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Resting-state functional connectivity dynamics in healthy aging: an approach through Network Change Point Detection.

Wed, 03/11/2020 - 21:17
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Resting-state functional connectivity dynamics in healthy aging: an approach through Network Change Point Detection.

Brain Connect. 2020 Mar 10;:

Authors: Mancho-Fora N, Montala-Flaquer M, Farras-Permamyer L, Bartres-Faz D, Vaque-Alcazar L, Pero-Cebollero M, Guardia-Olmos J

Abstract
The present study aims to assess the impact of age on the short-term temporal dynamics of the topological properties of the undirected and weighted whole-brain functional connectivity (FC) networks. We studied the association between the participant's age and the number of significant change points detected through Network Change Point Detection (NCPD) algorithm. Secondary, we defined as state the rs-fMRI subsequence between two significant change points, obtaining the FC network in each state and participant and characterized their network topological properties. The data comprises the rs-fMRI sequences of 114 healthy individuals combined from three different studies conducted at the Department of Medicine, School of Medicine and Health Sciences, University of Barcelona. Participants were healthy people in the absence of any pathology that could interfere with the scanning procedures, as well as any chronic illness that implied a short-lived situation. Topological properties of everyone's FC networks were characterized by their network strength, transitivity, characteristic path length and small-worldness, analysing the effect of age in those observed distributions. To that effect, we constructed a mixed linear model for each network topological property with age, state and state duration in the linear predictor. Several statistically significant relationships have been estimated between the indicators of the FC networks that show a certain regular pattern of change in the networks during the time of registration at resting fMRI paradigm. These dynamic changes seem to be related to the age of each group studied. Healthy aging could be characterized by FC dynamics patterns.

PMID: 32151149 [PubMed - as supplied by publisher]

Accurate prediction of individual subject identity and task, but not autism diagnosis, from functional connectomes.

Tue, 03/10/2020 - 21:14
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Accurate prediction of individual subject identity and task, but not autism diagnosis, from functional connectomes.

Hum Brain Mapp. 2020 Mar 09;:

Authors: Byrge L, Kennedy DP

Abstract
Despite enthusiasm about the potential for using fMRI-based functional connectomes in the development of biomarkers for autism spectrum disorder (ASD), the literature is full of negative findings-failures to distinguish ASD functional connectomes from those of typically developing controls (TD)-and positive findings that are inconsistent across studies. Here, we report on a new study designed to either better differentiate ASD from TD functional connectomes-or, alternatively, to refine our understanding of the factors underlying the current state of affairs. We scanned individuals with ASD and controls both at rest and while watching videos with social content. Using multiband fMRI across repeat sessions, we improved both data quantity and scanning duration by collecting up to 2 hr of data per individual. This is about 50 times the typical number of temporal samples per individual in ASD fcMRI studies. We obtained functional connectomes that were discriminable, allowing for near-perfect individual identification regardless of diagnosis, and equally reliable in both groups. However, contrary to what one might expect, we did not consistently or robustly observe in the ASD group either reductions in similarity to TD functional connectivity (FC) patterns or shared atypical FC patterns. Accordingly, FC-based predictions of diagnosis group achieved accuracy levels around chance. However, using the same approaches to predict scan type (rest vs. video) achieved near-perfect accuracy. Our findings suggest that neither the limitations of resting state as a "task," data resolution, data quantity, or scan duration can be considered solely responsible for failures to differentiate ASD from TD functional connectomes.

PMID: 32150312 [PubMed - as supplied by publisher]

Brain Functional Differences in Drug-Naive Major Depression with Anxiety Patients of Different Traditional Chinese Medicine Syndrome Patterns: A Resting-State fMRI Study.

Tue, 03/10/2020 - 21:14
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Brain Functional Differences in Drug-Naive Major Depression with Anxiety Patients of Different Traditional Chinese Medicine Syndrome Patterns: A Resting-State fMRI Study.

Evid Based Complement Alternat Med. 2020;2020:7504917

Authors: Du Y, Zhao J, Wang Y, Han Y, Deng L, Jia H, Zhou Y, Su J, Li L

Abstract
Major depressive disorder (MDD), especially combined with anxiety, has a high incidence and low detection rate in China. Literature has shown that patients under major depression with anxiety (MDA) are more likely to nominate a somatic, rather than psychological, symptom as their presenting complaint. In the theory of Traditional Chinese Medicine (TCM), clinical symptoms of MDD patients are mainly categorized into two different syndrome patterns: Deficiency and Excess. We intend to use resting-state functional magnetic resonance imaging (rs-fMRI) to investigate their brain functional differences and hopefully to find their brain function mechanism. For our research, 42 drug-naive MDA patients were divided into two groups (21 for Deficiency and 21 for Excess), with an additional 19 unaffected participants in the normal control (NC) group. We took Hamilton Depression Rating Scale (HAMD), Hamilton Anxiety Scale (HAMA), and brain fMRI scan for each group and analyzed the data. We first used Degree Centrality (DC) to map the functional differences in brain regions, utilized these regions as seed points, and used a seed-based functional connectivity (FC) analysis to identify the specific functional connection between groups. The Deficiency group was found to have higher HAMD scores, HAMA scores, and HAMD somatic factor than the Excess group. In the DC analysis, significant decreases were found in the right precuneus of both the Deficiency and Excess groups compared to the NC group. In the FC analysis, the right precuneus showed significant decreased network connectivity with the bilateral cuneus, as well as the right lingual gyrus in the Deficiency group when compared to the NC group and the Excess group. Through our research, it was found that precuneus dysfunction may have a relationship with MDA and Deficiency patients have more severe physical and emotional symptoms, and we realized that a larger sample size and multiple brain mode observations were needed in further research.

