New resting-state fMRI related studies at PubMed

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Twitches, Blinks, and Fidgets: Important Generators of Ongoing Neural Activity.

Sat, 10/13/2018 - 11:40

Twitches, Blinks, and Fidgets: Important Generators of Ongoing Neural Activity.

Neuroscientist. 2018 Oct 12;:1073858418805427

Authors: Drew PJ, Winder AT, Zhang Q

Abstract
Animals and humans continuously engage in small, spontaneous motor actions, such as blinking, whisking, and postural adjustments ("fidgeting"). These movements are accompanied by changes in neural activity in sensory and motor regions of the brain. The frequency of these motions varies in time, is affected by sensory stimuli, arousal levels, and pathology. These fidgeting behaviors can be entrained by sensory stimuli. Fidgeting behaviors will cause distributed, bilateral functional activation in the 0.01 to 0.1 Hz frequency range that will show up in functional magnetic resonance imaging and wide-field calcium neuroimaging studies, and will contribute to the observed functional connectivity among brain regions. However, despite the large potential of these behaviors to drive brain-wide activity, these fidget-like behaviors are rarely monitored. We argue that studies of spontaneous and evoked brain dynamics in awake animals and humans should closely monitor these fidgeting behaviors. Differences in these fidgeting behaviors due to arousal or pathology will "contaminate" ongoing neural activity, and lead to apparent differences in functional connectivity. Monitoring and accounting for the brain-wide activations by these behaviors is essential during experiments to differentiate fidget-driven activity from internally driven neural dynamics.

PMID: 30311838 [PubMed - as supplied by publisher]

Extreme male developmental trajectories of homotopic brain connectivity in autism.

Sat, 10/13/2018 - 11:40
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Extreme male developmental trajectories of homotopic brain connectivity in autism.

Hum Brain Mapp. 2018 Oct 11;:

Authors: Kozhemiako N, Vakorin V, Nunes AS, Iarocci G, Ribary U, Doesburg SM

Abstract
It has been proposed that autism spectrum disorder (ASD) may be characterized by an extreme male brain (EMB) pattern of brain development. Here, we performed the first investigation of how age-related changes in functional brain connectivity may be expressed differently in females and males with ASD. We analyzed resting-state functional magnetic resonance imaging data of 107 typically developing (TD) females, 114 TD males, 104 females, and 115 males with ASD (6-26 years) from the autism brain imaging data exchange repository. We explored how interhemispheric homotopic connectivity and its maturational curvatures change across groups. Differences between ASD and TD and between females and males with ASD were observed for the rate of changes in connectivity in the absence of overall differences in connectivity. The largest portion of variance in age-related changes in connectivity was described through similarities between TD males, ASD males, and ASD females, in contrast to TD females. We found that shape of developmental curvature is associated with symptomatology in both males and females with ASD. We demonstrated that females and males with ASD tended to follow the male pattern of developmental changes in interhemispheric connectivity, supporting the EMB theory of ASD.

PMID: 30311349 [PubMed - as supplied by publisher]

The corticotopic organization of the human basal forebrain as revealed by regionally selective functional connectivity profiles.

Sat, 10/13/2018 - 11:40
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The corticotopic organization of the human basal forebrain as revealed by regionally selective functional connectivity profiles.

Hum Brain Mapp. 2018 Oct 11;:

Authors: Fritz HJ, Ray N, Dyrba M, Sorg C, Teipel S, Grothe MJ

Abstract
The cholinergic basal forebrain (CBF), comprising different groups of cortically projecting cholinergic neurons, plays a crucial role in higher cognitive processes and has been implicated in diverse neuropsychiatric disorders. A distinct corticotopic organization of CBF projections has been revealed in animal studies, but little is known about their organization in the human brain. We explored regional differences in functional connectivity (FC) profiles within the human CBF by applying a clustering approach to resting-state functional magnetic resonance imaging (rs-fMRI) data of healthy adult individuals (N = 85; 19-85 years). We further examined effects of age on FC of the identified CBF clusters and assessed the reproducibility of cluster-specific FC profiles in independent data from healthy older individuals (N = 25; 65-89 years). Results showed that the human CBF is functionally organized into distinct anterior-medial and posterior-lateral subdivisions that largely follow anatomically defined boundaries of the medial septum/diagonal band and nucleus basalis Meynert. The anterior-medial CBF subdivision was characterized by connectivity with the hippocampus and interconnected nodes of an extended medial cortical memory network, whereas the posterior-lateral subdivision was specifically connected to anterior insula and dorsal anterior cingulate components of a salience/attention network. FC of both CBF subdivisions declined with increasing age, but the overall topography of subregion-specific FC profiles was reproduced in independent rs-fMRI data of healthy older individuals acquired in a typical clinical setting. Rs-fMRI-based assessments of subregion-specific CBF function may complement established volumetric approaches for the in vivo study of CBF involvement in neuropsychiatric disorders.

