New resting-state fMRI related studies at PubMed

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Modifications in resting state functional anticorrelation between default mode network and dorsal attention network: comparison among young adults, healthy elders and mild cognitive impairment patients.

Thu, 02/09/2017 - 12:35
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Modifications in resting state functional anticorrelation between default mode network and dorsal attention network: comparison among young adults, healthy elders and mild cognitive impairment patients.

Brain Imaging Behav. 2017 Feb 07;:

Authors: Esposito R, Cieri F, Chiacchiaretta P, Cera N, Lauriola M, Di Giannantonio M, Tartaro A, Ferretti A

Abstract
Resting state brain activity incorporates different components, including the Default Mode Network and the Dorsal Attention Network, also known as task-negative network and task-positive network respectively. These two networks typically show an anticorrelated activity during both spontaneous oscillations and task execution. However modifications of this anticorrelated activity pattern with age and pathology are still unclear. The present study aimed to investigate differences in resting state Default Mode Network-Dorsal Attention Network functional anticorrelation among young adults, healthy elders and Mild Cognitive Impairment patients. We retrospectively enrolled in this study 27 healthy young adults (age range: 25-35 y.o.; mean age: 28,5), 26 healthy elders (age range: 61-72 y.o.; mean age: 65,1) and 17 MCI patients (age range 64-87 y.o.; mean age: 73,6). Mild Cognitive Impairment patients were selected following Petersen criteria. All participants underwent neuropsychological evaluation and resting state functional Magnetic Resonance Imaging. Spontaneous anticorrelated activity between Default Mode Network and Dorsal Attention Network was observed in each group. This anticorrelation was significantly decreased with age in most Default Mode Network-Dorsal Attention Network connections (p < 0.001, False Discovery Rate corrected). Moreover, the anticorrelation between the posterior cingulate cortex node of the Default Mode Network and the right inferior parietal sulcus node of the Dorsal Attention Network was significantly decreased when comparing Mild Cognitive Impairment with normal elders (p < 0.001, False Discovery Rate corrected). The functional connectivity changes in patients were not related to significant differences in grey matter content. Our results suggest that a reduced anticorrelated activity between Default Mode Network and Dorsal Attention Network is part of the normal aging process and that Mild Cognitive Impairment status is associated with more evident inter-networks functional connectivity changes.

PMID: 28176262 [PubMed - as supplied by publisher]

Resting-State Brain Abnormalities in Chronic Subjective Tinnitus: A Meta-Analysis.

Thu, 02/09/2017 - 12:35
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Resting-State Brain Abnormalities in Chronic Subjective Tinnitus: A Meta-Analysis.

Front Hum Neurosci. 2017;11:22

Authors: Chen YC, Wang F, Wang J, Bo F, Xia W, Gu JP, Yin X

Abstract
Purpose: The neural mechanisms that give rise to the phantom sound of tinnitus have not been fully elucidated. Neuroimaging studies have revealed abnormalities in resting-state activity that could represent the neural signature of tinnitus, but there is considerable heterogeneity in the data. To address this issue, we conducted a meta-analysis of published neuroimaging studies aimed at identifying a common core of resting-state brain abnormalities in tinnitus patients. Methods: A systematic search was conducted for whole-brain resting-state neuroimaging studies with SPECT, PET and functional MRI that compared chronic tinnitus patients with healthy controls. The authors searched PubMed, Science Direct, Web of Knowledge and Embase databases for neuroimaging studies on tinnitus published up to September 2016. From each study, coordinates were extracted from clusters with significant differences between tinnitus subjects and controls. Meta-analysis was performed using the activation likelihood estimation (ALE) method. Results: Data were included from nine resting-state neuroimaging studies that reported a total of 51 distinct foci. The meta-analysis identified consistent regions of increased resting-state brain activity in tinnitus patients relative to controls that included, bilaterally, the insula, middle temporal gyrus (MTG), inferior frontal gyrus (IFG), parahippocampal gyrus, cerebellum posterior lobe and right superior frontal gyrus. Moreover, decreased brain activity was only observed in the left cuneus and right thalamus. Conclusions: The current meta-analysis is, to our knowledge, the first to demonstrate a characteristic pattern of resting-state brain abnormalities that may serve as neuroimaging markers and contribute to the understanding of neuropathophysiological mechanisms for chronic tinnitus.

PMID: 28174532 [PubMed - in process]

Distributed representation of context by intrinsic subnetworks in prefrontal cortex.

Thu, 02/09/2017 - 12:35
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Distributed representation of context by intrinsic subnetworks in prefrontal cortex.

