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https://www.readbyqxmd.com/read/29457314/latent-source-mining-in-fmri-via-restricted-boltzmann-machine
#1
Xintao Hu, Heng Huang, Bo Peng, Junwei Han, Nian Liu, Jinglei Lv, Lei Guo, Christine Guo, Tianming Liu
Blind source separation (BSS) is commonly used in functional magnetic resonance imaging (fMRI) data analysis. Recently, BSS models based on restricted Boltzmann machine (RBM), one of the building blocks of deep learning models, have been shown to improve brain network identification compared to conventional single matrix factorization models such as independent component analysis (ICA). These models, however, trained RBM on fMRI volumes, and are hence challenged by model complexity and limited training set...
February 18, 2018: Human Brain Mapping
https://www.readbyqxmd.com/read/29448436/nonparametric-weighted-stochastic-block-models
#2
Tiago P Peixoto
We present a Bayesian formulation of weighted stochastic block models that can be used to infer the large-scale modular structure of weighted networks, including their hierarchical organization. Our method is nonparametric, and thus does not require the prior knowledge of the number of groups or other dimensions of the model, which are instead inferred from data. We give a comprehensive treatment of different kinds of edge weights (i.e., continuous or discrete, signed or unsigned, bounded or unbounded), as well as arbitrary weight transformations, and describe an unsupervised model selection approach to choose the best network description...
January 2018: Physical Review. E
https://www.readbyqxmd.com/read/29432569/sleep-quality-and-adolescent-default-mode-network-connectivity
#3
Sarah M Tashjian, Diane Goldenberg, Martin M Monti, Adriana Galván
Sleep suffers during adolescence and is related to academic, emotional and social behaviors. How this normative change relates to ongoing brain development remains unresolved. The default mode network (DMN), a large-scale brain network important for complex cognition and socioemotional processing, undergoes intra-network integration and inter-network segregation during adolescence. Using resting state functional connectivity and actigraphy over 14 days we examined correlates of naturalistic individual differences in sleep duration and quality in the DMN at rest in fifty-five human adolescents (ages 14-18)...
February 7, 2018: Social Cognitive and Affective Neuroscience
https://www.readbyqxmd.com/read/29430941/the-not-so-global-bold-signal
#4
Jacob Charles Wright Billings, Shella Dawn Keilholz
Global signal regression is a controversial processing step for resting state functional magnetic resonance imaging, partly because the source of the global blood oxygen level-dependent (BOLD) signal remains unclear. On the one hand, nuisance factors such as motion can readily introduce coherent BOLD changes across the whole brain. On the other hand, the global signal has been linked to neural activity and vigilance levels, suggesting that it contains important neurophysiological information and should not be discarded...
February 12, 2018: Brain Connectivity
https://www.readbyqxmd.com/read/29422088/associations-of-bcl-2-rs956572-genotype-groups-in-the-structural-covariance-network-in-early-stage-alzheimer-s-disease
#5
Chiung-Chih Chang, Ya-Ting Chang, Chi-Wei Huang, Shih-Jen Tsai, Shih-Wei Hsu, Shu-Hua Huang, Chen-Chang Lee, Wen-Neng Chang, Chun-Chung Lui, Chia-Yi Lien
BACKGROUND: Alzheimer's disease (AD) is a complex neurodegenerative disease, and genetic differences may mediate neuronal degeneration. In humans, a single-nucleotide polymorphism in the B-cell chronic lymphocytic leukemia/lymphoma-2 (Bcl-2) gene, rs956572, has been found to significantly modulate Bcl-2 protein expression in the brain. The Bcl-2 AA genotype has been associated with reduced Bcl-2 levels and lower gray matter volume in healthy populations. We hypothesized that different Bcl-2 genotype groups may modulate large-scale brain networks that determine neurobehavioral test scores...
February 8, 2018: Alzheimer's Research & Therapy
https://www.readbyqxmd.com/read/29416047/low-dose-x-ray-tomography-through-a-deep-convolutional-neural-network
#6
Xiaogang Yang, Vincent De Andrade, William Scullin, Eva L Dyer, Narayanan Kasthuri, Francesco De Carlo, Doğa Gürsoy
Synchrotron-based X-ray tomography offers the potential for rapid large-scale reconstructions of the interiors of materials and biological tissue at fine resolution. However, for radiation sensitive samples, there remain fundamental trade-offs between damaging samples during longer acquisition times and reducing signals with shorter acquisition times. We present a deep convolutional neural network (CNN) method that increases the acquired X-ray tomographic signal by at least a factor of 10 during low-dose fast acquisition by improving the quality of recorded projections...
