMA] 0-65, Nottingham Sensory Assessment [NSA] 10-40) underwent resting-state functional magnetic resonance imaging before and after a single session of robot-controlled proprioceptive training with feedback. Changes in FC were identified in each patient using independent component analysis as well as a seed region-based approach. FC changes were related to impairment and changes in task performance were assessed.
RESULTS: A single training session improved average arm reaching accuracy in 6 and proprioception in 8 patients. Two networks showing training-associated FC change were identified. Network C1 was present in all patients and network C2 only in patients with FM scores >7. Relatively larger C1 volume in the ipsilesional hemisphere was associated with less impairment ( r = 0.83 for NSA, r = 0.73 for FMA). This association was driven by specific regions in the contralesional hemisphere and their functional connections (supramarginal gyrus with FM scores r = 0.82, S1 with NSA scores r = 0.70, and cerebellum with NSA score r = -0.82).
CONCLUSION: A single session of robot-controlled proprioceptive training with feedback improved movement accuracy and induced FC changes in sensory motor networks of chronic stroke patients. FC changes are related to functional impairment and comprise bilateral sensory and motor network nodes.

PMID: 30595082 [PubMed - as supplied by publisher]

Hypoconnectivity of insular resting-state networks in adolescents with Autism Spectrum Disorder.

Tue, 01/01/2019 - 12:56
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Hypoconnectivity of insular resting-state networks in adolescents with Autism Spectrum Disorder.

Psychiatry Res Neuroimaging. 2018 Dec 07;283:104-112

Authors: Francis SM, Camchong J, Brickman L, Goelkel-Garcia L, Mueller BA, Tseng A, Lim KO, Jacob S

Abstract
Autism Spectrum Disorder (ASD) is characterized by deficits in social interaction and communication. The anterior insula (AI) participates in emotional salience detection; and the posterior insula (PI) participates in sensorimotor integration and response selection. Meta-analyses have noted insula-based aberrant connectivity within ASD. Given the observed social impairments in ASD and the role of the insula in social information processing (SIP), investigating functional organization of this structure in ASD is important. We investigated differences in resting-state functional connectivity (RSFC) using fMRI in male youths with (N=13; mean=14.6 years; range: 10.2-18.0 years) and without ASD (N=17; mean=14.5 years; range: 10.0-17.5 years). With seed-based FC measures, we compared RSFC in insular networks. Hypoconnectivity was observed in ASD (AI-superior frontal gyrus (SFG); AI-thalamus; PI-inferior parietal lobule (IPL); PI-fusiform gyrus (FG); PI-lentiform nucleus/putamen). Using the Social Communication Questionnaire (SCQ) to assess social functioning, regression analyses yielded negative correlations between SCQ scores and RSFC (AI-SFG; AI-thalamus; PI-FG; PI-IPL). Given the insula's connections to limbic regions, and its role in integrating external sensory stimuli with internal states, atypical activity in this structure may be associated with social deficits characterizing ASD. Our results suggest further investigation of the insula's role in SIP across a continuum of social abilities is needed.

PMID: 30594068 [PubMed - as supplied by publisher]

Brain network functional connectivity and cognitive performance in major depressive disorder.

Tue, 01/01/2019 - 12:56
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Brain network functional connectivity and cognitive performance in major depressive disorder.

J Psychiatr Res. 2018 Nov 22;110:51-56

Authors: Albert KM, Potter GG, Boyd BD, Kang H, Taylor WD

Abstract
BACKGROUND: Major depressive disorder (MDD) is one of the most prevalent and debilitating psychiatric disorders. Cognitive complaints are commonly reported in MDD and cognitive impairment is a criterion item for MDD diagnosis. As cognitive processes are increasingly understood as the consequences of distributed interactions between brain regions, a network-based approach may provide novel information about the neurobiological basis of cognitive deficits in MDD.
METHODS: 51 Depressed (MDD, n = 23) and non-depressed (control, n = 28) adult participants completed neuropsychological testing and resting-state fMRI (rsfMRI). Cognitive domain scores (processing speed, working memory, episodic memory, and executive function) were calculated. Anatomical regions of interests were entered as seeds for functional connectivity analyses in: default mode (DMN), salience, and executive control (ECN) networks. Partial correlations controlling for age and sex were conducted for cognitive domain scores and functional connectivity in clusters with significant differences between groups.
RESULTS: Significant rsfMRI differences between groups were identified in multiple clusters in the DMN and ECN. Greater positive connectivity within the ECN and between ECN and DMN regions was associated with poorer episodic memory performance in the Non-Depressed group but better performance in the MDD group. Greater connectivity within the DMN was associated with better episodic and working memory performance in the Non-Depressed group but worse performance in the MDD group.
CONCLUSIONS: These results provide evidence that cognitive performance in MDD may be associated with aberrant functional connectivity in cognitive networks and suggest patterns of alternate brain function that may support cognitive processes in MDD.

PMID: 30594024 [PubMed - as supplied by publisher]

Evaluation of nuisance removal for functional MRI of rodent brain.

Tue, 01/01/2019 - 12:56
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Evaluation of nuisance removal for functional MRI of rodent brain.