Proc Natl Acad Sci U S A. 2017 Feb 07;:

Authors: Waskom ML, Wagner AD

Abstract
Human prefrontal cortex supports goal-directed behavior by representing abstract information about task context. The organizational basis of these context representations, and of representations underlying other higher-order processes, is unknown. Here, we use multivariate decoding and analyses of spontaneous correlations to show that context representations are distributed across subnetworks within prefrontal cortex. Examining targeted prefrontal regions, we found that pairs of voxels with similar context preferences exhibited spontaneous correlations that were approximately twice as large as those between pairs with opposite context preferences. This subnetwork organization was stable across task-engaged and resting states, suggesting that abstract context representations are constrained by an intrinsic functional architecture. These results reveal a principle of fine-scaled functional organization in association cortex.

PMID: 28174269 [PubMed - as supplied by publisher]

Intrinsic cerebral activity at resting state in adults with major depressive disorder: A meta-analysis.

Thu, 02/09/2017 - 12:35
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Intrinsic cerebral activity at resting state in adults with major depressive disorder: A meta-analysis.

Prog Neuropsychopharmacol Biol Psychiatry. 2017 Feb 04;:

Authors: Ming Zhou MM, Hu X, Lu Lu MM, Liangqing Zhang MM, Chen L, Gong Q, Huang X

Abstract
Numerous neuroimaging studies have been undertaken to detect cerebral intrinsic activity in major depressive disorder (MDD) with resting state fMRI (rs-fMRI). However, the inconsistent results have hindered our understanding of the exact neuropathology related to MDD. The current meta-analysis used state-of-the-art conjunction analysis techniques to systematically review and summarize all available neuroimaging studies using rs-fMRI with amplitude of low frequency fluctuation (ALFF) and/or fractional ALFF (fALFF) on MDD patients and further explored the effect of antidepressants on the intrinsic activity of the brain. The anisotropic effect size version of signed differential mapping (AES-SDM) was applied to investigate changes in ALFF/fALFF in depression. We performed a subgroup analysis and group comparison on medicated and drug naïve patients to detect drug effect on MDD patients and conjunction analysis to identify congruent results between the two methods. Meta-regression was used to explore the effects of demographics and clinical characteristics. Adult MDD patients showed a robust increase in intrinsic activity in the resting state in the anterior cingulate cortex (ACC) in both ALFF (P<0.001) and fALFF (P<0.01) studies. The subgroup analysis demonstrated that the increased activity in the ACC was prominent in medicated patients only and not seen in drug-naïve MDD patients, while medication-naïve patients showed a specific decreased activity in the cerebellum (P<0.01). Group comparison showed that the intrinsic ACC activity is elevated in medicated MDD patients compared with drug naïve MDD patients. Meta-regression analysis demonstrated that the increased ACC activation was positively correlated with illness duration (P<0.001). Our findings suggest that increased activity of the ACC is more likely to be associated with antidepressant treatment, while decreased intrinsic activity of the cerebellum might be a specific biomarker for current MDD.

PMID: 28174129 [PubMed - as supplied by publisher]

Altered functional connectivity in default mode network in Internet gaming disorder: Influence of childhood ADHD.

Thu, 02/09/2017 - 12:35
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Altered functional connectivity in default mode network in Internet gaming disorder: Influence of childhood ADHD.

Prog Neuropsychopharmacol Biol Psychiatry. 2017 Feb 04;:

Authors: Lee D, Lee J, Lee JE, Jung YC

Abstract
OBJECTIVE: Internet gaming disorder (IGD) is a type of behavioral addiction characterized by abnormal executive control, leading to loss of control over excessive gaming. Attention deficit and hyperactivity disorder (ADHD) is one of the most common comorbid disorders in IGD, involving delayed development of the executive control system, which could predispose individuals to gaming addiction. We investigated the influence of childhood ADHD on neural network features of IGD.
METHODS: Resting-state functional magnetic resonance imaging analysis was performed on 44 young, male IGD subjects with and without childhood ADHD and 19 age-matched, healthy male controls. Posterior cingulate cortex (PCC)-seeded connectivity was evaluated to assess abnormalities in default mode network (DMN) connectivity, which is associated with deficits in executive control.
RESULTS: IGD subjects without childhood ADHD showed expanded functional connectivity (FC) between DMN-related regions (PCC, medial prefrontal cortex, thalamus) compared with controls. These subjects also exhibited expanded FC between the PCC and brain regions implicated in salience processing (anterior insula, orbitofrontal cortex) compared with IGD subjects with childhood ADHD. IGD subjects with childhood ADHD showed expanded FC between the PCC and cerebellum (crus II), a region involved in executive control. The strength of connectivity between the PCC and cerebellum (crus II) was positively correlated with self-reporting scales reflecting impulsiveness.
CONCLUSION: Individuals with IGD showed altered PCC-based FC, the characteristics of which might be dependent upon history of childhood ADHD. Our findings suggest that altered neural networks for executive control in ADHD would be a predisposition for developing IGD.