February 7, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29414460/re-emergence-of-modular-brain-networks-in-stroke-recovery
#7
Joshua S Siegel, Benjamin A Seitzman, Lenny E Ramsey, Mario Ortega, Evan M Gordon, Nico U F Dosenbach, Steven E Petersen, Gordon L Shulman, Maurizio Corbetta
Studies of stroke have identified local reorganization in perilesional tissue. However, because the brain is highly networked, strokes also broadly alter the brain's global network organization. Here, we assess brain network structure longitudinally in adult stroke patients using resting state fMRI. The topology and boundaries of cortical regions remain grossly unchanged across recovery. In contrast, the modularity of brain systems i.e. the degree of integration within and segregation between networks, was significantly reduced sub-acutely (n = 107), but partially recovered by 3 months (n = 85), and 1 year (n = 67)...
January 5, 2018: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
https://www.readbyqxmd.com/read/29410486/the-energy-landscape-of-neurophysiological-activity-implicit-in-brain-network-structure
#8
Shi Gu, Matthew Cieslak, Benjamin Baird, Sarah F Muldoon, Scott T Grafton, Fabio Pasqualetti, Danielle S Bassett
A critical mystery in neuroscience lies in determining how anatomical structure impacts the complex functional dynamics of the brain. How does large-scale brain circuitry constrain states of neuronal activity and transitions between those states? We address these questions using a maximum entropy model of brain dynamics informed by white matter tractography. We demonstrate that the most probable brain states - characterized by minimal energy - display common activation profiles across brain areas: local spatially-contiguous sets of brain regions reminiscent of cognitive systems are co-activated frequently...
February 6, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29410136/pretherapeutic-functional-imaging-allows-prediction-of-head-tremor-arrest-after-thalamotomy-for-essential-tremor-the-role-of-altered-interconnectivity-between-thalamolimbic-and-supplementary-motor-circuits
#9
Constantin Tuleasca, Jean Régis, Elena Najdenovska, Tatiana Witjas, Nadine Girard, Jérôme Champoudry, Mohamed Faouzi, Jean-Philippe Thiran, Meritxell Bach Cuadra, Marc Levivier, Dimitri Van De Ville
OBJECTIVE: To correlate pretherapeutic resting-state functional MRI (rs-fMRI) measures with pretherapeutic head tremor presence and/or further improvement 1 year after stereotactic radiosurgical thalamotomy (SRS-T) for essential tremor (ET). METHODS: We prospectively collected head tremor scores (range 0-3) and rs-fMRI data for a cohort of 17 consecutive ET patients in pretherapeutic and 1 year after SRS-T states. We additionally acquired rs-fMRI data for a healthy control (HC) group (n=12)...
January 31, 2018: World Neurosurgery
https://www.readbyqxmd.com/read/29410103/frontoparietal-areas-link-impairments-of-large-scale-intrinsic-brain-networks-with-aberrant-fronto-striatal-interactions-in-ocd-a-meta-analysis-of-resting-state-functional-connectivity
#10
REVIEW
Deniz A Gürsel, Mihai Avram, Christian Sorg, Felix Brandl, Kathrin Koch
Neuroimaging studies report evidence for two distinct pathophysiological models of obsessive-compulsive disorder (OCD): disrupted fronto-striatal circuits and impaired large-scale fronto-parietal-limbic intrinsic brain networks, defined by functionally connected (FC) infra-slow oscillations in ongoing brain activity. To synthesize this literature and overcome inconsistencies, we conducted a coordinate-based meta-analysis of 18 whole-brain resting-state functional magnetic resonance imaging (fMRI) studies (541 patients, 572 healthy controls) comparing seed-based FC between OCD patients and healthy controls...