PMID: 30311315 [PubMed - as supplied by publisher]

Long-chain polyunsaturated fatty acid supplementation in the first year of life affects brain function, structure, and metabolism at age nine years.

Sat, 10/13/2018 - 11:40
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Long-chain polyunsaturated fatty acid supplementation in the first year of life affects brain function, structure, and metabolism at age nine years.

Dev Psychobiol. 2018 Oct 11;:

Authors: Lepping RJ, Honea RA, Martin LE, Liao K, Choi IY, Lee P, Papa VB, Brooks WM, Shaddy DJ, Carlson SE, Colombo J, Gustafson KM

Abstract
The present study sought to determine whether supplementation of long-chain polyunsaturated fatty acids (LCPUFA) during the first year of life influenced brain function, structure, and metabolism at 9 years of age. Newborns were randomly assigned to consume formula containing either no LCPUFA (control) or formula with 0.64% of total fatty acids as arachidonic acid (ARA; 20:4n6) and variable amounts of docosahexaenoic acid (DHA; 22:6n3) (0.32%, 0.64%, or 0.96% of total fatty acids) from birth to 12 months. At age 9 years (±0.6), 42 children enrolled in a follow-up multimodal magnetic resonance imaging (MRI) study including functional (fMRI, Flanker task), resting state (rsMRI), anatomic, and proton magnetic resonance spectroscopy (1 H MRS). fMRI analysis using the Flanker task found that trials requiring greater inhibition elicited greater brain activation in LCPUFA-supplemented children in anterior cingulate cortex (ACC) and parietal regions. rsMRI analysis showed that children in the 0.64% group exhibited greater connectivity between prefrontal and parietal regions compared to all other groups. In addition, voxel-based analysis (VBM) revealed that the 0.32% and 0.64% groups had greater white matter volume in ACC and parietal regions compared to controls and the 0.96% group. Finally, 1 H MRS data analysis identified that N-acetylaspartate (NAA) and myo-inositol (mI) were higher in LCPUFA groups compared to the control group. LCPUFA supplementation during infancy has lasting effects on brain structure, function, and neurochemical concentrations in regions associated with attention (parietal) and inhibition (ACC), as well as neurochemicals associated with neuronal integrity (NAA) and brain cell signaling (mI).

PMID: 30311214 [PubMed - as supplied by publisher]

The relationship between amplitude of low frequency fluctuations and gray matter volume of the mirror neuron system: Differences between low disability multiple sclerosis patients and healthy controls.

Sat, 10/13/2018 - 11:40
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The relationship between amplitude of low frequency fluctuations and gray matter volume of the mirror neuron system: Differences between low disability multiple sclerosis patients and healthy controls.

IBRO Rep. 2018 Dec;5:60-66

Authors: Plata-Bello J, Pérez-Martín Y, Castañón-Pérez A, Modroño C, Hernández-Martín E, González-Platas M, Marcano F, González-Mora JL

Abstract
The study of the relationship between function and structure of the brain could be particularly interesting in neurodegenerative diseases like multiple sclerosis (MS). The aim of the present work is to identify differences of the amplitude of low frequency fluctuations (ALFF) in the mirror neuron system (MNS) between MS patients and healthy controls and to study the relationship between ALFF and the gray matter volume (GMV) of the regions that belong to the MNS. Relapsing-remitting MS patients with minor disability were compared to healthy controls (HC) using resting-state functional magnetic resonance imaging (fMRI), anatomic T1 weighted images and diffusion tensor imaging (DTI). Region of interest (ROI) analyses was performed in the MNS regions. A decrease of ALFF in MS patients was observed in the left inferior frontal gyrus (IFG). Furthermore, a correlation between ALFF in the IFG and the GMV of the left inferior parietal lobule (IPL) was identified. This relationship was different for MS patients than for HC, which may be associated with changes in diffusivity measures which were impaired in MS patients. MS patients with low disability may show ALFF differences in the MNS without clinical correspondence. This functional difference may be associated with cortical and subcortical changes related to the disease.

PMID: 30310873 [PubMed]

Dynamic Graph Theoretical Analysis of Functional Connectivity in Parkinson's Disease: The Importance of Fiedler Value.

Fri, 10/12/2018 - 10:40

Dynamic Graph Theoretical Analysis of Functional Connectivity in Parkinson's Disease: The Importance of Fiedler Value.

