Zang YF papers

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Frequency-dependent changes in the amplitude of low-frequency fluctuations in internet gaming disorder.

Sat, 10/17/2015 - 21:01
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Frequency-dependent changes in the amplitude of low-frequency fluctuations in internet gaming disorder.

Front Psychol. 2015;6:1471

Authors: Lin X, Jia X, Zang YF, Dong G

Abstract
Neuroimaging studies have revealed that the task-related functional brain activities are impaired in internet gaming disorder (IGD) subjects. However, little is known about the alternations in spontaneous brain activities about them. Recent studies have proposed that the brain activities of different frequency ranges are generated by different nervous activities and have different physiological and psychological functions. Thus, in this study, we set to explore the spontaneous brain activities in IGD subjects by measuring the fractional amplitude of low-frequency fluctuation (fALFF), to investigate band-specific changes of resting-state fALFF. We subdivided the frequency range into five bands based on literatures. Comparing to healthy controls, the IGD group showed decreased fALFF values in the cerebellum posterior lobe and increased fALFF values in superior temporal gyrus. Significant interactions between frequency bands and groups were found in the cerebellum, the anterior cingulate, the lingual gyrus, the middle temporal gyrus, and the middle frontal gyrus. Those brain regions are proved related to the executive function and decision-making. These results revealed the changed spontaneous brain activity of IGD, which contributed to understanding the underlying pathophysiology of IGD.

PMID: 26441815 [PubMed]

Exploring Dynamic Brain Functional Networks Using Continuous "State-Related" Functional MRI.

Wed, 10/07/2015 - 09:01
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Exploring Dynamic Brain Functional Networks Using Continuous "State-Related" Functional MRI.

Biomed Res Int. 2015;2015:824710

Authors: Li X, Zang YF, Zhang H

Abstract
We applied a "temporal decomposition" method, which decomposed a single brain functional network into several "modes"; each of them dominated a short temporal period, on a continuous, "state-" related, "finger-force feedback" functional magnetic resonance imaging experiment. With the hypothesis that attention and internal/external information processing interaction could be manipulated by different (real and sham) feedback conditions, we investigated functional network dynamics of the "default mode," "executive control," and sensorimotor networks. They were decomposed into several modes. During real feedback, the occurrence of "default mode-executive control competition-related" mode was higher than that during sham feedback (P = 0.0003); the "default mode-visual facilitation-related" mode more frequently appeared during sham than real feedback (P = 0.0004). However, the dynamics of the sensorimotor network did not change significantly between two conditions (P > 0.05). Our results indicated that the visual-guided motor feedback involves higher cognitive functional networks rather than primary motor network. The dynamics monitoring of inner and outside environment and multisensory integration could be the mechanisms. This study is an extension of our previous region-specific and static-styled study of our brain functional architecture.

PMID: 26413546 [PubMed - as supplied by publisher]

Frequency-Specific Alterations of Local Synchronization in Idiopathic Generalized Epilepsy.

Tue, 09/29/2015 - 02:00
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Frequency-Specific Alterations of Local Synchronization in Idiopathic Generalized Epilepsy.

Medicine (Baltimore). 2015 Aug;94(32):e1374

Authors: Wang J, Zhang Z, Ji GJ, Xu Q, Huang Y, Wang Z, Jiao Q, Yang F, Zang YF, Liao W, Lu G

Abstract
Recurrently and abnormally hypersynchronous discharge is a striking feature of idiopathic generalized epilepsy (IGE). Resting-state functional magnetic resonance imaging has revealed aberrant spontaneous brain synchronization, predominately in low-frequency range (<0.1 Hz), in individuals with IGE. Little is known, however, about these changes in local synchronization across different frequency bands. We examined alterations to frequency-specific local synchronization in terms of spontaneous blood oxygen level-dependent (BOLD) fluctuations across 5 bands, spanning 0 to 0.25 Hz. Specifically, we compared brain activity in a large cohort of IGE patients (n = 86) to age- and sex-matched normal controls (n = 86). IGE patients showed decreased local synchronization in low frequency (<0.073 Hz), primarily in the default mode network (DMN). IGE patients also exhibited increased local synchronization in high-frequency (>0.073 Hz) in a "conscious perception network," which is anchored by the pregenual and dorsal anterior cingulate cortex, as well as the bilateral insular cortices, possibly contributing to impaired consciousness. Furthermore, we found frequency-specific alternating local synchronization in the posterior portion of the DMN relative to the anterior part, suggesting an interaction between the disease and frequency bands. Importantly, the aberrant high-frequency local synchronization in the middle cingulate cortex was associated with disease duration, thus linking BOLD frequency changes to disease severity. These findings provide an overview of frequency-specific local synchronization of BOLD fluctuations, and may be helpful in uncovering abnormal synchronous neuronal activity in patients with IGE at specific frequency bands.

