New resting-state fMRI related studies at PubMed

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Comparison of heritability estimates on resting state fMRI connectivity phenotypes using the ENIGMA analysis pipeline.

Sat, 07/28/2018 - 13:40

Comparison of heritability estimates on resting state fMRI connectivity phenotypes using the ENIGMA analysis pipeline.

Hum Brain Mapp. 2018 Jul 27;:

Authors: Adhikari BM, Jahanshad N, Shukla D, Glahn DC, Blangero J, Fox PT, Reynolds RC, Cox RW, Fieremans E, Veraart J, Novikov DS, Nichols TE, Hong LE, Thompson PM, Kochunov P

Abstract
We measured and compared heritability estimates for measures of functional brain connectivity extracted using the Enhancing Neuroimaging Genetics through Meta-Analysis (ENIGMA) rsfMRI analysis pipeline in two cohorts: the genetics of brain structure (GOBS) cohort and the HCP (the Human Connectome Project) cohort. These two cohorts were assessed using conventional (GOBS) and advanced (HCP) rsfMRI protocols, offering a test case for harmonization of rsfMRI phenotypes, and to determine measures that show consistent heritability for in-depth genome-wide analysis. The GOBS cohort consisted of 334 Mexican-American individuals (124M/210F, average age = 47.9 ± 13.2 years) from 29 extended pedigrees (average family size = 9 people; range 5-32). The GOBS rsfMRI data was collected using a 7.5-min acquisition sequence (spatial resolution = 1.72 × 1.72 × 3 mm3 ). The HCP cohort consisted of 518 twins and family members (240M/278F; average age = 28.7 ± 3.7 years). rsfMRI data was collected using 28.8-min sequence (spatial resolution = 2 × 2 × 2 mm3 ). We used the single-modality ENIGMA rsfMRI preprocessing pipeline to estimate heritability values for measures from eight major functional networks, using (1) seed-based connectivity and (2) dual regression approaches. We observed significant heritability (h2 = 0.2-0.4, p < .05) for functional connections from seven networks across both cohorts, with a significant positive correlation between heritability estimates across two cohorts. The similarity in heritability estimates for resting state connectivity measurements suggests that the additive genetic contribution to functional connectivity is robustly detectable across populations and imaging acquisition parameters. The overarching genetic influence, and means to consistently detect it, provides an opportunity to define a common genetic search space for future gene discovery studies.

PMID: 30052318 [PubMed - as supplied by publisher]

Reorganization of cerebro-cerebellar circuit in patients with left hemispheric gliomas involving language network: A combined structural and resting-state functional MRI study.

Sat, 07/28/2018 - 13:40

Reorganization of cerebro-cerebellar circuit in patients with left hemispheric gliomas involving language network: A combined structural and resting-state functional MRI study.

Hum Brain Mapp. 2018 Jul 27;:

Authors: Zhang N, Xia M, Qiu T, Wang X, Lin CP, Guo Q, Lu J, Wu Q, Zhuang D, Yu Z, Gong F, Farrukh Hameed NU, He Y, Wu J, Zhou L

Abstract
The role of cerebellum and cerebro-cerebellar system in neural plasticity induced by cerebral gliomas involving language network has long been ignored. Moreover, whether or not the process of reorganization is different in glioma patients with different growth kinetics remains largely unknown. To address this issue, we utilized preoperative structural and resting-state functional MRI data of 78 patients with left cerebral gliomas involving language network areas, including 46 patients with low-grade glioma (LGG, WHO grade II), 32 with high-grade glioma (HGG, WHO grade III/IV), and 44 healthy controls. Spontaneous brain activity, resting-state functional connectivity and gray matter volume alterations of the cerebellum were examined. We found that both LGG and HGG patients exhibited bidirectional alteration of brain activity in language-related cerebellar areas. Brain activity in areas with increased alteration was significantly correlated with the language and MMSE scores. Structurally, LGG patients exhibited greater gray matter volume in regions with increased brain activity, suggesting a structure-function coupled alteration in cerebellum. Furthermore, we observed that cerebellar regions with decreased brain activity exhibited increased functional connectivity with contralesional cerebro-cerebellar system in LGG patients. Together, our findings provide empirical evidence for a vital role of cerebellum and cerebro-cerebellar circuit in neural plasticity following lesional damage to cerebral language network. Moreover, we highlight the possible different reorganizational mechanisms of brain functional connectivity underlying different levels of behavioral impairments in LGG and HGG patients.

PMID: 30052314 [PubMed - as supplied by publisher]

Resting-state functional connectivity of subcortical locomotor centers explains variance in walking capacity.

Sat, 07/28/2018 - 13:40

Resting-state functional connectivity of subcortical locomotor centers explains variance in walking capacity.