PMID: 32148551 [PubMed]

[Diffusion tensor imaging and resting-state functional magnetic resonance imaging in patients with delirium in intensive care unit].

Tue, 03/10/2020 - 21:14
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[Diffusion tensor imaging and resting-state functional magnetic resonance imaging in patients with delirium in intensive care unit].

Zhonghua Wei Zhong Bing Ji Jiu Yi Xue. 2020 Jan;32(1):88-93

Authors: Song R, Song G, Xie P, Duan H, Zhang T, Lu Y, Li M, Fu X

Abstract
OBJECTIVE: To analyze the brain function of patients with delirium in intensive care unit (ICU) using resting-state functional magnetic resonance imaging (fMRI), further analyze the structural changes in the brain using diffusion tensor imaging (DTI), and explore the correlations of brain function with structural changes in patients with delirium in ICU from a new perspective of functional imaging, provide visual evidence for the diagnosis of delirium.
METHODS: Patients with delirium admitted to ICU of the Affiliated Hospital of Zunyi Medical University from January 1st to December 31st in 2017 were enrolled as subjects. During the same period, the healthy volunteers who matched the gender, age and education level of the patients with delirium were enrolled as control group. The intensive care delirium screening checklist (ICDSC) scores within 24 hours after ICU admission were recorded. All the subjects were scanned by fMRI and DTI. The abnormal changes in resting-state brain function of the patients with delirium were evaluated by cerebral regional homogeneity (ReHo) data analysis. The DTI data were processed by the FSL software, and the fractional anisotropy (FA) and mean diffusivity (MD) of the brain were extracted, respectively, to evaluate the damage to brain structure. The values of ReHo, FA and MD were compared between the two groups. The ReHo value of brain region with reduced ReHo value of patients with delirium as compared with the healthy volunteers was extracted for Pearson correlation analysis with ICDSC scores.
RESULTS: A total of 22 patients with delirium were included. Seven patients who did not cooperate in the examination, used sedatives or had false images in scanning, were excluded. Finally, 15 patients were enrolled in the delirium group, and 15 healthy volunteers in the healthy control group. (1) No statistically significant difference was found in gender, age or education time between the two groups. ICDSC score of the delirium group was significantly higher than that of the healthy control group (6.07±1.28 vs. 1.07±0.88, P < 0.01). (2) fMRI scanning and analysis results: compared with the healthy control group, the ReHo values of the cerebellum, right hippocampus, striatum, midbrain and pons in the delirium group were significantly increased (all P < 0.05, AlphaSim correction), while the ReHo values of bilateral superior frontal gyrus, bilateral median frontal gyrus, left inferior frontal gyrus, temporal lobe and parietal lobe were significantly lowered (all P < 0.05, AlphaSim correction). Correlation analysis showed that the ReHo value of the left superior frontal gyrus was negatively correlated with ICDSC score in the patients with delirium (r = -0.794, P < 0.05), indicating that the changes in the functional area of the medial frontal gyrus was most closely related to delirium. (3) DTI scanning and analysis results: compared with the healthy control group, the FA values of the left cerebellum, bilateral frontal lobes, left temporal lobe, corpus callosum and left hippocampus in the delirium group were decreased significantly (all P < 0.05, AlphaSim correction), while the MD values of the medial frontal gyrus, right superior temporal gyrus, anterior cingulate gyrus, bilateral insular lobes and left caudate nucleus were enhanced significantly (all P < 0.05, AlphaSim correction), suggesting that the structural and functional damage was found in multiple brain regions in patients with delirium.
CONCLUSIONS: Multiple brain regions of patients with delirium present abnormal resting-state brain function. The abnormal resting-state brain function of the left superior frontal gyrus is closely related to the occurrence of delirium. Structural damage is found in multiple brain regions of patients with delirium. The structural changes in the frontal lobe, temporal lobe, corpus callosum, hippocampus and cerebellum and their abnormal functions can be used as preliminary imaging indexes for the diagnosis of delirium.

PMID: 32148238 [PubMed - in process]

Pregenual or subgenual anterior cingulate cortex as potential effective region for brain stimulation of depression.

Tue, 03/10/2020 - 21:14
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Pregenual or subgenual anterior cingulate cortex as potential effective region for brain stimulation of depression.