PMID: 26266394 [PubMed - as supplied by publisher]

Local Activity and Causal Connectivity in Children with Benign Epilepsy with Centrotemporal Spikes.

Thu, 08/13/2015 - 08:30
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Local Activity and Causal Connectivity in Children with Benign Epilepsy with Centrotemporal Spikes.

PLoS One. 2015;10(7):e0134361

Authors: Wu Y, Ji GJ, Zang YF, Liao W, Jin Z, Liu YL, Li K, Zeng YW, Fang F

Abstract
The aim of the current study was to localize the epileptic focus and characterize its causal relation with other brain regions, to understand the cognitive deficits in children with benign childhood epilepsy with centrotemporal spikes (BECTS). Resting-state functional magnetic resonance imaging (fMRI) was performed in 37 children with BECTS and 25 children matched for age, sex and educational achievement. We identified the potential epileptogenic zone (EZ) by comparing the amplitude of low frequency fluctuation (ALFF) of spontaneous blood oxygenation level dependent fMRI signals between the groups. Granger causality analysis was applied to explore the causal effect between EZ and the whole brain. Compared with controls, children with BECTS had significantly increased ALFF in the right postcentral gyrus and bilateral calcarine, and decreased ALFF in the left anterior cingulate cortex, bilateral putaman/caudate, and left cerebellum. ALFF values in the putaman/caudate were positively correlated with verbal IQ scores in patients. The ALFF values in cerebellum and performance IQ scores were negatively correlated in patients. These results suggest that ALFF disturbances in the putaman/caudate and cerebellum play an important role in BECTS cognitive dysfunction. Compared with controls, the patients showed increased driving effect from the EZ to the right medial frontal cortex and posterior cingulate cortex and decreased causal effects from the EZ to left inferior frontal gyrus. The causal effect of the left inferior frontal gyrus negatively correlated with disease duration, which suggests a relation between the epileptiform activity and language impairment. All together, these findings provide additional insight into the neurophysiological mechanisms of epilepitogenisis and cognitive dysfunction associated with BECTS.

PMID: 26225427 [PubMed - as supplied by publisher]

DynamicBC: a MATLAB toolbox for dynamic brain connectome analysis.

Fri, 07/31/2015 - 19:30
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DynamicBC: a MATLAB toolbox for dynamic brain connectome analysis.

Brain Connect. 2014 Dec;4(10):780-90

Authors: Liao W, Wu GR, Xu Q, Ji GJ, Zhang Z, Zang YF, Lu G

Abstract
The brain connectome collects the complex network architectures, looking at both static and dynamic functional connectivity. The former normally requires stationary signals and connections. However, the human brain activity and connections are most likely time dependent and dynamic, and related to ongoing rhythmic activity. We developed an open-source MATLAB toolbox DynamicBC with user-friendly graphical user interfaces, implementing both dynamic functional and effective connectivity for tracking brain dynamics from functional MRI. We provided two strategies for dynamic analysis: (1) the commonly utilized sliding-window analysis and (2) the flexible least squares based time-varying parameter regression strategy. The toolbox also implements multiple functional measures including seed-to-voxel analysis, region of interest (ROI)-to-ROI analysis, and voxel-to-voxel analysis. We describe the principles of the implemented algorithms, and then present representative results from simulations and empirical data applications. We believe that this toolbox will help neuroscientists and neurologists to easily map dynamic brain connectomics.

PMID: 25083734 [PubMed - indexed for MEDLINE]

An fMRI Study of Local Synchronization in Different Subfrequency Bands during the Continuous Feedback of Finger Force.

Thu, 07/23/2015 - 10:30
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An fMRI Study of Local Synchronization in Different Subfrequency Bands during the Continuous Feedback of Finger Force.