IEEE J Biomed Health Inform. 2018 Oct 11;:

Authors: Cai J, Liu A, Mi T, Garg S, Trappe W, McKeown MJ, Wang ZJ

Abstract
Graph theoretical analysis is a powerful tool for quantitatively understanding the topological properties of complex networks, such as system-level descriptions of brain connectivity. In conventional functional connectivity analysis, brain connectivity is assumed to be temporally stationary, while increasing evidence suggests that functional connectivity exhibits temporal variations during dynamic brain activity. Although a number of methods have been developed to estimate time-dependent brain connectivity, there is a paucity of studies examining the utility of brain dynamics for assessing brain disease states. Therefore, this paper aims to assess brain connectivity dynamics in Parkinson's disease (PD) and determine the utility of such dynamic graph measures as potential components to an imaging biomarker. Resting-state fMRI data were collected from 29 healthy controls (HCs) and 69 PD subjects. Time-varying functional connectivity was first estimated using a sliding windowed sparse inverse covariance matrix. Then, a collection of graph measures, including the Fiedler value - an indicator of how well connected a network is - were computed and the dynamics of the graph measures were investigated. The results demonstrated that PD subjects had a lower variability in the Fiedler value, modularity, and global efficiency, suggesting both abnormal dynamic global integration and local segregation of brain networks in PD. Autoregressive models fitted to the dynamic graph measures suggested that Fiedler value, characteristic path length, global efficiency and modularity were all less deterministic in PD. With canonical correlation analysis (CCA), the altered dynamics of functional connectivity networks, and particularly dynamic Fiedler value, were shown to be related with disease severity and other clinical variables including age. Similarly, Fiedler value was the most important feature for classification. Collectively, our findings demonstrate altered dynamic graph properties, and in particular the Fiedler value, provide an additional dimension upon which to non-invasively and quantitatively assess PD.

PMID: 30307882 [PubMed - as supplied by publisher]

Neural basis of smoking-induced relief of craving and negative affect: Contribution of nicotine.

Fri, 10/12/2018 - 10:40

Neural basis of smoking-induced relief of craving and negative affect: Contribution of nicotine.

Addict Biol. 2018 Oct 11;:

Authors: Faulkner P, Ghahremani DG, Tyndale RF, Paterson NE, Cox C, Ginder N, Hellemann G, London ED

Abstract
Smoking-induced relief of craving and withdrawal promotes continued cigarette use. Understanding how relief is produced and the role of nicotine in this process may facilitate development of new smoking-cessation therapies. As the US Food and Drug Administration considers setting a standard for reduced nicotine content in cigarettes to improve public health, knowledge of how nicotine contributes to relief also can inform policy. We assessed effects of nicotine using resting state functional magnetic resonance imaging (MRI) and behavioral assessments of craving and negative affect. Twenty-one young (18-25 years old) daily smokers underwent overnight abstinence on 4 days. On each of the following mornings, they self-rated their cigarette craving and negative affect and underwent resting-state functional MRI (fMRI) before and after smoking a cigarette that delivered 0.027, 0.110, 0.231, or 0.763 mg of nicotine. Functional connectivity between the anterior insula and anterior cingulate cortex (ACC) and between the nucleus accumbens and orbitofrontal cortex (OFC) was assessed. Smoking reduced craving, negative affect, and nucleus accumbens-OFC connectivity irrespective of nicotine dose, with positive correlations of the effects on behavioral and connectivity measures. Only the highest nicotine dose (0.763 mg) reduced right anterior insula-ACC connectivity; this reduction was positively correlated with the behavioral effects of the 0.763-mg dose only. While nicotine-based therapies may act on right anterior insula-ACC functional circuits to facilitate smoking cessation, non-nicotine (eg, the conditioned and sensorimotor) aspects of smoking may promote cessation by reducing OFC-accumbens connectivity to alleviate withdrawal.

PMID: 30307083 [PubMed - as supplied by publisher]

Machine learning multivariate pattern analysis predicts classification of posttraumatic stress disorder and its dissociative subtype: a multimodal neuroimaging approach.

Fri, 10/12/2018 - 10:40

Machine learning multivariate pattern analysis predicts classification of posttraumatic stress disorder and its dissociative subtype: a multimodal neuroimaging approach.

Psychol Med. 2018 Oct 11;:1-11

Authors: Nicholson AA, Densmore M, McKinnon MC, Neufeld RWJ, Frewen PA, Théberge J, Jetly R, Richardson JD, Lanius RA