PMID: 28174127 [PubMed - as supplied by publisher]

Structural and Functional Abnormalities in Children with ADHD: A Focus on Subgenual Anterior Cingulate Cortex.

Thu, 02/09/2017 - 12:35
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Structural and Functional Abnormalities in Children with ADHD: A Focus on Subgenual Anterior Cingulate Cortex.

Brain Connect. 2017 Feb 07;:

Authors: Zhan C, Liu Y, Wu K, Gao Y, Li X

Abstract
Attention-Deficit/Hyperactivity Disorder (ADHD), characterized by developmentally inappropriate inattention, hyperactivity/impulsivity, or a combination of both, is a major public health problem. Neuroimaging studies have revealed associations of these cognitive impairments with structural and functional deficits all over the brain. Existing findings are not fully consistent due to the heterogeneity of study samples and diversity of research techniques. In the current study, we propose to utilize a multi-modal MRI approach to study the structural and functional brain networks in children with ADHD-combined type (ADHD-C) with a focus on the subgenual anterior cingulate cortex (sgACC). Diffusion tensor imaging (DTI) and resting-state functional MRI (rs-fMRI) data from 32 children with ADHD-C and 32 group-matched controls were involved. Network-based statistic (NBS) analysis of the rs-fMRI data revealed a disconnected functional network between the sgACC and multiple regions in the occipital lobe and cerebellum, whereas the DTI data showed disrupted white matter integrity in the subgenual cingulum bundle (sgCB). Post hoc Region-of-Interest (ROI)-based analyses showed significantly increased fluctuation of the spontaneous brain activity in the sgACC and higher radial diffusivity in the sgCB in the ADHD group. Both the rs-fMRI and DTI ROI-based measures were significantly correlated with clinical measures that examine behavioral capacities of attention and inhibitory control. Findings of this study suggest that functional alterations in the sgACC and white matter underdevelopment in the sgCB may impact each other, and together contribute to impaired attention and inhibitory control function in children with ADHD.

PMID: 28173729 [PubMed - as supplied by publisher]

Tai Chi Chuan and Baduanjin practice modulates functional connectivity of the cognitive control network in older adults.

Thu, 02/09/2017 - 12:35
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Tai Chi Chuan and Baduanjin practice modulates functional connectivity of the cognitive control network in older adults.

Sci Rep. 2017 Feb 07;7:41581

Authors: Tao J, Chen X, Egorova N, Liu J, Xue X, Wang Q, Zheng G, Li M, Hong W, Sun S, Chen L, Kong J

Abstract
Cognitive impairment is one of the most common problem saffecting older adults. In this study, we investigated whether Tai Chi Chuan and Baduanjin practice can modulate mental control functionand the resting state functional connectivity (rsFC) of the cognitive control network in older adults. Participants in the two exercise groups practiced either Tai Chi Chuan or Baduanjin for 12 weeks, and those in the control group received basic health education. Memory tests and fMRI scans were conducted at baseline and at the end of the study. Seed-based (bilateral dorsolateral prefrontal cortex, DLPFC) rsFC analysis was performed. We found that compared to the controls, 1) both Tai Chi Chuan and Baduanjin groups demonstrated significant improvements in mental control function; 2) the Tai Chi Chuan group showed a significant decrease in rsFC between the DLPFC and the left superior frontal gyrus (SFG) and anterior cingulate cortex; and 3) the Baduanjin group showed a significant decrease in rsFC between the DLPFC and the left putamen and insula. Mental control improvement was negatively associated with rsFC DLPFC-putamen changes across all subjects. These findings demonstrate the potential of Tai Chi Chuan and Baduanjin exercises in preventing cognitive decline.

PMID: 28169310 [PubMed - in process]

Validation of impedance cardiography in pulmonary arterial hypertension.

Thu, 02/09/2017 - 12:35
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Validation of impedance cardiography in pulmonary arterial hypertension.