Hum Brain Mapp. 2018 Jul 27;:

Authors: Boyne P, Maloney T, DiFrancesco M, Fox MD, Awosika O, Aggarwal P, Woeste J, Jaroch L, Braswell D, Vannest J

Abstract
Walking capacity influences the quality of life and disability in normal aging and neurological disease, but the neural correlates remain unclear and subcortical locomotor regions identified in animals have been more challenging to assess in humans. Here we test whether resting-state functional MRI connectivity (rsFC) of midbrain and cerebellar locomotor regions (MLR and CLR) is associated with walking capacity among healthy adults. Using phenotypic and MRI data from the Nathan Kline Institute Rockland Sample (n =119, age 18-85), the association between walking capacity (6-min walk test distance) and rsFC was calculated from subcortical locomotor regions to 81 other gait-related regions of interest across the brain. Additional analyses assessed the independence and specificity of the results. Walking capacity was associated with higher rsFC between the MLR and superior frontal gyrus adjacent to the anterior cingulate cortex, higher rsFC between the MLR and paravermal cerebellum, and lower rsFC between the CLR and primary motor cortex foot area. These rsFC correlates were more strongly associated with walking capacity than phenotypic variables such as age, and together explained 25% of the variance in walking capacity. Results were specific to locomotor regions compared with the other brain regions. The rsFC of locomotor centers correlates with walking capacity among healthy adults. These locomotion-related biomarkers may prove useful in future work aimed at helping patients with reduced walking capacity.

PMID: 30052301 [PubMed - as supplied by publisher]

The Role of Neuroimaging in the Diagnosis and Treatment of Depressive Disorder: A Recent Review.

Sat, 07/28/2018 - 13:40

The Role of Neuroimaging in the Diagnosis and Treatment of Depressive Disorder: A Recent Review.

Curr Pharm Des. 2018 Jul 26;:

Authors: Song T, Han X, Du L, Che J, Liu J, Shi S, Fu C, Gao W, Lu J, Ma G

Abstract
Depression is a mental disorder with serious negative health outcomes. Its main clinical manifestations are depressed mood, slow thinking, loss of interest, and lack of energy. The rising incidence of depression has a major impact on patients and their families and imposes a substantial burden on society. With the rapid development of imaging technology in recent years, researchers have studied depression from different perspectives, including molecular, functional, and structural imaging. Many studies have revealed changes in structure, function, and metabolism in various brain regions in patients with depressive disorder. In this review, we summarize relevant studies of depression, including investigations using structural magnetic resonance imaging (MRI), functional MRI (task-state fMRI and resting-state fMRI), diffusion tensor imaging (DTI), magnetic resonance spectroscopy (MRS), brain network and molecular imaging (positron emission tomography [PET] and single photon emission computed tomography [SPECT]), which have contributed to our understanding of the etiology, neuropathology, and pathogenesis of depressive disorder.

PMID: 30051778 [PubMed - as supplied by publisher]

Effects of the 2-Repeat Allele of the DRD4 Gene on Neural Networks Associated With the Prefrontal Cortex in Children With ADHD.

Sat, 07/28/2018 - 13:40
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Effects of the 2-Repeat Allele of the DRD4 Gene on Neural Networks Associated With the Prefrontal Cortex in Children With ADHD.

Front Hum Neurosci. 2018;12:279

Authors: Qian A, Tao J, Wang X, Liu H, Ji L, Yang C, Ye Q, Chen C, Li J, Cheng J, Wang M, Zhao K

Abstract
Objective: Genetic variation, especially polymorphism of the dopamine D4 receptor gene (DRD4), has been linked to deficits in self-regulation and executive functions and to attention deficit hyperactivity disorder (ADHD), and is related to the structural and functional integrity of the default mode network (DMN), the executive control network (ECN) and the sensorimotor network (SMN). The aim of this study was to explore the effects of the 2-repeat allele of the DRD4 gene on brain network connectivity and behaviors in children with ADHD. Methods: Using independent component analysis (ICA) and dimension analyses, we examined resting-state functional magnetic resonance imaging (fMRI) data obtained from 52 Asian medicine-naive children with ADHD (33 2-repeat absent and 19 2-repeat present). Results: We found that individuals with 2-repeat absent demonstrated increased within-network connectivity in the right precuneus of the DMN, the right middle frontal gyrus (MFG) of the SMN compared with individuals with 2-repeat present. Within the ECN, 2-repeat absent showed decreased within-network connectivity in the left inferior frontal gyrus (IFG) and the left anterior cingulate cortex. A deeper study found that connectivity strength of the left IFG was directly proportional to the Stroop reaction time in 2-repeat absent group, and as well as the right MFG in 2-repeat present group. Conclusion: Polymorphisms of the DRD4 gene, specifically 2-repeat allele, had effects on the ECN, the SMN and the DMN, especially in the prefrontal cortex (PFC) circles. ADHD children with DRD4 2-repeat allele have aberrant resting-state within-network connectivity patterns in the left IFG and the right MFG related to dysfunction in inattention symptom. This study provided novel insights into the neural mechanisms underlying the effects of DRD4 2-repeat allele on ADHD.