Abstract
BACKGROUND: The field of psychiatry would benefit significantly from developing objective biomarkers that could facilitate the early identification of heterogeneous subtypes of illness. Critically, although machine learning pattern recognition methods have been applied recently to predict many psychiatric disorders, these techniques have not been utilized to predict subtypes of posttraumatic stress disorder (PTSD), including the dissociative subtype of PTSD (PTSD + DS).
METHODS: Using Multiclass Gaussian Process Classification within PRoNTo, we examined the classification accuracy of: (i) the mean amplitude of low-frequency fluctuations (mALFF; reflecting spontaneous neural activity during rest); and (ii) seed-based amygdala complex functional connectivity within 181 participants [PTSD (n = 81); PTSD + DS (n = 49); and age-matched healthy trauma-unexposed controls (n = 51)]. We also computed mass-univariate analyses in order to observe regional group differences [false-discovery-rate (FDR)-cluster corrected p < 0.05, k = 20].
RESULTS: We found that extracted features could predict accurately the classification of PTSD, PTSD + DS, and healthy controls, using both resting-state mALFF (91.63% balanced accuracy, p < 0.001) and amygdala complex connectivity maps (85.00% balanced accuracy, p < 0.001). These results were replicated using independent machine learning algorithms/cross-validation procedures. Moreover, areas weighted as being most important for group classification also displayed significant group differences at the univariate level. Here, whereas the PTSD + DS group displayed increased activation within emotion regulation regions, the PTSD group showed increased activation within the amygdala, globus pallidus, and motor/somatosensory regions.
CONCLUSION: The current study has significant implications for advancing machine learning applications within the field of psychiatry, as well as for developing objective biomarkers indicative of diagnostic heterogeneity.

PMID: 30306886 [PubMed - as supplied by publisher]

Functional Brain Network Changes Following Use of an Allostatic, Closed-Loop, Acoustic Stimulation Neurotechnology for Military-Related Traumatic Stress.

Fri, 10/12/2018 - 10:40
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Functional Brain Network Changes Following Use of an Allostatic, Closed-Loop, Acoustic Stimulation Neurotechnology for Military-Related Traumatic Stress.

J Neuroimaging. 2018 Oct 10;:

Authors: Lee SW, Laurienti PJ, Burdette JH, Tegeler CL, Morgan AR, Simpson SL, Gerdes L, Tegeler CH

Abstract
BACKGROUND AND PURPOSE: Post-traumatic stress disorder is associated with connectivity changes in the default mode, central executive, and salience networks, and other brain regions. This study evaluated changes in network connectivity associated with usage of High-resolution, relational, resonance-based electroencephalic mirroring (HIRREM® ; Brain State Technologies, Scottsdale, AZ), a closed-loop, allostatic, acoustic stimulation neurotechnology, for military-related traumatic stress.
METHODS: Eighteen participants (17 males, mean age 41 years [SD = 7], 15 active duty) enrolled in an IRB approved pilot trial for symptoms of military-related traumatic stress. Participants received 19.5 (1.1) HIRREM sessions over 12 days. Symptoms, physiological and functional measures, and whole brain resting MRI were collected before and after HIRREM. Six whole brain functional networks were evaluated using summary variables and community structure of predefined networks. Pre to postintervention change was analyzed using paired-sample statistical tests.
RESULTS: Postintervention, there was an overall increase in connectivity of the default mode network (P = .0094). There were decreases of community structure in both the anterior portion of the default mode (medial prefrontal cortex, P = .0097) and in the sensorimotor (P = .005) network. There were no statistically significant changes at the whole brain level, or in the central executive, salience, or other networks analyzed. Participants demonstrated significant improvements in clinical symptoms, as well as autonomic cardiovascular regulation, which have been reported previously.
CONCLUSIONS: Use of closed-loop, allostatic, acoustic stimulation neurotechnology (HIRREM) was associated with connectivity changes in the default mode and sensorimotor networks, in directions that may have explained the subjects' clinical improvements.

PMID: 30302866 [PubMed - as supplied by publisher]

Increased posterior cingulate cortex efficiency may predict cognitive impairment in asymptomatic HIV patients.

Fri, 10/12/2018 - 10:40
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Increased posterior cingulate cortex efficiency may predict cognitive impairment in asymptomatic HIV patients.

Neuroradiol J. 2018 Aug;31(4):372-378

Authors: Ventura N, Douw L, Correa DG, Netto TM, Cabral RF, Lopes FCR, Gasparetto EL

Abstract
Purpose Despite antiretroviral therapy, approximately half of individuals with human immunodeficiency virus (HIV) will develop HIV-associated neurocognitive disorder (HAND). Efficiency of brain networks is of great importance for cognitive functioning, since functional networks may reorganize or compensate to preserve normal cognition. This study aims to compare efficiency of the posterior cingulate cortex (PCC) between patients with and without HAND and controls. We hypothesize HAND negative (HAND-) patients will show higher PCC efficiency than HAND positive (HAND+) patients. Methods A total of 10 HAND + patients were compared with 9 HAND- patients and 17 gender-, age-, and education-matched controls. Resting-state functional MRI was acquired with a 3 Tesla scanner. Local efficiency, a measure of network functioning, was investigated for PCC. Network differences among HAND + , HAND- patients and controls were tested as well as correlations between network parameters and cognitive test performance in different domains. Results HAND- patients showed significantly increased PCC efficiency compared with healthy controls ( p = 0.015). No differences were observed between HAND + patients and either controls ( p = 0.327) or HAND- patients ( p = 0.152). In HAND- patients, PCC efficiency was positively related with cognitive performance in the attention/working memory domain ( p = 0.003). Conversely, in HAND + patients, PCC efficiency was negatively correlated with performance in the abstraction/executive domain ( p = 0.002). Conclusion HAND- patients showed a higher level of PCC efficiency compared with healthy subjects, and PCC efficiency was positively related to cognitive performance. These results support the functional reorganization hypothesis, that increased PCC efficiency is a compensation technique to maintain cognitive functioning.