Clin Physiol Funct Imaging. 2017 Feb 06;:

Authors: Panagiotou M, Vogiatzis I, Jayasekera G, Louvaris Z, Mackenzie A, Mcglinchey N, Baker JS, Church AC, Peacock AJ, Johnson MK

Abstract
BACKGROUND: Non-invasive methods of measuring cardiac output are highly desirable in pulmonary arterial hypertension (PAH). We therefore sought to validate impedance cardiography (ICG) against thermodilution (TD) and cardiac magnetic resonance (CMR) in the measurement of cardiac output in patients under investigation for PAH.
METHODS: A prospective, cross-sectional study was performed to compare single-point measurements of cardiac output obtained by impedance cardiography (COICG ) technology (PhysioFlow(®) ) with (i) contemporaneous TD measurements (COTD ) at rest and steady-state exercise during right heart catheterization and (ii) CMR measurements (COCMR ) at rest obtained within 72 h.
RESULTS: Paired COICG and COTD measurements were obtained in 25 subjects at rest and 16 subjects at exercise. COCMR measurements were obtained in 16 subjects at rest. There was unsatisfactory correlation and agreement between COICG and COTD at rest (r = 0·42, P = 0·035; bias: 1·21 l min(-1) , 95% CI: -2·33 to 4·75 l min(-1) ) and exercise (r = .65, P = .007; bias: 1·41 l min(-1) ; 95% CI: -3·99 to 6·81 l min(-1) ) and in the change in COICG and COTD from rest to exercise (r = 0·53, P = 0·033; bias: 0·76 l min(-1) , 95% CI: -3·74 to 5·26 l min(-1) ). There was also a lack of correlation and unsatisfactory agreement between resting COICG and COCMR (r = 0·38, P = 0·1; bias: 1·40 l min(-1) , 95% CI: -2·48 to 5·28 l min(-1) ). In contrast, there was close correlation and agreement between resting COTD and COCMR (r = 0·87, P<0·001; bias: -0·16 l min(-1) , 95% CI: -1·97 to 1·65).
CONCLUSIONS: In a representative population of patients under investigation for PAH, ICG showed insufficient qualitative and quantitative value in the measurement of resting and exercise cardiac output when compared with TD and CMR.

PMID: 28168802 [PubMed - as supplied by publisher]

White matter predicts functional connectivity in premanifest Huntington's disease.

Thu, 02/09/2017 - 12:35
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White matter predicts functional connectivity in premanifest Huntington's disease.

Ann Clin Transl Neurol. 2017 Feb;4(2):106-118

Authors: McColgan P, Gregory S, Razi A, Seunarine KK, Gargouri F, Durr A, Roos RA, Leavitt BR, Scahill RI, Clark CA, Tabrizi SJ, Rees G, and the Track On‐HD Investigators, Coleman A, Decolongon J, Fan M, Petkau T, Jauffret C, Justo D, Lehericy S, Nigaud K, Valabrègue R, Choonderbeek A, Hart EP, Hensman Moss DJ, Crawford H, Johnson E, Papoutsi M, Berna C, Reilmann R, Weber N, Stout J, Labuschagne I, Landwehrmeyer B, Orth M, Johnson H

Abstract
OBJECTIVES: The distribution of pathology in neurodegenerative disease can be predicted by the organizational characteristics of white matter in healthy brains. However, we have very little evidence for the impact these pathological changes have on brain function. Understanding any such link between structure and function is critical for understanding how underlying brain pathology influences the progressive behavioral changes associated with neurodegeneration. Here, we demonstrate such a link between structure and function in individuals with premanifest Huntington's.
METHODS: Using diffusion tractography and resting state functional magnetic resonance imaging to characterize white matter organization and functional connectivity, we investigate whether characteristic patterns of white matter organization in the healthy human brain shape the changes in functional coupling between brain regions in premanifest Huntington's disease.
RESULTS: We find changes in functional connectivity in premanifest Huntington's disease that link directly to underlying patterns of white matter organization in healthy brains. Specifically, brain areas with strong structural connectivity show decreases in functional connectivity in premanifest Huntington's disease relative to controls, while regions with weak structural connectivity show increases in functional connectivity. Furthermore, we identify a pattern of dissociation in the strongest functional connections between anterior and posterior brain regions such that anterior functional connectivity increases in strength in premanifest Huntington's disease, while posterior functional connectivity decreases.
INTERPRETATION: Our findings demonstrate that organizational principles of white matter underlie changes in functional connectivity in premanifest Huntington's disease. Furthermore, we demonstrate functional antero-posterior dissociation that is in keeping with the caudo-rostral gradient of striatal pathology in HD.

PMID: 28168210 [PubMed]

Commentary: Selective Development of Anticorrelated Networks in the Intrinsic Functional Organization of the Human Brain.