PMID: 30050420 [PubMed]

Functional Connectivity of the Caudate in Schizophrenia Evaluated with Simultaneous Resting-State Functional MRI and Electroencephalography Recordings.

Fri, 07/27/2018 - 12:40

Functional Connectivity of the Caudate in Schizophrenia Evaluated with Simultaneous Resting-State Functional MRI and Electroencephalography Recordings.

Neuropsychobiology. 2018 Jul 26;:1-11

Authors: Kirino E, Tanaka S, Fukuta M, Inami R, Inoue R, Aoki S

Abstract
BACKGROUND: Aberrant functional connectivity (FC) is increasingly implicated in the clinical phenomenology of schizophrenia. This study focused on the FC of the cortico-striatal network, which is thought to be disrupted in schizophrenia and to contribute to its clinical manifestations.
METHODS: We used simultaneous resting-state functional magnetic resonance imaging (rsfMRI) and electroencephalography (EEG) recordings to investigate FC in patients with schizophrenia. The study included 20 patients with schizophrenia and 20 healthy controls (HCs). Simultaneously recorded rsfMRI and EEG data were collected with an MR-compatible amplifier, and rsfMRI data were analyzed with the CONN toolbox to calculate FC. The study focused on the caudate, which was defined as the seed. We also performed between-group comparisons of standardized low-resolution electromagnetic tomography intracortical lagged coherence for each EEG frequency band.
RESULTS: Compared to HCs, patients with schizophrenia showed enhanced FC between the caudate nucleus and the posterior cingulate cortex, temporal, and occipital regions on rsfMRI. It is thus possible that HCs have negative FC between these regions, whereas patients with schizophrenia have non-negative FC. The EEG results showed no significant differences in oscillations or in FC between the groups in any frequency band in any region.
CONCLUSIONS: Increased FC in the caudate may represent aberrant between-network FC resulting from the disruption of segregation between networks.

PMID: 30048962 [PubMed - as supplied by publisher]

Frequency-specific alterations in the amplitude and synchronization of resting-state spontaneous low-frequency oscillations in benign childhood epilepsy with centrotemporal spikes.

Fri, 07/27/2018 - 12:40

Frequency-specific alterations in the amplitude and synchronization of resting-state spontaneous low-frequency oscillations in benign childhood epilepsy with centrotemporal spikes.

Epilepsy Res. 2018 Jul 19;145:178-184

Authors: Tan G, Xiao F, Chen S, Wang H, Chen D, Zhu L, Xu D, Zhou D, Liu L

Abstract
OBJECTIVES: Spontaneous low-frequency oscillations in different frequency bands have diverse physiological meanings. The amplitude of low-frequency fluctuation (ALFF) and functional connectivity (FC) in different frequency bands in Benign Childhood Epilepsy with Centrotemporal Spikes (BECTS) are unknown and worth exploring.
METHOD: Resting-state functional magnetic resonance imaging data were collected in 51 drug-naïve BECTS patients and 76 healthy controls. The ALFF was calculated for the typical (0.01 - 0.08 Hz), slow-5 (0.01-0.027 Hz), slow-4 (0.027-0.073 Hz), and slow-3 (0.073-0.198 Hz) frequency bands. The bilateral precuneus/posterior cingulate cortex (PCU/PCC) showed a common alteration of ALFF in different frequency bands, and was selected as the seed for calculating FC per voxel.
RESULTS: In the typical band, BECTS patients showed increased ALFF in the left rolandic operculum and the right pre/postcentral gyrus, and decreased ALFF in the bilateral PCU/PCC, some of which were shared by the slow-5, slow-4, and slow-3 bands. Decreased ALFF in the left angular gyrus was also found in the slow-3 band. Only the bilateral PCU/PCC showed a frequency-dependent correlation with the total seizure frequency and full-scale intelligence quotient. Regions having degenerated FC with the bilateral PCU/PCC in BECTS patients were mainly in the left prefrontal cortex and bilateral anterior cingulate cortex for the typical and slow-5 bands, and in the bilateral temporal limbic system and striatum for the slow-4 and slow-3 bands.
CONCLUSION: Alteration of the ALFF and FC differed with distinct frequency bands. Therefore, employing different frequency bands would provide more meaningful findings for BECTS patients.

PMID: 30048931 [PubMed - as supplied by publisher]

Altered resting-state functional connectivity of the putamen and internal globus pallidus is related to speech impairment in Parkinson's disease.

Fri, 07/27/2018 - 12:40
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Altered resting-state functional connectivity of the putamen and internal globus pallidus is related to speech impairment in Parkinson's disease.