Brain Behav. 2020 Mar 08;:e01591

Authors: Jing Y, Zhao N, Deng XP, Feng ZJ, Huang GF, Meng M, Zang YF, Wang J

Abstract
BACKGROUND: The dorsolateral prefrontal cortex (DLPFC) is the standard stimulation target for the repetitive transcranial magnetic stimulation (rTMS) treatment of major depression disorder (MDD). A retrospective study by Fox and colleagues found that a more negative resting-state functional magnetic resonance imaging (RS-fMRI) functional connectivity (FC) between left DLPFC and the subgenual anterior cingulate cortex (sgACC) in a large group of healthy participants is associated with a better curative effects of rTMS in MDD, suggesting that the sgACC may be an effective region. However, a recent meta-analysis on RS-fMRI studies found that the pregenual ACC (pgACC), rather than the sgACC, of MDD patients showed increased local activity.
METHODS: We used the stimulation coordinates in the left DLPFC analyzed by Fox et al. to perform RS-fMRI FC between the stimulation targets obtained from previous rTMS MDD studies and the potential effective regions (sgACC and pgACC, respectively) on the RS-fMRI data from 88 heathy participants.
RESULTS: (a) Both the pgACC and the sgACC were negatively connected to the left DLPFC; (b) both FCs of sgACC-DLPFC and pgACC-DLPFC were more negative in responders than in nonresponders; and (c) the associations between DLPFC-sgACC functional connectivity and clinical efficacy were clustered around the midline sgACC.
CONCLUSIONS: Both the pgACC and the sgACC may be potential effective regions for rTMS on the left DLPFC for treatment of MDD. However, individualized ACC-DLPFC FC-based rTMS on depression should be performed in the future to test the pgACC or the sgACC as effective regions.

PMID: 32147973 [PubMed - as supplied by publisher]

Resting-state "physiological networks".

Sun, 03/08/2020 - 21:09
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Resting-state "physiological networks".

Neuroimage. 2020 Mar 04;:116707

Authors: Chen J, Lewis L, Chang C, Tian Q, Fultz N, Ohringer N, Rosen B, Polimeni J

Abstract
Slow changes in systemic brain physiology can elicit large fluctuations in fMRI time series, which manifest as structured spatial patterns of temporal correlations between distant brain regions. Here, we investigated whether such "physiological networks"-sets of segregated brain regions that exhibit similar responses following slow changes in systemic physiology-resemble patterns associated with large-scale networks typically attributed to remotely synchronized neuronal activity. By analyzing a large group of subjects from the 3T Human Connectome Project (HCP) database, we demonstrate brain-wide and noticeably heterogenous dynamics tightly coupled to either respiratory variation or heart rate changes. We show, using synthesized data generated from physiological recordings across subjects, that these physiologically-coupled fluctuations alone can produce networks that strongly resemble previously reported resting-state networks, suggesting that, in some cases, the "physiological networks" seem to mimic the neuronal networks. Further, we show that such physiologically-relevant connectivity estimates appear to dominate the overall connectivity observations in multiple HCP subjects, and that this apparent "physiological connectivity" cannot be removed by the use of a single nuisance regressor for the entire brain (such as global signal regression) due to the clear regional heterogeneity of the physiologically-coupled responses. Our results challenge previous notions that physiological confounds are either localized to large veins or globally coherent across the cortex, therefore emphasizing the necessity to consider potential physiological contributions in fMRI-based functional connectivity studies. The rich spatiotemporal patterns carried by such "physiological" dynamics also suggest great potential for clinical biomarkers that are complementary to large-scale neuronal networks.

PMID: 32145437 [PubMed - as supplied by publisher]

Sex differences in resting state network (RSN) functional connections with mild cognitive impairment (MCI) progression.

Sun, 03/08/2020 - 21:09
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Sex differences in resting state network (RSN) functional connections with mild cognitive impairment (MCI) progression.

Neurosci Lett. 2020 Mar 04;:134891

Authors: Zhao J, Ding X, Men G

Abstract
OBJECTIVE: Sex plays an important role in many diseases. The purpose of current study is to explore whether there are different lesion patterns in the RSN functional connections between males and females with MCI progression, and identify the differences in brain network changes due to sex.
METHODS: Resting state fMRI data included 37 normal controls (NC), 39 early MCI (EMCI) patients and 37 late MCI (LMCI) patients were collected, and network model based on graph theory was performed to compare the differences of brain network at different stages caused by sex from three aspects: functional connectivity between ROIs, intra-functional connectivity within RSN and inter-functional connectivity between RSN and white matter (WM).
RESULTS: Sex plays a role in the changes of RSN functional connectivity, including the default mode network (DMN), the sensory-motor network (SMN), the dorsal attention network (DAN) and the executive control network (CON). The female SMN is more vulnerable and the damage of functional connectivity between DAN and WM is more serious.
CONCLUSIONS: There are different lesion patterns in the RSN functional connections between males and females in the progression of MCI, which suggests that we should take full account of sex differences when conducting MCI progress studies and developing more effective biomarkers to promote the progress of cognitive impairment and dementia.