PMID: 29895218 [PubMed - indexed for MEDLINE]

Altered spatial and temporal concordance among intrinsic brain activity measures in schizophrenia.

Wed, 10/10/2018 - 15:00
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Altered spatial and temporal concordance among intrinsic brain activity measures in schizophrenia.

J Psychiatr Res. 2018 Oct 03;106:91-98

Authors: Zhu J, Zhu DM, Qian Y, Li X, Yu Y

Abstract
Various data-driven voxel-wise measures derived from resting-state functional magnetic resonance imaging (rs-fMRI) have been developed to characterize spontaneous brain activity. These measures have been widely applied to explore brain functional changes in schizophrenia and have enjoyed significant success in unraveling the neural mechanisms of this disorder. However, their spatial and temporal coupling alterations in schizophrenia remain largely unknown. To address this issue, 88 schizophrenia patients and 116 gender- and age-matched healthy controls underwent rs-fMRI examinations. Kendall's W was used to calculate volume-wise (across voxels) and voxel-wise (across time windows) concordance among multiple commonly used measures, including fractional amplitude of low frequency fluctuations, regional homogeneity, voxel-mirrored homotopic connectivity, degree centrality and global signal connectivity. Inter-group differences in the concordance were investigated. Results revealed that whole gray matter volume-wise concordance was reduced in schizophrenia patients relative to healthy controls. Although two groups showed similar spatial distributions of the voxel-wise concordance, quantitative comparison analysis revealed that schizophrenia patients exhibited decreased voxel-wise concordance in gray matter areas spanning the bilateral frontal, parietal, occipital, temporal and insular cortices. In addition, these concordance changes were negatively correlated with onset age in schizophrenia patients. Our findings suggest that the concordance approaches may provide new insights into the neural mechanisms of schizophrenia and have the potential to be extended to neuropsychiatric disorders.

PMID: 30300826 [PubMed - as supplied by publisher]

A framework for linking resting-state chronnectome/genome features in schizophrenia: A pilot study.

Wed, 10/10/2018 - 15:00
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A framework for linking resting-state chronnectome/genome features in schizophrenia: A pilot study.

Neuroimage. 2018 Oct 06;:

Authors: Rashid B, Chen J, Rashid I, Damaraju E, Liu J, Miller R, Agcaoglu O, van Erp TGM, Lim KO, Turner JA, Mathalon DH, Ford JM, Voyvodic J, Mueller BA, Belger A, McEwen S, Potkin SG, Preda A, Bustillo JR, Pearlson GD, Calhoun VD

Abstract
Multimodal, imaging-genomics techniques offer a platform for understanding genetic influences on brain abnormalities in psychiatric disorders. Such approaches utilize the information available from both imaging and genomics data and identify their association. Particularly for complex disorders such as schizophrenia, the relationship between imaging and genomic features may be better understood by incorporating additional information provided by advanced multimodal modeling. In this study, we propose a novel framework to combine features corresponding to functional magnetic resonance imaging (functional) and single nucleotide polymorphism (SNP) data from 61 schizophrenia (SZ) patients and 87 healthy controls (HC). In particular, the features for the functional and genetic modalities include dynamic (i.e., time-varying) functional network connectivity (dFNC) features and the SNP data, respectively. The dFNC features are estimated from component time-courses, obtained using group independent component analysis (ICA), by computing sliding-window functional network connectivity, and then estimating subject specific states from this dFNC data using a k-means clustering approach. For each subject, both the functional (dFNC states) and SNP data are selected as features for a parallel ICA (pICA) based imaging-genomic framework. This analysis identified a significant association between a SNP component (defined by large clusters of functionally related SNPs statistically correlated with phenotype components) and time-varying or dFNC component (defined by clusters of related connectivity links among distant brain regions distributed across discrete dynamic states, and statistically correlated with genomic components) in schizophrenia. Importantly, the polygenetic risk score (PRS) for SZ (computed as a linearly weighted sum of the genotype profiles with weights derived from the odds ratios of the psychiatric genomics consortium (PGC)) was negatively correlated with the significant dFNC component, which were mostly present within a state that exhibited a lower occupancy rate in individuals with SZ compared with HC, hence identifying a potential dFNC imaging biomarker for schizophrenia. Taken together, the current findings provide preliminary evidence for a link between dFNC measures and genetic risk, suggesting the application of dFNC patterns as biomarkers in imaging genetic association study.