Brain Behav. 2018 Jul 25;:e01073

Authors: Manes JL, Tjaden K, Parrish T, Simuni T, Roberts A, Greenlee JD, Corcos DM, Kurani AS

Abstract
INTRODUCTION: Speech impairment in Parkinson's disease (PD) is pervasive, with life-impacting consequences. Yet, little is known about how functional connections between the basal ganglia and cortex relate to PD speech impairment (PDSI). Whole-brain resting-state connectivity analyses of basal ganglia nuclei can expand the understanding of PDSI pathophysiology.
METHODS: Resting-state data from 89 right-handed subjects were downloaded from the Parkinson's Progression Markers Initiative database. Subjects included 12 older healthy controls ("OHC"), 42 PD patients without speech impairment ("PDN"), and 35 PD subjects with speech impairment ("PDSI"). Subjects were assigned to PDN and PDSI groups based on the Movement Disorders Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III speech item scores ("0" vs. "1-4"). Whole-brain functional connectivity was calculated for four basal ganglia seeds in each hemisphere: putamen, caudate, external globus pallidus (GPe), and internal globus pallidus (GPi). For each seed region, group-averaged connectivity maps were compared among OHC, PDN, and PDSI groups using a multivariate ANCOVA controlling for the effects of age and sex. Subsequent planned pairwise t-tests were performed to determine differences between the three groups using a voxel-wise threshold of p < 0.001 and cluster-extent threshold of 272 mm3 (FWE<0.05).
RESULTS: In comparison with OHCs, both PDN and PDSI groups demonstrated significant differences in cortical connectivity with bilateral putamen, bilateral GPe, and right caudate. Compared to the PDN group, the PDSI subjects demonstrated significant differences in cortical connectivity with left putamen and left GPi. PDSI subjects had lower connectivity between the left putamen and left superior temporal gyrus compared to PDN. In addition, PDSI subjects had greater connectivity between left GPi and three cortical regions: left dorsal premotor/laryngeal motor cortex, left angular gyrus, and right angular gyrus.
CONCLUSIONS: The present findings suggest that speech impairment in PD is associated with altered cortical connectivity with left putamen and left GPi.

PMID: 30047249 [PubMed - as supplied by publisher]

Functional Connectivities in the Brain That Mediate the Association Between Depressive Problems and Sleep Quality.

Fri, 07/27/2018 - 12:40
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Functional Connectivities in the Brain That Mediate the Association Between Depressive Problems and Sleep Quality.

JAMA Psychiatry. 2018 Jul 25;:

Authors: Cheng W, Rolls ET, Ruan H, Feng J

Abstract
Importance: Depression is associated with poor sleep quality. Understanding the neural connectivity that underlies both conditions and mediates the association between them is likely to lead to better-directed treatments for depression and associated sleep problems.
Objective: To identify the brain areas that mediate the association of depressive symptoms with poor sleep quality and advance understanding of the differences in brain connectivity in depression.
Design, Setting, and Participants: This study collected data from participants in the Human Connectome Project using the Adult Self-report of Depressive Problems portion of the Achenbach Adult Self-Report for Ages 18-59, a survey of self-reported sleep quality, and resting-state functional magnetic resonance imaging. Cross-validation of the sleep findings was conducted in 8718 participants from the UK Biobank.
Main Outcomes and Measures: Correlations between functional connectivity, scores on the Adult Self-Report of Depressive Problems, and sleep quality.
Results: A total of 1017 participants from the Human Connectome Project (of whom 546 [53.7%] were female; age range, 22 to 35 years) drawn from a general population in the United States were included. The Depressive Problems score was positively correlated with poor sleep quality (r = 0.371; P < .001). A total of 162 functional connectivity links involving areas associated with sleep, such as the precuneus, anterior cingulate cortex, and the lateral orbitofrontal cortex, were identified. Of these links, 39 were also associated with the Depressive Problems scores. The brain areas with increased functional connectivity associated with both sleep and Depressive Problems scores included the lateral orbitofrontal cortex, dorsolateral prefrontal cortex, anterior and posterior cingulate cortices, insula, parahippocampal gyrus, hippocampus, amygdala, temporal cortex, and precuneus. A mediation analysis showed that these functional connectivities underlie the association of the Depressive Problems score with poor sleep quality (β = 0.0139; P < .001).
Conclusions and Relevance: The implication of these findings is that the increased functional connectivity between these brain regions provides a neural basis for the association between depression and poor sleep quality. An important finding was that the Depressive Problems scores in this general population were correlated with functional connectivities between areas, including the lateral orbitofrontal cortex, cingulate cortex, precuneus, angular gyrus, and temporal cortex. The findings have implications for the treatment of depression and poor sleep quality.

PMID: 30046833 [PubMed - as supplied by publisher]

Weighted Symbolic Dependence Metric (wSDM) for fMRI resting-state connectivity: A multicentric validation for frontotemporal dementia.

Fri, 07/27/2018 - 12:40
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Weighted Symbolic Dependence Metric (wSDM) for fMRI resting-state connectivity: A multicentric validation for frontotemporal dementia.