PMID: 32145308 [PubMed - as supplied by publisher]

On the Quality, Statistical Efficiency, and Safety of Simultaneously Recorded Multiband fMRI/EEG.

Sun, 03/08/2020 - 21:09
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On the Quality, Statistical Efficiency, and Safety of Simultaneously Recorded Multiband fMRI/EEG.

Brain Topogr. 2020 Mar 06;:

Authors: Chen JCC, Forsyth A, Dubowitz DJ, Muthukumaraswamy SD

Abstract
The recent development of multiband functional magnetic resonance imaging (MB-fMRI) allows for the reduction of sampling period by simultaneously exciting multiple slices-the number of which is referred to as the multiband factor. Simultaneously recorded electroencephalography (EEG)/MB-fMRI has yet to be validated for data quality against conventional single band (SB)-fMRI. Pilot scans were conducted on phantoms twice and on a healthy volunteer to ensure no heating effects. In the main study, two thermometer probes were attached to 16 healthy individuals (ages 20-39, 9 females) whilst they completed two sets of 16-min resting-state and two sets of 9-min n-back task scans-each set consisting of one MB4 and one SB pulse sequence. No heating effects were reported and thermometer data showed mean increases of < 1.0 °C. Minimal differences between the two scan types were found in EEG channel variance and spectra. Expected decreases in MB4-fMRI tSNR were observed. In n-back task scans, little to no differences were detected in both EEG source analyses and fMRI local analyses for mixed effects. Resting-state posterior cingulate cortex seed-based analyses of the default mode network along with EEG-informed fMRI analysis of the occipital alpha anticorrelation effect showed improved statistical and spatial sensitivity at lower scan durations. Using EEG/MB4-fMRI for n-back tasks provided no statistical advantages nor disadvantages. However, for studying the resting-state, MB4-fMRI potentially allows for reduced scanning durations for equivalent statistical significance to be obtained or alternatively, larger effect sizes for the same scanning duration. As such, simultaneous EEG/MB4-fMRI is a viable alternative to EEG/SB-fMRI.

PMID: 32144628 [PubMed - as supplied by publisher]

Microstates-based resting frontal alpha asymmetry approach for understanding affect and approach/withdrawal behavior.

Sun, 03/08/2020 - 21:09
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Microstates-based resting frontal alpha asymmetry approach for understanding affect and approach/withdrawal behavior.

Sci Rep. 2020 Mar 06;10(1):4228

Authors: Kaur A, Chinnadurai V, Chaujar R

Abstract
The role of resting frontal alpha-asymmetry in explaining neural-mechanisms of affect and approach/withdrawal behavior is still debatable. The present study explores the ability of the quasi-stable resting EEG asymmetry information and the associated neurovascular synchronization/desynchronization in bringing more insight into the understanding of neural-mechanisms of affect and approach/withdrawal behavior. For this purpose, a novel frontal alpha-asymmetry based on microstates, that assess quasi-stable EEG scalp topography information, is proposed and compared against standard frontal-asymmetry. Both proposed and standard frontal alpha-asymmetries were estimated from thirty-nine healthy volunteers resting-EEG simultaneously acquired with resting-fMRI. Further, neurovascular mechanisms of these asymmetry measures were estimated through EEG-informed fMRI. Subsequently, the Hemodynamic Lateralization Index (HLI) of the neural-underpinnings of both asymmetry measures was assessed. Finally, the robust correlation of both asymmetry-measures and their HLI's with PANAS, BIS/BAS was carried out. The standard resting frontal-asymmetry and its HLI yielded no significant correlation with any psychological-measures. However, the microstate resting frontal-asymmetry correlated significantly with negative affect and its neural underpinning's HLI significantly correlated with Positive/Negative affect and BIS/BAS measures. Finally, alpha-BOLD desynchronization was observed in neural-underpinning whose HLI correlated significantly with negative affect and BIS. Hence, the proposed resting microstate-frontal asymmetry better assesses the neural-mechanisms of affect, approach/withdrawal behavior.

PMID: 32144318 [PubMed - as supplied by publisher]

Dissociating the neural correlates of the sociality and plausibility effects in simple conceptual combination.

Sat, 03/07/2020 - 21:05
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Dissociating the neural correlates of the sociality and plausibility effects in simple conceptual combination.