PMID: 30300752 [PubMed - as supplied by publisher]

Advantages of Short Repetition Time Resting-State Functional MRI Enabled by Simultaneous Multi-slice Imaging.

Wed, 10/10/2018 - 15:00
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Advantages of Short Repetition Time Resting-State Functional MRI Enabled by Simultaneous Multi-slice Imaging.

J Neurosci Methods. 2018 Oct 06;:

Authors: Jahanian H, Holdsworth S, Christen T, Wu H, Zhu K, Kerr AB, Middione MJ, Dougherty RF, Moseley M, Zaharchuk G

Abstract
BACKGROUND: Recent advancements in simultaneous multi-slice (SMS) imaging techniques have enabled whole-brain resting-state fMRI (rs-fMRI) scanning at sub-second temporal resolution, providing spectral ranges much wider than the typically used range of 0.01-0.1 Hz. However, the advantages of this accelerated acquisition for rs-fMRI have not been evaluated.
NEW METHOD: In this study, we used SMS Echo Planar Imaging (EPI) to probe whole-brain functional connectivity with a short repetition time (TR = 350 ms) and compared it with standard EPI with a longer TR of 2000 ms. We determined the effect of scan length and investigated the temporal filtration strategies that optimize results based on metrics of signal-noise separation and test-retest reliability using both seed-based and independent component analysis (ICA).
RESULTS: We found that use of either the entire frequency range of 0.01-1.4 Hz or the entire frequency range with the exclusion of typical cardiac and respiratory frequency values tended to provide the best functional connectivity maps.
COMPARISON WITH EXISTING METHODS: We found that the SMS-acquired rs-fMRI scans had improved the signal-noise separation, while preserving the same level of test-retest reliability compared to conventional EPI, and enabled the detection of reliable functional connectivity networks with scan times as short as 3 minutes.
CONCLUSIONS: Our findings suggest that whole-brain rs-fMRI studies may benefit from the increased temporal resolution enabled by the SMS-EPI acquisition, leading to drastic scan time reductions, which in turn should enable the more widespread use of rs-fMRI in clinical research protocols.

PMID: 30300699 [PubMed - as supplied by publisher]

Modulatory Effects of Levodopa on Cerebellar Connectivity in Parkinson's Disease.

Wed, 10/10/2018 - 15:00
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Modulatory Effects of Levodopa on Cerebellar Connectivity in Parkinson's Disease.

Cerebellum. 2018 Oct 08;:

Authors: Mueller K, Jech R, Ballarini T, Holiga Š, Růžička F, Piecha FA, Möller HE, Vymazal J, Růžička E, Schroeter ML

Abstract
Levodopa has been the mainstay of symptomatic therapy for Parkinson's disease (PD) for the last five decades. However, it is associated with the development of motor fluctuations and dyskinesia, in particular after several years of treatment. The aim of this study was to shed light on the acute brain functional reorganization in response to a single levodopa dose. Functional magnetic resonance imaging (fMRI) was performed after an overnight withdrawal of dopaminergic treatment and 1 h after a single dose of 250 mg levodopa in a group of 24 PD patients. Eigenvector centrality was calculated in both treatment states using resting-state fMRI. This offers a new data-driven and parameter-free approach, similar to Google's PageRank algorithm, revealing brain connectivity alterations due to the effect of levodopa treatment. In all PD patients, levodopa treatment led to an improvement of clinical symptoms as measured with the Unified Parkinson's Disease Rating Scale motor score (UPDRS-III). This therapeutic effect was accompanied with a major connectivity increase between cerebellar brain regions and subcortical areas of the motor system such as the thalamus, putamen, globus pallidus, and brainstem. The degree of interconnectedness of cerebellar regions correlated with the improvement of clinical symptoms due to the administration of levodopa. We observed significant functional cerebellar connectivity reorganization immediately after a single levodopa dose in PD patients. Enhanced general connectivity (eigenvector centrality) was associated with better motor performance as assessed by UPDRS-III score. This underlines the importance of considering cerebellar networks as therapeutic targets in PD.

PMID: 30298443 [PubMed - as supplied by publisher]

Altered brain functional network in children with type 1 Gaucher disease: a longitudinal graph theory-based study.

Wed, 10/10/2018 - 15:00
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Altered brain functional network in children with type 1 Gaucher disease: a longitudinal graph theory-based study.