Sci Rep. 2018 Jul 25;8(1):11181

Authors: Moguilner S, García AM, Mikulan E, Hesse E, García-Cordero I, Melloni M, Cervetto S, Serrano C, Herrera E, Reyes P, Matallana D, Manes F, Ibáñez A, Sedeño L

Abstract
The search for biomarkers of neurodegenerative diseases via fMRI functional connectivity (FC) research has yielded inconsistent results. Yet, most FC studies are blind to non-linear brain dynamics. To circumvent this limitation, we developed a "weighted Symbolic Dependence Metric" (wSDM) measure. Using symbolic transforms, we factor in local and global temporal features of the BOLD signal to weigh a robust copula-based dependence measure by symbolic similarity, capturing both linear and non-linear associations. We compared this measure with a linear connectivity metric (Pearson's R) in its capacity to identify patients with behavioral variant frontotemporal dementia (bvFTD) and controls based on resting-state data. We recruited participants from two international centers with different MRI recordings to assess the consistency of our measure across heterogeneous conditions. First, a seed-analysis comparison of the salience network (a specific target of bvFTD) and the default-mode network (as a complementary control) between patients and controls showed that wSDM yields better identification of resting-state networks. Moreover, machine learning analysis revealed that wSDM yielded higher classification accuracy. These results were consistent across centers, highlighting their robustness despite heterogeneous conditions. Our findings underscore the potential of wSDM to assess fMRI-derived FC data, and to identify sensitive biomarkers in bvFTD.

PMID: 30046142 [PubMed - in process]

Functional subdivisions of the hypothalamus using areal parcellation and their signal changes related to glucose metabolism.

Thu, 07/26/2018 - 18:00
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Functional subdivisions of the hypothalamus using areal parcellation and their signal changes related to glucose metabolism.

Neuroimage. 2017 Nov 15;162:1-12

Authors: Osada T, Suzuki R, Ogawa A, Tanaka M, Hori M, Aoki S, Tamura Y, Watada H, Kawamori R, Konishi S

Abstract
The hypothalamus consists of numerous nuclei, and is regarded as the highest center for various autonomic functions. Although each hypothalamic nucleus implements a distinct function, it remains difficult to investigate the human hypothalamus at the nucleus level. In the present high-resolution functional MRI study, we utilized areal parcellation to discriminate individual nuclei in the human hypothalamus based on areal profiles of resting-state functional connectivity. The areal parcellation detected ten foci that were expected to represent hypothalamic nuclei, and the locations of the foci were consistent with those of the hypothalamic nuclei identified in previous histological studies. Regions of interest (ROI) analyses revealed contrasting brain activity changes following glucose ingestion: decrease in the ventromedial hypothalamic nucleus and increase in the lateral hypothalamic area in parallel with blood glucose increase. Moreover, decreased brain activity in the arcuate nucleus predicted future elevation of blood insulin during the first 10 min after glucose ingestion. These results suggest that the hypothalamic nuclei can putatively be determined using areal parcellation, and that the ROI analysis of the human hypothalamic nuclei is useful for future scientific and clinical investigations into the autonomic functions.

PMID: 28844890 [PubMed - indexed for MEDLINE]

Sensory-biased attention networks in human lateral frontal cortex revealed by intrinsic functional connectivity.

Thu, 07/26/2018 - 18:00
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Sensory-biased attention networks in human lateral frontal cortex revealed by intrinsic functional connectivity.

Neuroimage. 2017 Nov 15;162:362-372

Authors: Tobyne SM, Osher DE, Michalka SW, Somers DC

Abstract
Human frontal cortex is commonly described as being insensitive to sensory modality, however several recent studies cast doubt on this view. Our laboratory previously reported two visual-biased attention regions interleaved with two auditory-biased attention regions, bilaterally, within lateral frontal cortex. These regions selectively formed functional networks with posterior visual-biased and auditory-biased attention regions. Here, we conducted a series of functional connectivity analyses to validate and expand this analysis to 469 subjects from the Human Connectome Project (HCP). Functional connectivity analyses replicated the original findings and revealed a novel hemispheric connectivity bias. We also subdivided lateral frontal cortex into 21 thin-slice ROIs and observed bilateral patterns of spatially alternating visual-biased and auditory-biased attention network connectivity. Finally, we performed a correlation difference analysis that revealed five additional bilateral lateral frontal regions differentially connected to either the visual-biased or auditory-biased attention networks. These findings leverage the HCP dataset to demonstrate that sensory-biased attention networks may have widespread influence in lateral frontal cortical organization.

PMID: 28830764 [PubMed - indexed for MEDLINE]

Understanding Neurogastroenterology From Neuroimaging Perspective: A Comprehensive Review of Functional and Structural Brain Imaging in Functional Gastrointestinal Disorders.

Wed, 07/25/2018 - 16:40

Understanding Neurogastroenterology From Neuroimaging Perspective: A Comprehensive Review of Functional and Structural Brain Imaging in Functional Gastrointestinal Disorders.