Biomed Res Int. 2015;2015:273126

Authors: Zhang H, Gao ZZ, Zang YF

Abstract
Conventional functional magnetic resonance imaging (fMRI) studies on motor feedback employ periodical blocked paradigm which does not allow frequency analysis of brain activity. Here, we carried out an fMRI study by using a continuous paradigm, that is, continuous (8 min) feedback of finger force. Borrowing an analytic method widely used in resting-state fMRI studies, that is, regional homogeneity (ReHo), we compared the local synchronization in some subfrequency bands between real and sham feedback, and the subbands were defined as Slow-6 (0.0-0.01 Hz), Slow-5 (0.01-0.027 Hz), Slow-4 (0.027-0.073 Hz), Slow-3 (0.073-0.198 Hz), and Slow-2 (0.198-0.25 Hz). Our results revealed that the five subfrequency bands of brain activity contributed to the changes of ReHo between real and sham feedback differently, and, more importantly, the changes in basal ganglia were only manifested in Slow-6, implicating the fact that ReHo in ultraslow band may be associated with the functional significance of BG, that is, motor control. These findings provide novel insights into the neural substrate underlying motor feedback, and properties of the ultraslow band of local synchronization deserve more attention in future explorations.

PMID: 26180789 [PubMed - as supplied by publisher]

Intrinsic brain activity as a diagnostic biomarker in children with benign epilepsy with centrotemporal spikes.

Fri, 07/17/2015 - 03:30
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Intrinsic brain activity as a diagnostic biomarker in children with benign epilepsy with centrotemporal spikes.

Hum Brain Mapp. 2015 Jul 14;

Authors: Zhu Y, Yu Y, Shinkareva SV, Ji GJ, Wang J, Wang ZJ, Zang YF, Liao W, Tang YL

Abstract
Benign epilepsy with centrotemporal spikes (BECTS) is often associated with neural circuit dysfunction, particularly during the transient active state characterized by interictal epileptiform discharges (IEDs). Little is known, however, about the functional neural circuit abnormalities in BECTS without IEDs, or if such abnormalities could be used to differentiate BECTS patients without IEDs from healthy controls (HCs) for early diagnosis. To this end, we conducted resting-state functional magnetic resonance imaging (RS-fMRI) and simultaneous Electroencephalogram (EEG) in children with BECTS (n = 43) and age-matched HC (n = 28). The simultaneous EEG recordings distinguished BECTS with IEDs (n = 20) from without IEDs (n = 23). Intrinsic brain activity was measured in all three groups using the amplitude of low frequency fluctuation at rest. Compared to HC, BECTS patients with IEDs exhibited an intrinsic activity abnormality in the thalamus, suggesting that thalamic dysfunction could contribute to IED emergence while patients without IEDs exhibited intrinsic activity abnormalities in middle frontal gyrus and superior parietal gyrus. Using multivariate pattern classification analysis, we were able to differentiate BECTS without IEDs from HCs with 88.23% accuracy. BECTS without epileptic transients can be distinguished from HC and BECTS with IEDs by unique regional abnormalities in resting brain activity. Both transient abnormalities as reflected by IEDs and chronic abnormalities as reflected by RS-fMRI may contribute to BECTS development and expression. Intrinsic brain activity and multivariate pattern classification techniques are promising tools to diagnose and differentiate BECTS syndromes. Hum Brain Mapp, 2015. © 2015 Wiley Periodicals, Inc.

PMID: 26173095 [PubMed - as supplied by publisher]

Toward a Meta-Analytic Synthesis of the Resting-State fMRI Literature for Clinical Populations.

Fri, 07/17/2015 - 03:30
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Toward a Meta-Analytic Synthesis of the Resting-State fMRI Literature for Clinical Populations.

Biomed Res Int. 2015;2015:435265

Authors: Zang YF, Zuo XN, Milham M, Hallett M

PMID: 26171391 [PubMed - in process]

Dynamical intrinsic functional architecture of the brain during absence seizures.

Wed, 07/15/2015 - 02:00
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Dynamical intrinsic functional architecture of the brain during absence seizures.

Brain Struct Funct. 2014 Nov;219(6):2001-15

Authors: Liao W, Zhang Z, Mantini D, Xu Q, Ji GJ, Zhang H, Wang J, Wang Z, Chen G, Tian L, Jiao Q, Zang YF, Lu G