Thu, 02/09/2017 - 12:35
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Commentary: Selective Development of Anticorrelated Networks in the Intrinsic Functional Organization of the Human Brain.

Front Hum Neurosci. 2017;11:13

Authors: Arsalidou M, Sharaev MG, Kotova T, Martynova O

PMID: 28167907 [PubMed - in process]

Proportional thresholding in resting-state fMRI functional connectivity networks and consequences for patient-control connectome studies: Issues and recommendations.

Thu, 02/09/2017 - 12:35
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Proportional thresholding in resting-state fMRI functional connectivity networks and consequences for patient-control connectome studies: Issues and recommendations.

Neuroimage. 2017 Feb 03;:

Authors: van den Heuvel M, de Lange S, Zalesky A, Seguin C, Yeo T, Schmidt R

Abstract
Graph theoretical analysis has become an important tool in the examination of brain dysconnectivity in neurological and psychiatric brain disorders. A common analysis step in the construction of the functional graph or network involves "thresholding" of the connectivity matrix, selecting the set of edges that together form the graph on which network organization is evaluated. To avoid systematic differences in absolute number of edges, studies have argued against the use of an "absolute threshold" in case-control studies and have proposed the use of "proportional thresholding" instead, in which a pre-defined number of strongest connections are selected as network edges, ensuring equal network density across datasets. Here, we systematically studied the effect of proportional thresholding on the construction of functional matrices and subsequent graph analysis in patient-control functional connectome studies. In a few simple experiments we show that differences in overall strength of functional connectivity (FC) - as often observed between patients and controls - can have predictable consequences for between-group differences in network organization. In individual networks with lower overall FC the proportional thresholding algorithm has to select more edges based on lower correlations, which have a higher probability of being spurious and thus introduces a higher degree of randomness in the resulting network. We show across both empirical and artificial patient-control datasets that lower levels of overall FC in either the patient or control group will most often lead to differences in network efficiency and clustering, suggesting that differences in FC across subjects will be artificially inflated or translated into differences in network organization. Based on the presented case-control findings we inform about the caveats of proportional thresholding in patient-control studies in which groups show a between-group difference in overall FC. We make recommendations for disease connectome studies on how to examine, report and to take into account overall FC effects in future patient-control studies.

PMID: 28167349 [PubMed - as supplied by publisher]

Brain network alterations in the inflammatory soup animal model of migraine.

Thu, 02/09/2017 - 12:35
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Brain network alterations in the inflammatory soup animal model of migraine.

Brain Res. 2017 Feb 03;:

Authors: Becerra L, Bishop J, Barmettler G, Kainz V, Burstein R, Borsook D

Abstract
Advances in our understanding of the human pain experience have shifted much of the focus of pain research from the periphery to the brain. Current hypotheses suggest that the progression of migraine depends on abnormal functioning of neurons in multiple brain regions. Accordingly, we sought to capture functional brain changes induced by the application of an inflammatory cocktail known as inflammatory soup (IS), to the dura mater across multiple brain networks. Specifically, we aimed to determine whether IS alters additional neural networks indirectly related to the primary nociceptive pathways via the spinal cord to the thalamus and cortex. IS comprises an acidic combination of bradykinin, serotonin, histamine and prostaglandin PGE2 and was introduced to basic pain research as a tool to activate and sensitize peripheral nociceptors when studying pathological pain conditions associated with allodynia and hyperalgesia. Using this model of intracranial pain, we found that dural application of IS in awake, fully conscious, rats enhanced thalamic, hypothalamic, hippocampal and somatosensory cortex responses to mechanical stimulation of the face (compared to sham synthetic interstitial fluid administration). Furthermore, resting state MRI data revealed altered functional connectivity in a number of networks previously identified in clinical chronic pain populations. These included the default mode, sensorimotor, interoceptive (Salience) and autonomic networks. The findings suggest that activation and sensitization of meningeal nociceptors by IS can enhance the extent to which the brain processes nociceptive signaling, define new level of modulation of affective and cognitive responses to pain; set new tone for hypothalamic regulation of autonomic outflow to the cranium; and change cerebellar functions.

PMID: 28167076 [PubMed - as supplied by publisher]

Clinical significance of increased cerebellar default-mode network connectivity in resting-state patients with drug-naive somatization disorder.

Thu, 02/09/2017 - 12:35
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Clinical significance of increased cerebellar default-mode network connectivity in resting-state patients with drug-naive somatization disorder.