Brain Struct Funct. 2020 Mar 05;:

Authors: Lin N, Xu Y, Yang H, Zhang G, Zhang M, Wang S, Hua H, Li X

Abstract
Neuroimaging studies have indicated that a brain network distributed in the supramodal cortical regions of the frontal, temporal, and parietal lobes plays a central role in conceptual processing. The activation of this network is modulated by two orthogonal dimensions in conceptual processing-the semantic features of individual concepts and the meaningfulness of conceptual combinations-but it remains unclear how the network is functionally organized along these two dimensions. In this fMRI study, we focused on two specific factors, i.e. the social semantic richness of words and the semantic plausibility of word combinations, along the two dimensions. In literature, the distributions of the effects of the two factors are very similar, but have not been rigorously compared in one study. We orthogonally manipulated the two factors in a phrase comprehension task and found a clear dissociation between their effects. The combination of these results with our previous findings reveals three adjacently distributed subnetworks of the supramodal semantic network, associated with the sociality effect, imageability effect, and semantic plausibility effect, respectively. Further analysis of the resting-state functional connectivity data indicated that the functional dissociation among the three subnetworks is associated with their underlying intrinsic connectivity structures.

PMID: 32140848 [PubMed - as supplied by publisher]

Feature Selection and Combination of Information in the Functional Brain Connectome for Discrimination of Mild Cognitive Impairment and Analyses of Altered Brain Patterns.

Sat, 03/07/2020 - 21:05
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Feature Selection and Combination of Information in the Functional Brain Connectome for Discrimination of Mild Cognitive Impairment and Analyses of Altered Brain Patterns.

Front Aging Neurosci. 2020;12:28

Authors: Xu X, Li W, Mei J, Tao M, Wang X, Zhao Q, Liang X, Wu W, Ding D, Wang P

Abstract
Mild cognitive impairment (MCI) is often considered a critical time window for predicting early conversion to Alzheimer's disease (AD). Brain functional connectome data (i.e., functional connections, global and nodal graph metrics) based on resting-state functional magnetic resonance imaging (rs-fMRI) provides numerous information about brain networks and has been used to discriminate normal controls (NCs) from subjects with MCI. In this paper, Student's t-tests and group-least absolute shrinkage and selection operator (group-LASSO) were used to extract functional connections with significant differences and the most discriminative network nodes, respectively. Based on group-LASSO, the middle temporal, inferior temporal, lingual, posterior cingulate, and middle frontal gyri were the most predominant brain regions for nodal observation in MCI patients. Nodal graph metrics (within-module degree, participation coefficient, and degree centrality) showed the maximum discriminative ability. To effectively combine the multipattern information, we employed the multiple kernel learning support vector machine (MKL-SVM). Combined with functional connectome information, the MKL-SVM achieved a good classification performance (area under the receiving operating characteristic curve = 0.9728). Additionally, the altered brain connectome pattern revealed that functional connectivity was generally decreased in the whole-brain network, whereas graph theory topological attributes of some special nodes in the brain network were increased in MCI patients. Our findings demonstrate that optimal feature selection and combination of all connectome features (i.e., functional connections, global and nodal graph metrics) can achieve good performance in discriminating NCs from MCI subjects. Thus, the combination of functional connections and global and nodal graph metrics of brain networks can predict the occurrence of MCI and contribute to the early clinical diagnosis of AD.

PMID: 32140102 [PubMed]

Indexing brain state-dependent pupil dynamics with simultaneous fMRI and optical fiber calcium recording.

Sat, 03/07/2020 - 21:05
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Indexing brain state-dependent pupil dynamics with simultaneous fMRI and optical fiber calcium recording.

Proc Natl Acad Sci U S A. 2020 Mar 05;:

Authors: Pais-Roldán P, Takahashi K, Sobczak F, Chen Y, Zhao X, Zeng H, Jiang Y, Yu X

Abstract
Pupillometry, a noninvasive measure of arousal, complements human functional MRI (fMRI) to detect periods of variable cognitive processing and identify networks that relate to particular attentional states. Even under anesthesia, pupil dynamics correlate with brain-state fluctuations, and extended dilations mark the transition to more arousable states. However, cross-scale neuronal activation patterns are seldom linked to brain state-dependent pupil dynamics. Here, we complemented resting-state fMRI in rats with cortical calcium recording (GCaMP-mediated) and pupillometry to tackle the linkage between brain-state changes and neural dynamics across different scales. This multimodal platform allowed us to identify a global brain network that covaried with pupil size, which served to generate an index indicative of the brain-state fluctuation during anesthesia. Besides, a specific correlation pattern was detected in the brainstem, at a location consistent with noradrenergic cell group 5 (A5), which appeared to be dependent on the coupling between different frequencies of cortical activity, possibly further indicating particular brain-state dynamics. The multimodal fMRI combining concurrent calcium recordings and pupillometry enables tracking brain state-dependent pupil dynamics and identifying unique cross-scale neuronal dynamic patterns under anesthesia.

PMID: 32139609 [PubMed - as supplied by publisher]

Altered resting-state thalamo-occipital functional connectivity is associated with cognition in isolated rapid eye movement sleep behavior disorder.

Sat, 03/07/2020 - 09:04
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Altered resting-state thalamo-occipital functional connectivity is associated with cognition in isolated rapid eye movement sleep behavior disorder.