J Neurogastroenterol Motil. 2018 Jul 24;:

Authors: Kano M, Dupont P, Aziz Q, Fukudo S

Abstract
This review provides a comprehensive overview of brain imaging studies of the brain-gut interaction in functional gastrointestinal disorders (FGIDs). Functional neuroimaging studies during gut stimulation have shown enhanced brain responses in regions related to sensory processing of the homeostatic condition of the gut (homeostatic afferent) and responses to salience stimuli (salience network), as well as increased and decreased brain activity in the emotional response areas and reduced activation in areas associated with the top-down modulation of visceral afferent signals. Altered central regulation of the endocrine and autonomic nervous responses, the key mediators of the brain-gut axis, has been demonstrated. Studies using resting-state functional magnetic resonance imaging reported abnormal local and global connectivity in the areas related to pain processing and the default mode network (a physiological baseline of brain activity at rest associated with self-awareness and memory) in FGIDs. Structural imaging with brain morphometry and diffusion imaging demonstrated altered gray- and white-matter structures in areas that also showed changes in functional imaging studies, although this requires replication. Molecular imaging by magnetic resonance spectroscopy and positron emission tomography in FGIDs remains relatively sparse. Progress using analytical methods such as machine learning algorithms may shift neuroimaging studies from brain mapping to predicting clinical outcomes. Because several factors contribute to the pathophysiology of FGIDs and because its population is quite heterogeneous, a new model is needed in future studies to assess the importance of the factors and brain functions that are responsible for an optimal homeostatic state.

PMID: 30041284 [PubMed - as supplied by publisher]

Resting State fMRI in Rodents.

Wed, 07/25/2018 - 16:40

Resting State fMRI in Rodents.

Curr Protoc Neurosci. 2018 Apr;83(1):e45

Authors: Pan WJ, Billings J, Nezafati M, Abbas A, Keilholz S

Abstract
Resting state functional MRI (fMRI) and functional connectivity are widely applied in humans to examine the role of brain networks in normal function and dysfunction. A similar approach can be taken in rodents, either to obtain translational measures in models of brain disorders or to more carefully examine the neurophysiological underpinnings of the networks. A protocol for resting state functional connectivity in the anesthetized rat, from animal setup to data acquisition to possible pipelines for data analysis, is described. © 2018 by John Wiley & Sons, Inc.

PMID: 30040200 [PubMed - in process]

Functional and anatomical connectivity-based parcellation of human cingulate cortex.

Wed, 07/25/2018 - 16:40
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Functional and anatomical connectivity-based parcellation of human cingulate cortex.

Brain Behav. 2018 Jul 24;:e01070

Authors: Jin F, Zheng P, Liu H, Guo H, Sun Z

Abstract
INTRODUCTION: Human cingulate cortex (CC) has been implicated in many functions, which is highly suggestive of the existence of functional subregions.
METHODS: In this study, we used resting-state functional magnetic resonance imaging (rs-fMRI) and diffusion tensor imaging (DTI) to parcellate the human cingulate cortex (CC) based on resting-state functional connectivity (rsFC) patterns and anatomical connectivity (AC) patterns, to analyze the rsFC patterns and the AC patterns of different subregions, and to recognize whether the parcellation results obtained by the two different methods were consistent.
RESULTS: The CC was divided into six functional subregions, including the anterior cingulate cortex, dorsal anterior midcingulate cortex, ventral anterior midcingulate cortex, posterior midcingulate cortex, dorsal posterior cingulate cortex, and ventral posterior cingulate cortex. The CC was also divided into ten anatomical subregions, termed Subregion 1 (S1) to Subregion 10 (S10). Each subregion showed specific connectivity patterns, although the functional subregions and the anatomical subregions were internally consistent.
CONCLUSIONS: Using different model MRI images, we established a parcellation scheme, which is internally consistent for the human CC, which may provide an in vivo guide for subregion-level studies and improve our understanding of this brain area at subregional levels.

PMID: 30039643 [PubMed - as supplied by publisher]

Amplification and Suppression of Distinct Brain-wide Activity Patterns by Catecholamines.

Wed, 07/25/2018 - 16:40
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Amplification and Suppression of Distinct Brain-wide Activity Patterns by Catecholamines.

J Neurosci. 2018 Jul 23;:

Authors: van den Brink RL, Nieuwenhuis S, Donner TH

Abstract
The widely projecting catecholaminergic (norepinephrine and dopamine) neurotransmitter systems profoundly shape the state of neuronal networks in the forebrain. Current models posit that the effects of catecholaminergic modulation on network dynamics are homogenous across the brain. However, the brain is equipped with a variety of catecholamine receptors with distinct functional effects and heterogeneous density across brain regions. Consequently, catecholaminergic effects on brain-wide network dynamics might be more spatially specific than assumed. We tested this idea through the analysis of functional magnetic resonance imaging (fMRI) measurements performed in humans (19 females, 5 males) at 'rest' under pharmacological (atomoxetine-induced) elevation of catecholamine levels. We used a linear decomposition technique to identify spatial patterns of correlated fMRI signal fluctuations that were either increased or decreased by atomoxetine. This yielded two distinct spatial patterns, each expressing reliable and specific drug effects. The spatial structure of both fluctuation patterns resembled the spatial distribution of the expression of catecholamine receptor genes: α1 norepinephrine receptors (for the fluctuation pattern: placebo > atomoxetine), 'D2-like' dopamine receptors (pattern: atomoxetine > placebo), and β norepinephrine receptors (for both patterns, with correlations of opposite sign). We conclude that catecholaminergic effects on the forebrain are spatially more structured than traditionally assumed and at least in part explained by the heterogeneous distribution of various catecholamine receptors. Our findings link catecholaminergic effects on large-scale brain networks to low-level characteristics of the underlying neurotransmitter systems. They also provide key constraints for the development of realistic models of neuromodulatory effects on large-scale brain network dynamics.SIGNIFICANCE STATEMENTThe catecholamines norepinephrine and dopamine are an important class of modulatory neurotransmitters. Because of the widespread and diffuse release of these neuromodulators, it has commonly been assumed that their effects on neural interactions are homogenous across the brain. Here, we present results from the human brain that challenge this view. We pharmacologically increased catecholamine levels and imaged the effects on the spontaneous covariations between brain-wide fMRI signals at 'rest'. We identified two distinct spatial patterns of covariations: one that was amplified and another that was suppressed by catecholamines. Each pattern was associated with the heterogeneous spatial distribution of the expression of distinct catecholamine receptor genes. Our results provide novel insights into the catecholaminergic modulation of large-scale human brain dynamics.

PMID: 30037827 [PubMed - as supplied by publisher]

Near-infrared spectroscopy patterns of cortical activity during gait in Parkinson's disease patients treated with DBS STN.

Wed, 07/25/2018 - 16:40
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Near-infrared spectroscopy patterns of cortical activity during gait in Parkinson's disease patients treated with DBS STN.

Gait Posture. 2018 Jul 17;:

Authors: Klempíř O, Krupička R, Mehnert J, Čejka V, Peterová K, Plaňanská E, Brožová H, Růžička E, Szabó Z, Jech R

Abstract
Disorders of gait seriously affect the functional state and quality of life of patients with Parkinson's disease (PD). Impaired brain function underlies disorders of movement control in PD, however functional brain imaging with magnetic resonance (fMRI) is not feasible during gait. Near-Infrared Spectroscopy (NIRS) is a portable imaging method for measuring brain activity. It uses low-energy optical radiation to detect local changes of (de)oxyhemoglobin concentration in the cerebral cortex, like a fMRI. We included 8 patients with advanced PD chronically treated with DBS STN. Brain activity was recorded with the NIRSport. Gait was examined in 10 cycles, during which the active and resting phases alternated. Changes in oxyhemoglobin concentration were calculated from the native NIRS signal using a modified transformation of the Lambert-Beer Law. The signals were filtered in the 0.015-0.3 Hz band and the least-squares algorithm was fitted with the HRF function for each cycle separately, from which the median was finally calculated. The activity of the motor cortex was significantly higher during gait in the OFF compared to ON state (p = 0.02). In contrast, in other regions no differences were found. A higher motor cortex activity shown in the DBS OFF compared to ON state may reflect the impairment of gait control in PD. In general terms, the present study demonstrates the potential utility of the NIRS method in detecting functional changes of the brain during gait in patients with PD.

PMID: 30037751 [PubMed - as supplied by publisher]

Frequency-selective alteration in the resting-state corticostriatal-thalamo-cortical circuit correlates with symptoms severity in first-episode drug-naive patients with schizophrenia.

Wed, 07/25/2018 - 16:40
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Frequency-selective alteration in the resting-state corticostriatal-thalamo-cortical circuit correlates with symptoms severity in first-episode drug-naive patients with schizophrenia.

Schizophr Res. 2017 Nov;189:175-180

Authors: Han S, Zong X, Hu M, Yu Y, Wang X, Long Z, Wang Y, Chen X, Chen H

Abstract
Schizophrenia is a prototypical disorder of brain connectivity with altered neural activity in regions extending throughout the brain. Regions, including the subcortex and cortex, present activity mainly within a specific frequency band in resting-state. Whether these altered resting-state functional connections also present frequency specificity is unknown. In the present study, empirical mode decomposition, which is a pure data-driven method suitable for nonlinear and nonstationary signals, was used to decompose blood-oxygen-level-dependent (BOLD) signals into different intrinsic frequency bands. Our study included 42 first-episode drug-naive patients with schizophrenia and 38 controls. Significant aberration in functional connectivity was observed only at a higher frequency range (the peak spectral density power was 0.06Hz). In this frequency band, patients with schizophrenia showed significantly increased functional connections between the bilateral cuneus and right supplementary motor area, reduced connections within the basal ganglia, and reduced connections between the dorsal striatum and left supplementary motor area. The dysfunction of the frontal gyrus significantly correlated with the dysfunction of the basal ganglia. Notably, these altered connections were significantly correlated with symptom severity. Our results demonstrate that frequency-selective altered corticostriatal-thalamo-cortical circuits in patients with schizophrenia are associated with symptoms severity.