Medicine (Baltimore). 2016 Jul;95(28):e4043

Authors: Wang H, Guo W, Liu F, Chen J, Wu R, Zhang Z, Yu M, Li L, Zhao J

Abstract
The cerebellum has been proven to be connected to the brain network, as in the default-mode network (DMN), among healthy subjects and patients with psychiatric disorders. However, whether or not abnormal cerebellar DMN connectivity exists and what its clinical significance is among drug-naive patients with somatization disorder (SD) at rest remain unclear.A total of 25 drug-naive patients with SD and 28 healthy controls were enrolled for a resting-state scan. The imaging data were analyzed using the seed-based functional connectivity (FC) method.Compared with the controls, patients with SD showed increased left/right Crus I-left/right angular gyrus (AG) connectivity and Lobule IX-left superior medial prefrontal cortex (MPFC) connectivity. The FC values of the left/right Crus I-right AG connectivity of the patients were positively correlated with their scores in the somatization subscale of the symptom checklist-90 (Scl-90). A trend level of correlations was observed between the FC values of the left Crus I-left AG connectivity of the patients and their scores for the somatization subscale of Scl-90, as well as between the FC values of their Lobule IX-left superior MPFC connectivity and their scores for the Eysenck personality questionnaire (EPQ) extraversion.Our findings show the increased cerebellar DMN connectivity in patients with SD and therefore highlight the importance of the DMN in the neurobiology of SD. Increased cerebellar DMN connectivities are also correlated with their somatization severity and personality, both of which bear clinical significance.

PMID: 27428190 [PubMed - indexed for MEDLINE]

On the Detection of High Frequency Correlations in Resting State fMRI.

Tue, 02/07/2017 - 12:05
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On the Detection of High Frequency Correlations in Resting State fMRI.

Neuroimage. 2017 Feb 02;:

Authors: Trapp C, Vakamudi K, Posse S

Abstract
Current studies of resting-state connectivity rely on coherent signal fluctuations at frequencies below 0.1 Hz, however, recent studies using high-speed fMRI have shown that fluctuations above 0.5 Hz may exist. This study replicates the feasibility of measuring high frequency (HF) correlations in six healthy controls and a patient with a brain tumor while analyzing non-physiological signal sources via simulation. Resting-state data were acquired using a high-speed multi-slab echo-volumar imaging pulse sequence with 136 ms temporal resolution. Bandpass frequency filtering in combination with sliding window seed-based connectivity analysis using running mean of the correlation maps was employed to map HF correlations up to 3.7 Hz. Computer simulations of Rician noise and the underlying point spread function were analyzed to estimate baseline spatial autocorrelation levels in four major networks (auditory, sensorimotor, visual, and default-mode). Using seed regions based on Brodmann areas, the auditory and default-mode networks were observed to have significant frequency band dependent HF correlations above baseline spatial autocorrelation levels. Correlations in the sensorimotor network were at trend level. The auditory network was still observed using a unilateral single voxel seed. In the patient, HF auditory correlations showed a spatial displacement near the tumor consistent with the displacement seen at low frequencies. In conclusion, our data suggest that HF connectivity in the human brain may be observable with high-speed fMRI, however, the detection sensitivity may depend on the network observed, data acquisition technique, and analysis method.

PMID: 28163143 [PubMed - as supplied by publisher]

Neuromodulation in response to electroconvulsive therapy in schizophrenia and major depression.

Tue, 02/07/2017 - 12:05
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Neuromodulation in response to electroconvulsive therapy in schizophrenia and major depression.

Brain Stimul. 2017 Jan 16;:

Authors: Thomann PA, Wolf RC, Nolte HM, Hirjak D, Hofer S, Seidl U, Depping MS, Stieltjes B, Maier-Hein K, Sambataro F, Wüstenberg T

Abstract
BACKGROUND: Electroconvulsive therapy (ECT) is one of the most effective treatments in severe and treatment-resistant major depressive disorder (MDD). ECT has been also shown to be effective in schizophrenia (SZ), particularly when rapid symptom reduction is needed or in cases of resistance to drug-treatment. However, its precise mechanisms of action remain largely unknown.
OBJECTIVE/HYPOTHESIS: This study examined whether ECT exerts disorder-specific or unspecific modulation of brain structure and function in SZ and MDD.
METHODS: We investigated neuromodulatory effects of right-sided unilateral ECT in pharmacoresistant patients with SZ or MDD. Magnetic resonance imaging was conducted before and after ECT to investigate treatment-related effects on brain structure and function. Imaging data were analyzed by means of Voxel Based Morphometry and Resting State Functional Connectivity (RSFC) methods.
RESULTS: Right unilateral ECT induced transdiagnostic regional increases of limbic gray matter and modulations of neural coupling at rest. Structural effects were accompanied by a decrease in RSFC within temporoparietal, prefrontal and cortical midline structures, and an increase in hypothalamic RSFC. The extent of structural and functional change was partially inversely associated with the baseline measures.
CONCLUSION: The present findings provide first evidence for transdiagnostic changes of brain structure together with modulation of brain function after ECT. The data indicate diagnosis-unspecific mechanisms of action with respect to regional gray matter volume and resting-state functional connectivity.