Abstract
Epilepsy is characterized by recurrent and temporary brain dysfunction due to discharges of interconnected groups of neurons. The brain of epilepsy patients has a dynamic bifurcation that switches between epileptic and normal states. The dysfunctional state involves large-scale brain networks. It is very important to understand the network mechanisms of seizure initiation, maintenance, and termination in epilepsy. Absence epilepsy provides a unique model for neuroimaging investigation on dynamic evolutions of brain networks over seizure repertoire. By using a dynamic functional connectivity and graph theoretical analyses to study absence seizures (AS), we aimed to obtain transition of network properties that account for seizure onset and offset. We measured resting-state functional magnetic resonance imaging and simultaneous electroencephalography (EEG) from children with AS. We used simultaneous EEG to define the preictal, ictal and postictal intervals of seizures. We measured dynamic connectivity maps of the thalamus network and the default mode network (DMN), as well as functional connectome topologies, during the three different seizure intervals. The analysis of dynamic changes of anti-correlation between the thalamus and the DMN is consistent with an inhibitory effect of seizures on the default mode of brain function, which gradually fades out after seizure onset. Also, we observed complex transitions of functional network topology, implicating adaptive reconfiguration of functional brain networks. In conclusion, our work revealed novel insights into modifications in large-scale functional connectome during AS, which may contribute to a better understanding the network mechanisms of state bifurcations in epileptogenesis.

PMID: 23913255 [PubMed - indexed for MEDLINE]

Synchronous multiscale neuroimaging environment for critically sampled physiological analysis of brain function: hepta-scan concept.

Wed, 07/08/2015 - 18:00
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Synchronous multiscale neuroimaging environment for critically sampled physiological analysis of brain function: hepta-scan concept.

Brain Connect. 2014 Nov;4(9):677-89

Authors: Korhonen V, Hiltunen T, Myllylä T, Wang X, Kantola J, Nikkinen J, Zang YF, LeVan P, Kiviniemi V

Abstract
Functional connectivity of the resting-state networks of the brain is thought to be mediated by very-low-frequency fluctuations (VLFFs <0.1 Hz) in neuronal activity. However, vasomotor waves and cardiorespiratory pulsations influence indirect measures of brain function, such as the functional magnetic resonance imaging blood-oxygen-level-dependent (BOLD) signal. How strongly physiological oscillations correlate with spontaneous BOLD signals is not known, partially due to differences in the data-sampling rates of different methods. Recent ultrafast inverse imaging sequences, including magnetic resonance encephalography (MREG), enable critical sampling of these signals. In this study, we describe a multimodal concept, referred to as Hepta-scan, which incorporates synchronous MREG with scalp electroencephalography, near-infrared spectroscopy, noninvasive blood pressure, and anesthesia monitoring. Our preliminary results support the idea that, in the absence of aliased cardiorespiratory signals, VLFFs in the BOLD signal are affected by vasomotor and electrophysiological sources. Further, MREG signals showed a high correlation coefficient between the ventromedial default mode network (DMNvmpf) and electrophysiological signals, especially in the VLF range. Also, oxy- and deoxyhemoglobin and vasomotor waves were found to correlate with DMNvmpf. Intriguingly, usage of shorter time windows in these correlation measurements produced significantly (p<0.05) higher positive and negative correlation coefficients, suggesting temporal nonstationary behavior between the measurements. Focus on the VLF range strongly increased correlation strength.

PMID: 25131996 [PubMed - indexed for MEDLINE]

Altered regional homogeneity in rolandic epilepsy: a resting-state FMRI study.

Tue, 07/07/2015 - 17:00
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Altered regional homogeneity in rolandic epilepsy: a resting-state FMRI study.

Biomed Res Int. 2014;2014:960395

Authors: Tang YL, Ji GJ, Yu Y, Wang J, Wang ZJ, Zang YF, Liao W, Ding MP

Abstract
Children with rolandic epilepsy (RE) are often associated with cognitive deficits and behavioral problems. Findings from neurophysiological and neuroimaging studies in RE have now demonstrated dysfunction not only in rolandic focus, but also in distant neuronal circuits. Little is known, however, about whether there is distributed abnormal spontaneous brain activity in RE. Using resting-state functional magnetic resonance imaging (RS-fMRI), the present study aimed to determine whether children with RE show abnormal local synchronization during resting state and, if so, whether these changes could be associated with the behavioral/clinical characteristics of RE. Regional homogeneity (ReHo) in children with RE (n = 30) and healthy children (n = 20) was computed on resting-state functional MRI data. In comparison with healthy children, children with RE showed increased ReHo in the central, premotor, and prefrontal regions, while they showed decreased ReHo in bilateral orbitofrontal cortex and temporal pole. In addition, the ReHo value in the left orbitofrontal cortex negatively was corrected with performance intelligence quotient in the children with RE. The aberrant local synchronization, not strictly related to primary site of the typical rolandic focus, indicates the neuropathophysiological mechanism of RE. The study findings may shed new light on the understanding of neural correlation of neuropsychological deficiencies in the children with RE.

PMID: 25247197 [PubMed - indexed for MEDLINE]