Sleep Med. 2020 Jan 18;69:198-203

Authors: Byun JI, Kim HW, Kang H, Cha KS, Sunwoo JS, Shin JW, Moon J, Lee ST, Jung KH, Chu K, Kim M, Shin WC, Lee DS, Schenck CH, Lee SK, Jung KY

Abstract
OBJECTIVE: Isolated rapid eye movement sleep behavior disorder (iRBD) patients are at risk of cognitive impairments, however the underlying mechanism is still unclear. This study aimed to evaluate thalamo-cortical functional connectivity (FC) using resting-state functional magnetic resonance imaging (fMRI) and its correlation with cognitive dysfunction in patients with iRBD.
METHODS: A total 37 polysomnographies (PSGs) confirmed iRBD patients and 15 age-sex matched controls underwent resting-state fMRI and comprehensive neuropsychological assessment. Thalamo-cortical FC was evaluated by using seed-to voxel analysis and was compared between the iRBD and controls. Correlation between the average value of significant clusters and cognitive function scores in iRBD were calculated.
RESULTS: Compared to the control subjects, patients with iRBD patients showed cognitive decline in word list recognition (p = 0.016), and constructional recall (p = 0.044). The FC analysis showed increased FC between the left thalamus and occipital regions including the right cuneal cortex, left fusiform gyrus and lingual gyrus (cluster level p < 0.05, corrected for false discovery rate). The averaged thalamo-fusiform FC value positively correlated with word list recognition after adjusting for age and sex (adjusted r = 0.347, p = 0.041).
CONCLUSION: Thalamic resting state FC is altered in iRBD patients and is associated with the cognitive function. Enhancement of the thalamo-occipital FC may reflect a compensatory mechanism for cognitive impairment in iRBD.

PMID: 32135454 [PubMed - as supplied by publisher]

Brain Resting-State Network Alterations Associated With Crohn's Disease.

Sat, 03/07/2020 - 09:04
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Brain Resting-State Network Alterations Associated With Crohn's Disease.

Front Neurol. 2020;11:48

Authors: Kornelsen J, Wilson A, Labus JS, Witges K, Mayer EA, Bernstein CN

Abstract
Inflammatory bowel disease (IBD) is a chronic disease that is associated with aspects of brain anatomy and activity. In this preliminary MRI study, we investigated differences in brain structure and in functional connectivity (FC) of brain regions in 35 participants with Crohn's disease (CD) and 21 healthy controls (HC). Voxel-based morphometry (VBM) analysis was performed to contrast CD and HC structural images. Region of interest (ROI) analyses were run to assess FC for resting-state network nodes. Independent component analysis (ICA) identified whole brain differences in FC associated with resting-state networks. Though no structural differences were found, ROI analyses showed increased FC between the frontoparietal (FP) network and salience network (SN), and decreased FC between nodes of the default mode network (DMN). ICA results revealed changes involving cerebellar (CER), visual (VIS), and SN components. Differences in FC associated with sex were observed for both ROI analysis and ICA. Taken together, these changes are consistent with an influence of CD on the brain and serve to direct future research hypotheses.

PMID: 32132964 [PubMed]

Using the General Linear Model to Improve Performance in fNIRS Single Trial Analysis and Classification: A Perspective.

Sat, 03/07/2020 - 09:04
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Using the General Linear Model to Improve Performance in fNIRS Single Trial Analysis and Classification: A Perspective.

Front Hum Neurosci. 2020;14:30

Authors: von Lühmann A, Ortega-Martinez A, Boas DA, Yücel MA

Abstract
Within a decade, single trial analysis of functional Near Infrared Spectroscopy (fNIRS) signals has gained significant momentum, and fNIRS joined the set of modalities frequently used for active and passive Brain Computer Interfaces (BCI). A great variety of methods for feature extraction and classification have been explored using state-of-the-art Machine Learning methods. In contrast, signal preprocessing and cleaning pipelines for fNIRS often follow simple recipes and so far rarely incorporate the available state-of-the-art in adjacent fields. In neuroscience, where fMRI and fNIRS are established neuroimaging tools, evoked hemodynamic brain activity is typically estimated across multiple trials using a General Linear Model (GLM). With the help of the GLM, subject, channel, and task specific evoked hemodynamic responses are estimated, and the evoked brain activity is more robustly separated from systemic physiological interference using independent measures of nuisance regressors, such as short-separation fNIRS measurements. When correctly applied in single trial analysis, e.g., in BCI, this approach can significantly enhance contrast to noise ratio of the brain signal, improve feature separability and ultimately lead to better classification accuracy. In this manuscript, we provide a brief introduction into the GLM and show how to incorporate it into a typical BCI preprocessing pipeline and cross-validation. Using a resting state fNIRS data set augmented with synthetic hemodynamic responses that provide ground truth brain activity, we compare the quality of commonly used fNIRS features for BCI that are extracted from (1) conventionally preprocessed signals, and (2) signals preprocessed with the GLM and physiological nuisance regressors. We show that the GLM-based approach can provide better single trial estimates of brain activity as well as a new feature type, i.e., the weight of the individual and channel-specific hemodynamic response function (HRF) regressor. The improved estimates yield features with higher separability, that significantly enhance accuracy in a binary classification task when compared to conventional preprocessing-on average +7.4% across subjects and feature types. We propose to adapt this well-established approach from neuroscience to the domain of single-trial analysis and preprocessing wherever the classification of evoked brain activity is of concern, for instance in BCI.