PMID: 28162976 [PubMed - as supplied by publisher]

[Difference in imaging and metal metabolism between hepatic and cerebral type Wilson disease].

Tue, 02/07/2017 - 12:05
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[Difference in imaging and metal metabolism between hepatic and cerebral type Wilson disease].

Zhonghua Yi Xue Za Zhi. 2017 Jan 17;97(3):176-181

Authors: Zhou XX, Li XH, Pu XY, Qin HL, Li XB, Chu JP, Yang ZY, Huang HW, Liang XL

Abstract
Objective: To evaluate the difference of metal metabolism, damage to structure and functional activity in brains between hepatic and cerebral type Wilson disease (WD). Methods: Forty patients with WD, including 20 with cerebral type and 20 with hepatic type, and 20 age-matched healthy controls in the First Affiliated Hospital, Sun Yat-sen University between Jul 2013 and May 2016 were enrolled.All study subjects underwent diffusion tensor imaging (DTI), resting state functional MRI (rs-fMRI) and susceptibility weighted imaging (SWI) of the brain.Six regions of interest (ROIs) were chosen.The values of fractional anisotropy (FA), λ in ROIs were determined on DTI, FA and fiber volumes between ROIs were also determined on DTI.The values of amplitude of low frequency fluctuation (ALFF) and regional homogeneity (REHO) in ROIs were determined on rs-fMRI.The values of corrected phase (CP) were calculated on SWI.The copper and iron content were measured.The difference of imaging and metal metrics between cerebral type and hepatic type WD were evaluated. Results: DTI metrics differed between patients with the cerebral and hepatic types of WD.ALFF values in the caudate nucleus, and thalamus were lower (P=0.037, 0.040), and REHO values in the caudate nucleus were lower (P=0.029), in patients of cerebral type than in hepatic type patients.CP values of the right caudate nucleus and left putamen in cerebral type WD patients were lower than in hepatic type patients (P=0.020, 0.23). The serum iron content of hepatic type WD patients was higher than the normal (P=0.013), and the urine copper content was higher than the cerebral type patients (P=0.021). Conclusions: Metal deposition and damage to the structure and functional activity in the brain may occur in hepatic type WD patients.The structural and functional activity damage of the brain in hepatic type is less severe than that in cerebral type patients, while the metal deposition is not significant different between hepatic and cerebral type.

PMID: 28162166 [PubMed - in process]

resting state fMRI; +21 new citations

Mon, 02/06/2017 - 11:50

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Assessment of segmental myocardial blood flow and myocardial perfusion reserve by adenosine-stress myocardial arterial spin labeling perfusion imaging.

Fri, 02/03/2017 - 22:50

Assessment of segmental myocardial blood flow and myocardial perfusion reserve by adenosine-stress myocardial arterial spin labeling perfusion imaging.

J Magn Reson Imaging. 2017 Feb 02;:

Authors: Yoon AJ, Do HP, Cen S, Fong MW, Saremi F, Barr ML, Nayak KS

Abstract
PURPOSE: To determine the feasibility of measuring increases in myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) on a per-segment basis using arterial spin labeled (ASL) magnetic resonance imaging (MRI) with adenosine vasodilator stress in normal human myocardium.
MATERIALS AND METHODS: Myocardial ASL scans at rest and during adenosine infusion were incorporated into a routine 3T MR adenosine-induced vasodilator stress protocol and were performed in 10 healthy human volunteers. Myocardial ASL was performed using single-gated flow-sensitive alternating inversion recovery (FAIR) tagging and balanced steady-state free precession (bSSFP) imaging at 3T. A T2 -prep blood oxygen level-dependent (BOLD) SSFP sequence was used to concurrently assess segmental myocardial oxygenation with BOLD signal intensity (SI) percent change in the same subjects.
RESULTS: There was a statistically significant difference between MBF measured by ASL at rest (1.75 ± 0.86 ml/g/min) compared to adenosine stress (4.58 ± 2.14 ml/g/min) for all wall segments (P < 0.0001), yielding a per-segment MPR of 3.02 ± 1.51. When wall segments were divided into specific segmental myocardial perfusion territories (ie, anteroseptal, anterior, anterolateral, inferolateral, inferior, and inferoseptal), the differences between rest and stress regional MBF for each territory remained consistently statistically significant (P < 0.001) after correcting for multiple comparisons.
CONCLUSION: This study demonstrates the feasibility of measuring MBF and MPR on a segmental basis by single-gated cardiac ASL in normal volunteers. Second, this study demonstrates the feasibility of performing the ASL sequence and T2 -prepared SSFP BOLD imaging during a single adenosine infusion.
LEVEL OF EVIDENCE: 2 J. Magn. Reson. Imaging 2017.