Neuroradiology. 2018 Oct 08;:

Authors: Zhang M, Wang S, Hu D, Kang H, Ouyang M, Zhang Y, Rao B, Huang H, Peng Y

Abstract
PURPOSE: Previous studies have investigated the brain structural abnormalities in children with type I Gaucher disease (GD). The purpose of our study is to investigate the topological efficiency of the brain functional network in children with type 1 GD.
METHODS: Twenty-two children diagnosed with type 1 GD and 22 sex- and age-matched healthy controls (HCs) underwent resting-state functional MRI (rs-fMRI) examination. For longitudinal study, the GD patients underwent rs-fMRI examination again after 4.6 years. Graph theoretical analysis was used to assess the brain network topological properties at the global and regional levels.
RESULTS: Compared with the HCs, the children with type 1 GD showed a decreased efficiency in functional segregation with a decreased γ (normalized clustering coefficient). In addition, the balance between functional segregation and integration was disrupted with decreased small-worldness (σ). At the regional level, the children with type 1 GD showed significantly decreased nodal degree and efficiency in the right precentral gyrus (PreCG.R) and left postcentral gyrus (PoCG.L). The significantly altered γ, σ, and nodal degree in the PreCG.R and PoCG.L were negatively correlated with the disease duration. No significant alterations in the global and regional topological properties were identified in these patients over time.
CONCLUSION: Compared with that of the HCs, the efficiency of the brain functional network in the children with type 1 GD was disrupted, and regional involvement was located in motor- and sensory-related regions. The efficiency of the brain functional network in these patients remained stable over time.

PMID: 30298188 [PubMed - as supplied by publisher]

The Combination of Functional and Structural MRI Is a Potential Screening Tool in Alzheimer's Disease.

Wed, 10/10/2018 - 15:00
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The Combination of Functional and Structural MRI Is a Potential Screening Tool in Alzheimer's Disease.

Front Aging Neurosci. 2018;10:251

Authors: Huang CC, Huang WM, Chen CH, Jhou ZY, The Alzheimer's Disease Neuroimaging Initiative, Lin CP

Abstract
Introduction: This study aimed to survey the discrimination power of parameters from cerebrospinal fluid (CSF) biomarkers, fluorodeoxyglucose uptake on PET (FDG-PET), structural magnetic resonance imaging (MRI), and functional MRI in high- and low-risk subjects or in converters and stable subjects of normal and mild cognitive impairment (MCI) statuses. Methods: We used baseline resting-state functional MRI (rfMRI) from the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset to analyze functional networks and recorded subjects' characteristics and results of the CSF study, FDG-PET, and structural MRI from the ADNI website. All parameters were evaluated based on the between-group difference among normal (NC), MCI, and Alzheimer's disease (AD) groups. The parameters other than CSF results were included to study the difference between high- and low-AD-risk subjects in NC or MCI groups, based on CSF results. On the basis of two-year follow-up conditions, all parameters were compared between stable subjects and converters in NC and MCI. Results: CSF biomarkers, FDG-PET, structural MRI, and functional MRI are all able to differentiate AD from MCI or NC but not between MCI and NC. As compared with low-AD-risk subjects, high-risk subjects present decreased FDG-PET in both MCI and NC groups but structural MRI change only in MCI status and rfMRI alteration only in NC status. As compared with stable subjects, converters have decreased FDG-PET, functional network changes, and structural changes in both MCI and NC groups. Conclusion: The combination of functional and structural MRI is a safer screening tool but with similar power as FDG-PET to reflect CSF change in the AD pathological process and to identify high-risk subjects and converters in NC and MCI.

PMID: 30297997 [PubMed]

Intranasal oxytocin in rhesus monkeys alters brain networks that detect social salience and reward.

Tue, 10/09/2018 - 13:40
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Intranasal oxytocin in rhesus monkeys alters brain networks that detect social salience and reward.

Am J Primatol. 2018 Sep 17;:e22915

Authors: Parr LA, Mitchell T, Hecht E

Abstract
In primates, resting state functional neuroimaging (rsfcMRI) has identified several large-scale, intrinsic brain networks, including the salience network (SN), which is involved in detecting stimulus salience. Intranasal oxytocin (IN-OT) has been shown to modulate the salience and rewarding quality of social stimuli in mammals and numerous studies have shown that it can affect the functional connectivity between brain regions. Less is known, however, about how these effects unfold over time following IN-OT administration. This study used rsfcMRI in anesthetized rhesus macaques to track temporal changes in the functional connectivity between brain regions involved in the SN, including the anterior cingulate cortex (ACC), anterior insula (AI), amygdala (amy), and ventral striatum (vstr), lasting 3 hr after IN-OT or Placebo (saline) administration. We found significant temporal changes in the functional connectivity between all regions associated with treatment condition. IN-OT increased the functional connectivity between AI_vstr, ACC_amy (right hemisphere), ACC_vstr (left hemisphere), and amy_vstr (right hemisphere), but reduced the functional connectivity between ACC_AI, and the AI_amygdala. These results suggest that IN-OT may dampen salience detection in rhesus monkeys, consistent with previous findings of reduced social vigilance, while enhancing the connectivity between the SN and regions involved in processing reward.

PMID: 30295946 [PubMed - as supplied by publisher]

Cluster analysis with MOODS-SR illustrates a potential bipolar disorder risk phenotype in young adults with remitted major depressive disorder.