PMID: 28236519 [PubMed - indexed for MEDLINE]

Brain connectivity changes when comparing effects of subthalamic deep brain stimulation with levodopa treatment in Parkinson's disease.

Tue, 07/24/2018 - 15:40

Brain connectivity changes when comparing effects of subthalamic deep brain stimulation with levodopa treatment in Parkinson's disease.

Neuroimage Clin. 2018;19:1025-1035

Authors: Mueller K, Jech R, Růžička F, Holiga Š, Ballarini T, Bezdicek O, Möller HE, Vymazal J, Růžička E, Schroeter ML, Urgošík D

Abstract
Levodopa and, later, deep brain stimulation (DBS) have become the mainstays of therapy for motor symptoms associated with Parkinson's disease (PD). Although these therapeutic options lead to similar clinical outcomes, the neural mechanisms underlying their efficacy are different. Therefore, investigating the differential effects of DBS and levodopa on functional brain architecture and associated motor improvement is of paramount interest. Namely, we expected changes in functional brain connectivity patterns when comparing levodopa treatment with DBS. Clinical assessment and functional magnetic resonance imaging (fMRI) was performed before and after implanting electrodes for DBS in the subthalamic nucleus (STN) in 13 PD patients suffering from severe levodopa-induced motor fluctuations and peak-of-dose dyskinesia. All measurements were acquired in a within subject-design with and without levodopa treatment, and with and without DBS. Brain connectivity changes were computed using eigenvector centrality (EC) that offers a data-driven and parameter-free approach-similarly to Google's PageRank algorithm-revealing brain regions that have an increased connectivity to other regions that are highly connected, too. Both levodopa and DBS led to comparable improvement of motor symptoms as measured with the Unified Parkinson's Disease Rating Scale motor score (UPDRS-III). However, this similar therapeutic effect was underpinned by different connectivity modulations within the motor system. In particular, EC revealed a major increase of interconnectedness in the left and right motor cortex when comparing DBS to levodopa. This was accompanied by an increase of connectivity of these motor hubs with the thalamus and cerebellum. We observed, for the first time, significant functional connectivity changes when comparing the effects of STN DBS and oral levodopa administration, revealing different treatment-specific mechanisms linked to clinical benefit in PD. Specifically, in contrast to levodopa treatment, STN DBS was associated with increased connectivity within the cortico-thalamo-cerebellar network. Moreover, given the favorable effects of STN DBS on motor complications, the changes in the patients' clinical profile might also contribute to connectivity changes associated with STN-DBS. Understanding the observed connectivity changes may be essential for enhancing the effectiveness of DBS treatment, and for better defining the pathophysiology of the disrupted motor network in PD.

PMID: 30035027 [PubMed - in process]

Stratification of MDD and GAD patients by resting state brain connectivity predicts cognitive bias.

Tue, 07/24/2018 - 15:40

Stratification of MDD and GAD patients by resting state brain connectivity predicts cognitive bias.

Neuroimage Clin. 2018;19:425-433

Authors: Bijsterbosch JD, Ansari TL, Smith S, Gauld O, Zika O, Boessenkool S, Browning M, Reinecke A, Bishop SJ

Abstract
Patients with Generalized Anxiety Disorder (GAD) and Major Depressive Disorder (MDD) show between-group comorbidity and symptom overlap, and within-group heterogeneity. Resting state functional connectivity might provide an alternate, biologically informed means by which to stratify patients with GAD or MDD. Resting state functional magnetic resonance imaging data were acquired from 23 adults with GAD, 21 adults with MDD, and 27 healthy adult control participants. We investigated whether within- or between-network connectivity indices from five resting state networks predicted scores on continuous measures of depression and anxiety. Successful predictors were used to stratify participants into two new groups. We examined whether this stratification predicted attentional bias towards threat and whether this varied between patients and controls. Depression scores were linked to elevated connectivity within a limbic network including the amygdala, hippocampus, VMPFC and subgenual ACC. Patients with GAD or MDD with high limbic connectivity showed poorer performance on an attention-to-threat task than patients with low limbic connectivity. No parallel effect was observed for control participants, resulting in an interaction of clinical status by resting state group. Our findings provide initial evidence for the external validity of stratification of MDD and GAD patients by functional connectivity markers. This stratification cuts across diagnostic boundaries and might valuably inform future intervention studies. Our findings also highlight that biomarkers of interest can have different cognitive correlates in individuals with versus without clinically significant symptomatology. This might reflect protective influences leading to resilience in some individuals but not others.

PMID: 30035026 [PubMed - in process]

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