PMID: 28152238 [PubMed - as supplied by publisher]

Spontaneous brain activity in the sensorimotor cortex in amyotrophic lateral sclerosis can be negatively regulated by corticospinal fiber integrity.

Fri, 02/03/2017 - 22:50
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Spontaneous brain activity in the sensorimotor cortex in amyotrophic lateral sclerosis can be negatively regulated by corticospinal fiber integrity.

Neurol Sci. 2017 Feb 01;:

Authors: Sako W, Abe T, Izumi Y, Yamazaki H, Matsui N, Harada M, Kaji R

Abstract
Previous studies failed to detect reduced value of the amplitude of low frequency fluctuation (ALFF) derived from resting state functional magnetic resonance imaging in the primary motor cortex in amyotrophic lateral sclerosis (ALS) though primary motor cortex was mainly affected with ALS. We aimed to investigate the cause of masking the abnormality in the primary motor cortex in ALS and usefulness of ALFF for differential diagnosis among diseases showing muscle weakness. We enrolled ten patients with ALS and eleven disease controls showing muscle weakness. Voxel-wise analysis revealed that significant reduction of ALFF value was present in the right sensorimotor cortex in ALS. There was a significant negative correlation between ALFF value in the right sensorimotor cortex and fractional anisotropy (FA) value in the posterior limbs of the internal capsule (PLIC). For a diagnostic tool, the area under receiver operating characteristic curve improved if the ALS patients with disease duration >1 year were excluded. The present findings raised the possibility of usefulness of ALFF value in the sensorimotor cortex for differential diagnosis of ALS, and supported the notion that adjustment for FA value in the PLIC could improve accuracy.

PMID: 28150100 [PubMed - as supplied by publisher]

Reveal Consistent Spatial-Temporal Patterns from Dynamic Functional Connectivity for Autism Spectrum Disorder Identification.

Fri, 02/03/2017 - 22:50
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Reveal Consistent Spatial-Temporal Patterns from Dynamic Functional Connectivity for Autism Spectrum Disorder Identification.

Med Image Comput Comput Assist Interv. 2016 Oct;9900:106-114

Authors: Zhu Y, Zhu X, Zhang H, Gao W, Shen D, Wu G

Abstract
Functional magnetic resonance imaging (fMRI) provides a non-invasive way to investigate brain activity. Recently, convergent evidence shows that the correlations of spontaneous fluctuations between two distinct brain regions dynamically change even in resting state, due to the condition-dependent nature of brain activity. Thus, quantifying the patterns of functional connectivity (FC) in a short time period and changes of FC over time can potentially provide valuable insight into both individual-based diagnosis and group comparison. In light of this, we propose a novel computational method to robustly estimate both static and dynamic spatial-temporal connectivity patterns from the observed noisy signals of individual subject. We achieve this goal in two folds: (1) Construct static functional connectivity across brain regions. Due to low signal-to-noise ratio induced by possible non-neural noise, the estimated FC strength is very sensitive and it is hard to define a good threshold to distinguish between real and spurious connections. To alleviate this issue, we propose to optimize FC which is in consensus with not only the low level region-to-region signal correlations but also the similarity of high level principal connection patterns learned from the estimated link-to-link connections. Since brain network is intrinsically sparse, we also encourage sparsity during FC optimization. (2) Characterize dynamic functional connectivity along time. It is hard to synchronize the estimated dynamic FC patterns and the real cognitive state changes, even using learning-based methods. To address these limitations, we further extend above FC optimization method into the spatial-temporal domain by arranging the FC estimations along a set of overlapped sliding windows into a tensor structure as the window slides. Then we employ low rank constraint in the temporal domain assuming there are likely a small number of discrete states that the brain transverses during a short period of time. We applied the learned spatial-temporal patterns from fMRI images to identify autism subjects. Promising classification results have been achieved, suggesting high discrimination power and great potentials in computer assisted diagnosis.

PMID: 28149963 [PubMed - in process]

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