Neuroimage. 2018 Dec 26;:

Authors: Chuang KH, Lee HL, Li Z, Chang WT, Nasrallah FA, Yeow LY, Singh KKDR

Abstract
Functional MRI (fMRI) has become an important translational tool for studying brain activity and connectivity in animal models and humans. For accurate and reliable measurement of functional connectivity, nuisance removal strategies developed for human brain, such as regressing motion parameters, cerebrospinal fluid (CSF)/white matter-derived signals and the global signal, have been applied to rodent. However, due to the very different anatomy, with the majority of the rodent brain being gray matter, and experimental conditions, in which animals are anesthetized and head-fixed, these methods may not be suitable for rodent fMRI. In this study, we assessed various nuisance regression methods and the effects of motion correction on a large dataset of both task and resting fMRI of anesthetized rat brain. Sensitivity and specificity were assessed in the somatosensory pathway under forepaw stimulation and resting state. Reproducibility at various sample sizes was simulated by randomly subsampling the dataset. To overcome the difficulty in extracting nuisance from the brain, a method using principal components estimated from tissues outside the brain was evaluated. Our results showed that neither detrend, motion correction, motion regression nor CSF signal regression could improve specificity despite increasing temporal signal-to-noise ratios. Although global signal regression increased the specificity of task activation and functional connectivity, the sensitivity and connectivity strength was drastically reduced, likely due to its strong correlation with the cortical signal. Motion parameters also correlated with task activation and the global signal, indicating that motion correction detected intensity variations in the brain. The nuisance estimated from tissues outside the brain produced a moderate improvement in specificity. In conclusion, nuisance removal suitable for human fMRI may not be optimal for rodents. While further development is needed, estimating nuisance from tissues outside the brain may be an alternative.

PMID: 30593905 [PubMed - as supplied by publisher]

Sex difference in the effect of Internet gaming disorder on the brain functions: Evidence from resting-state fMRI.

Tue, 01/01/2019 - 12:56
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Sex difference in the effect of Internet gaming disorder on the brain functions: Evidence from resting-state fMRI.

Neurosci Lett. 2018 Dec 26;:

Authors: Wang M, Hu Y, Wang Z, Du X, Dong G

Abstract
OBJECTIVE: Studies have shown that males are more prevalence than females in Internet gaming disorder (IGD). This study was set to explore the sex difference on the effect of IGD in resting states of the brain.
METHODS: Resting-state fMRI data were collected from 58 recreational Internet game users (RGU, male = 29) and 46 IGD subjects (male = 23). Regional homogeneity (ReHo) was used to calculate group difference between the subjects. A two-way ANOVA was used to explore the IGD-by-sex interactions. Correlations between addiction severity and the ReHo values were also calculated.
RESULTS: Significant sex-by-group interactions were found associated with the brain features in the right posterior cingulate (rPCC), left middle occipital gyrus (lMOG), right middle temporal gyrus (rMTG), and right postcentral gyrus (rPG). Post-hoc analysis revealed that comparing with same-sex RGUs, male IGD showed decreased ReHo in the rPCC, and the ReHo in the rPCC was also negatively associated with Internet addiction test (IAT) scores for male subjects. Moreover, male IGDs showed increased ReHo, but female ones showed decreased ReHo, in both lMOG and rMTG, when comparing with same-sex RGUs.
CONCLUSIONS: Sex differences were observed in brain regions that are responsible for executive control, visual and auditory perception. These sex differences should be taken into consideration in future studies and the treatment of IGD.

PMID: 30593873 [PubMed - as supplied by publisher]

A Survey on applications and Analysis Methods of Functional Magnetic Resonance Imaging for Alzheimer's Disease.

Tue, 01/01/2019 - 12:56
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A Survey on applications and Analysis Methods of Functional Magnetic Resonance Imaging for Alzheimer's Disease.

J Neurosci Methods. 2018 Dec 26;:

Authors: Forouzannezhad P, Abbaspour A, Fang C, Cabrerizo M, Loewenstein D, Duara R, Adjouadi M

Abstract
BACKGROUND: Functional magnetic resonance imaging (fMRI) is an MRI-based neuroimaging technique that measures brain activity basis of blood oxygenation level. This study reviews the main fMRI methods reported in the literature and their related applications in clinical and preclinical studies, focusing on relating functional brain networks in the prodromal stages of AD, with a focus on mild cognitive impairment (MCI) to AD.
NEW METHOD: The purpose of this article is to present and compare different approaches of supervised and unsupervised fMRI analyses and to highlight the different applications of fMRI in the diagnosis of MCI and AD.
RESULTS: survey article asserts that brain network disruptions of a given dysfunction or in relation to disease prone areas of the brain in neurodegenerative dementias could be extremely useful in ascertaining the extent of cognitive deficits at the different stages of the disease. Identifying the earliest changes in these activity patterns is essential for the early planning of treatment and therapeutic protocols.
COMPARISON WITH EXISTING METHODS: Analysis methods such as independent component analysis (ICA) and graph theory-based approaches are strong analytical techniques most suitable for functional connectivity investigations. However, graph theory-based approaches have received more attention due to the higher performance they achieve in both functional and effective connectivity studies.
CONCLUSION: This article shows that disruption of brain connectivity patterns of MCI and AD could be associated to the cognitive decline and interesting finding that could augment the prospects for early diagnosis. Multimodal neuroimaging will provide more clinical insight of brain functional and structural mapping.

PMID: 30593787 [PubMed - as supplied by publisher]