PMID: 32132909 [PubMed]

Intersubject consistent dynamic connectivity during natural vision revealed by functional MRI.

Thu, 03/05/2020 - 21:02
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Intersubject consistent dynamic connectivity during natural vision revealed by functional MRI.

Neuroimage. 2020 Mar 01;:116698

Authors: Di X, Biswal BB

Abstract
The functional communications between brain regions are thought to be dynamic. However, it is usually difficult to elucidate whether the observed dynamic connectivity is functionally meaningful or simply due to noise during unconstrained task conditions such as resting-state. During naturalistic conditions, such as watching a movie, it has been shown that local brain activities, e.g. in the visual cortex, are consistent across subjects. Following similar logic, we propose to study intersubject correlations of the time courses of dynamic connectivity during naturalistic conditions to extract functionally meaningful dynamic connectivity patterns. We analyzed a functional MRI (fMRI) dataset when the subjects watched a short animated movie. We calculated dynamic connectivity by using sliding window technique, and quantified the intersubject correlations of the time courses of dynamic connectivity. Although the time courses of dynamic connectivity are thought to be noisier than the original signals, we found similar level of intersubject correlations of dynamic connectivity to those of regional activity. Most importantly, highly consistent dynamic connectivity could occur between regions that did not show high intersubject correlations of regional activity, and between regions with little stable functional connectivity. The analysis highlighted higher order brain regions such as the default mode network that dynamically interacted with posterior visual regions during the movie watching, which may be associated with the understanding of the movie.

PMID: 32130972 [PubMed - as supplied by publisher]

Elevation of intracranial pressure affects the relationship between hemoglobin concentration and neuronal activation in human somatosensory cortex.

Thu, 03/05/2020 - 21:02
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Elevation of intracranial pressure affects the relationship between hemoglobin concentration and neuronal activation in human somatosensory cortex.

Hum Brain Mapp. 2020 Mar 04;:

Authors: Thranitz J, Knauth M, Heldmann M, Küchler J, Münte TF, Royl G

Abstract
During neuronal activation, a local decrease of deoxygenated hemoglobin concentration (deoxy-Hb) occurs which is the basis of functional brain imaging with blood oxygenation level dependent functional magnetic resonance imaging (BOLD-fMRI). Elevated intracranial pressure (eICP) has been shown to impair functional deoxy-Hb changes. This study investigated this effect and its relation to the underlying neuronal activity in the human primary somatosensory cortex (SI). Functional near-infrared spectroscopy (fNIRS) during somatosensory evoked potentials (SEP) monitoring was performed on 75 subjects during conditions of median nerve stimulation (MNS) and resting state, combined with normal breathing (NB) and eICP by escalating breathing maneuvers (breath holding [BH], Valsalva maneuver with 15 mmHg [V15] and 35 mmHg expiratory pressure [V35]). During NB, fNIRS revealed a typical oxygenated hemoglobin concentration (oxy-Hb) increase with deoxy-Hb decrease during MNS enabling SI brain mapping. Breathing maneuvers associated eICP produced a known global change of oxy-Hb and deoxy-Hb with and without MNS. When subtracting measurements during resting state from measurements during MNS, neither functional oxy-Hb nor deoxy-Hb changes could be recovered while SEPs remained unchanged. In conclusion, Valsalva-induced eICP prevents oxy-Hb and deoxy-Hb changes during neuronal activation in SI. This finding raises questions on the validity of oxy-Hb- and deoxy-Hb-based brain imaging (e.g., BOLD-fMRI) during eICP.

PMID: 32128949 [PubMed - as supplied by publisher]

The developmental trajectory of fronto-temporoparietal connectivity as a proxy of the default mode network: a longitudinal fNIRS investigation.

Thu, 03/05/2020 - 21:02
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The developmental trajectory of fronto-temporoparietal connectivity as a proxy of the default mode network: a longitudinal fNIRS investigation.

Hum Brain Mapp. 2020 Mar 04;:

Authors: Bulgarelli C, de Klerk CCJM, Richards JE, Southgate V, Hamilton A, Blasi A

Abstract
The default mode network (DMN) is a network of brain regions that is activated while we are not engaged in any particular task. While there is a large volume of research documenting functional connectivity within the DMN in adults, knowledge of the development of this network is still limited. There is some evidence for a gradual increase in the functional connections within the DMN during the first 2 years of life, in contrast to other functional resting-state networks that support primary sensorimotor functions, which are online from very early in life. Previous studies that investigated the development of the DMN acquired data from sleeping infants using fMRI. However, sleep stages are known to affect functional connectivity. In the current longitudinal study, fNIRS was used to measure spontaneous fluctuations in connectivity within fronto-temporoparietal areas-as a proxy for the DMN-in awake participants every 6 months from 11 months till 36 months. This study validates a method for recording resting-state data from awake infants, and presents a data analysis pipeline for the investigation of functional connections with infant fNIRS data, which will be beneficial for researchers in this field. A gradual development of fronto-temporoparietal connectivity was found, supporting the idea that the DMN develops over the first years of life. Functional connectivity reached its maximum peak at about 24 months, which is consistent with previous findings showing that, by 2 years of age, DMN connectivity is similar to that observed in adults.