Tue, 10/09/2018 - 13:40
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Cluster analysis with MOODS-SR illustrates a potential bipolar disorder risk phenotype in young adults with remitted major depressive disorder.

Bipolar Disord. 2018 Oct 07;:

Authors: Kling LR, Bessette KL, DelDonno SR, Ryan KA, Drevets WC, McInnis MG, Phillips ML, Langenecker SA

Abstract
OBJECTIVES: Delays in the diagnosis and detection of bipolar disorder can lead to adverse consequences, including improper treatment and increased suicide risk. The Mood Spectrum Self-Report Measure (MOODS-SR) was designed to capture the full spectrum of lifetime mood symptomology with factor scores for depression and mania symptom constellations. The utility of the MOODS-SR as a tool to investigate homogeneous subgroups was examined, with particular focus on a possible bipolar risk subgroup. Moreover, potential patterns of differences in MOODS-SR subtypes were probed using cognitive vulnerabilities, neuropsychological functioning, and ventral striatum connectivity.
METHODS: K-mean cluster analysis based on factor scores of MOODS-SR was used to determine homogeneous subgroupings within a healthy and remitted depressed young adult sample (N = 86). Between-group comparisons (based on cluster subgroupings) were conducted on measures of cognitive vulnerabilities, neuropsychological functioning, and ventral striatum rs-fMRI connectivity.
RESULTS: Three groups of participants were identified: one with minimal symptomology, one with moderate primarily depressive symptomology, and one with more severe manic and depressive symptomology. Differences in impulsivity, neuroticism, conscientiousness, facial perception accuracy, and rs-fMRI connectivity exist between moderate and severe groups.
CONCLUSIONS: Within a sample of people with and without depression histories, a severe subgroup was identified with potentially increased risk of developing bipolar disorder through use of the MOODS-SR. This small subgroup had higher levels of lifetime depression and mania symptoms. Additionally, differences in traits, affective processing, and connectivity exist between those with a more prototypic unipolar subgrouping and those with potential risk for developing bipolar disorder.

PMID: 30294823 [PubMed - as supplied by publisher]

Functional connectome of the five-factor model of personality.

Tue, 10/09/2018 - 13:40
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Functional connectome of the five-factor model of personality.

Personal Neurosci. 2018;1:

Authors: Toschi N, Riccelli R, Indovina I, Terracciano A, Passamonti L

Abstract
A key objective of the emerging field of personality neuroscience is to link the great variety of the enduring dispositions of human behaviour with reliable markers of brain function. This can be achieved by analyzing large sets of data with methods that model whole-brain connectivity patterns. To meet these expectations, we exploited a large repository of personality and neuroimaging measures made publicly available via the Human Connectome Project. Using connectomic analyses based on graph theory, we computed global and local indices of functional connectivity (e.g., nodal strength, efficiency, clustering, betweenness centrality) and related these metrics to the five-factor-model (FFM) personality traits (i.e., neuroticism, extraversion, openness, agreeableness, and conscientiousness). The maximal information coefficient was used to assess for linear and non-linear statistical dependencies across the graph 'nodes', which were defined as distinct brain circuits identified via independent component analysis. Multi-variate regression models and 'train/test' machine-learning approaches were also used to examine the associations between FFM traits and connectomic indices as well as to test for the generalizability of the main findings, whilst accounting for age and sex differences. Conscientiousness was the sole FFM trait linked to measures of higher functional connectivity in the fronto-parietal and default mode networks. This might provide a mechanistic explanation of the behavioural observation that conscientious people are reliable and efficient in goal-setting or planning. Our study provides new inputs to understanding the neurological basis of personality and contributes to the development of more realistic models of the brain dynamics that mediate personality differences.

PMID: 30294715 [PubMed]

Catecholaminergic manipulation alters dynamic network topology across cognitive states.

Tue, 10/09/2018 - 13:40
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Catecholaminergic manipulation alters dynamic network topology across cognitive states.

Netw Neurosci. 2018;2(3):381-396

Authors: Shine JM, van den Brink RL, Hernaus D, Nieuwenhuis S, Poldrack RA

Abstract
The human brain is able to flexibly adapt its information processing capacity to meet a variety of cognitive challenges. Recent evidence suggests that this flexibility is reflected in the dynamic reorganization of the functional connectome. The ascending catecholaminergic arousal systems of the brain are a plausible candidate mechanism for driving alterations in network architecture, enabling efficient deployment of cognitive resources when the environment demands them. We tested this hypothesis by analyzing both resting-state and task-based fMRI data following the administration of atomoxetine, a noradrenaline reuptake inhibitor, compared with placebo, in two separate human fMRI studies. Our results demonstrate that the manipulation of central catecholamine levels leads to a reorganization of the functional connectome in a manner that is sensitive to ongoing cognitive demands.

PMID: 30294705 [PubMed]

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