PMID: 32128946 [PubMed - as supplied by publisher]

Age-related change of auditory functional connectivity in Human Connectome Project data and tinnitus patients.

Thu, 03/05/2020 - 21:02
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Age-related change of auditory functional connectivity in Human Connectome Project data and tinnitus patients.

Laryngoscope Investig Otolaryngol. 2020 Feb;5(1):132-136

Authors: Minami SB, Oishi N, Watabe T, Wasano K, Ogawa K

Abstract
Background: We reported that tinnitus patients showed reduced levels of auditory functional connectivity (FC) in comparison with normal hearing control subjects, and that we succeeded in objective diagnosis of tinnitus with 86% sensitivity and 74% specificity by focusing only on auditory-related FC. However, the age-related change of auditory FC is not clarified. In this study, we examine age-related change of the auditory FC using the database of Human Connectome Project (HCP) and compared with our database of tinnitus patients.
Method: From the HCP database HCP Lifespan Pilot project, we studied five age groups, 8 to 9 years old, 14 to 15, 25 to 35, 45 to 55, and 65 to 75. We also applied our tinnitus patients' resting-state functional magnetic resonance imaging (fMRI) database, which is divided into three generations; 20 to 40 years old, 40 to 60, and 60 to 80 to compare with the HCP database. The resting state fMRI analyses were performed using the CONN toolbox version 18. As auditory-related regions, Heschl's gyrus, planum temporale, planum polare, operculum, insular cortex, and superior temporal gyrus were set as the regions of interest from our previous reports.
Result: Auditory FC is strongest among adolescents and reduces with age. But the auditory FC of tinnitus patients were significantly less than those of HCP data in each generation.
Conclusion: Although auditory FC decreases with age, tinnitus patients have less auditory FC compared with age-matched controls. The age-matched cutoff values are necessary for an objective diagnosis of tinnitus with resting state fMRI.

PMID: 32128439 [PubMed]

The participation of basolateral amygdala in the efficacy of acupuncture with deqi treating for functional dyspepsia.

Wed, 03/04/2020 - 21:01
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The participation of basolateral amygdala in the efficacy of acupuncture with deqi treating for functional dyspepsia.

Brain Imaging Behav. 2020 Mar 03;:

Authors: Sun R, He Z, Ma P, Yin S, Yin T, Liu X, Lu J, Qu Y, Zhang T, Huang L, Suo X, Lei D, Gong Q, Liang F, Zeng F

Abstract
Deqi is taken as an indispensable requirement to achieve acupuncture efficacy. This study aimed to explore the central influence of deqi on the efficacy of acupuncture for functional dyspepsia (FD). 70 FD patients were randomized to receive 20 sessions' acupuncture treatment with (n = 35) and without deqi (n = 35). In each group, 25 FD patients randomly selected underwent functional magnetic resonance imaging (fMRI) scans before and after treatment. After group re-division according to deqi response, changes of amygdala subregions-based resting-state functional connectivity (rsFC) were compared between the acupuncture with and without obvious deqi group. The clinical changes of the Nepean Dyspepsia Symptom Index (NDSI) measuring FD symptoms were also used to further assess the correlation with amygdala subregions rsFC in FD patients. The decrease in the NDSI scores (pre-pos) in the obvious deqi group was significantly greater than that in the acupuncture without obvious deqi group (p < 0.05). Compared to the without obvious deqi group, the obvious deqi group showed significantly decreased the left basolateral amygdala (BLA) rsFC with bilateral insular (INS), putamen and middle/posterior cingulate cortex (MCC/PCC), right pallidum and hippocampus (HIPP) after treatment. The changed NDSI scores(pre-post) of all 41 FD patients was significantly positively correlated with their Fisher's transformed z value of the left BLA rsFC with left INS (r = 0.376, FDR corrected p = 0.015), and rsFC with right HIPP (r = 0.394, FDR corrected p = 0.015). The changed NDSI scores(pre-post) of the obvious deqi group was significantly negatively correlated with their Fisher's transformed z value of the right centromedial amygdala (CMA) rsFC with left medial prefrontal cortex (mPFC) (r = -0.463, p = 0.035). The results tested the hypothesis that the advantage of deqi on efficacy is related to affecting the BLA and CMA rsFC. It suggested that deqi might influence the abnormal rsFC within the salience network (SN), and participate in the adaptive modulation of disrupted relationship between the SN and default mode network (DMN).

PMID: 32125619 [PubMed - as supplied by publisher]