February 3, 2018: Neuroscience and Biobehavioral Reviews
https://www.readbyqxmd.com/read/29409683/neural-correlates-of-unconsciousness-in-large-scale-brain-networks
#11
REVIEW
George A Mashour, Anthony G Hudetz
The biological basis of consciousness is one of the most challenging and fundamental questions in 21st century science. A related pursuit aims to identify the neural correlates and causes of unconsciousness. We review current trends in the investigation of physiological, pharmacological, and pathological states of unconsciousness at the level of large-scale functional brain networks. We focus on the roles of brain connectivity, repertoire, graph-theoretical techniques, and neural dynamics in understanding the functional brain disconnections and reduced complexity that appear to characterize these states...
February 3, 2018: Trends in Neurosciences
https://www.readbyqxmd.com/read/29407457/cortical-parcellation-based-on-structural-connectivity-a-case-for-generative-models
#12
Marc Tittgemeyer, Lionel Rigoux, Thomas R Knösche
One of the major challenges in systems neuroscience is to identify brain networks and unravel their significance for brain function -this has led to the concept of the 'connectome'. Connectomes are currently extensively studied in large-scale international efforts at multiple scales, and follow different definitions with respect to their connections as well as their elements. Perhaps the most promising avenue for defining the elements of connectomes originates from the notion that individual brain areas maintain distinct (long-range) connection profiles...
January 30, 2018: NeuroImage
https://www.readbyqxmd.com/read/29399604/cognitive-motivational-interactions-beyond-boxes-and-arrows-models-of-the-mind-brain
#13
Luiz Pessoa
How do motivation and cognitive control interact in brain and behavior? The past decade has witnessed a steady growth in studies investigating both the behavioral and the brain basis of these interactions. In this paper, I describe such interactions in the context of the dual completion model, which proposes that motivational significance influences both perceptual and executive competition. Embracing a research agenda that attempts to understand cognition-motivation interactions highlights considerable challenges faced by investigators...
September 2017: Motivation Science
https://www.readbyqxmd.com/read/29398207/effective-connectivity-within-a-triple-network-brain-system-discriminates-schizophrenia-spectrum-disorders-from-psychotic-bipolar-disorder-at-the-single-subject-level
#14
Lena Palaniyappan, Gopikrishna Deshpande, Pradyumna Lanka, D Rangaprakash, Sarina Iwabuchi, Susan Francis, Peter F Liddle
OBJECTIVE: Schizophrenia spectrum disorders (SSD) and psychotic bipolar disorder share a number of genetic and neurobiological features, despite a divergence in clinical course and outcome trajectories. We studied the diagnostic classification potential that can be achieved on the basis of the structure and connectivity within a triple network system (the default mode, salience and central executive network) in patients with SSD and psychotic bipolar disorder. METHODS: Directed static connectivity and its dynamic variance was estimated among 8 nodes of the three large-scale networks...
February 2, 2018: Schizophrenia Research
https://www.readbyqxmd.com/read/29382543/coupling-and-segregation-of-large-scale-brain-networks-predict-individual-differences-in-delay-discounting
#15
Zhiyi Chen, Yiqun Guo, Tingyong Feng
Decision-making about rewards, which requires us to choose between different time points, generally refers to intertemporal choice. Converging evidence suggests that some of the brain networks recruited in the delay discounting task have been well characterized for intertemporal choice. However, little is known about how the connectivity patterns of these large-scale brain networks are associated with delay discounting. Here, we use a resting-state functional connectivity MRI (rs-fcMRI) and a graph theoretical analysis to address this question...
January 27, 2018: Biological Psychology
https://www.readbyqxmd.com/read/29381889/alteration-in-the-local-and-global-functional-connectivity-of-resting-state-networks-in-parkinson-s-disease
#16
Maryam Ghahremani, Jaejun Yoo, Sun Ju Chung, Kwangsun Yoo, Jong C Ye, Yong Jeong
OBJECTIVE: Parkinson's disease (PD) is a neurodegenerative disorder that mainly leads to the impairment of patients' motor function, as well as of cognition, as it progresses. This study tried to investigate the impact of PD on the resting state functional connectivity of the default mode network (DMN), as well as of the entire brain. METHODS: Sixty patients with PD were included and compared to 60 matched normal control (NC) subjects. For the local connectivity analysis, the resting state fMRI data were analyzed by seed-based correlation analyses, and then a novel persistent homology analysis was implemented to examine the connectivity from a global perspective...
January 2018: Journal of Movement Disorders
https://www.readbyqxmd.com/read/29378970/landau-ginzburg-theory-of-cortex-dynamics-scale-free-avalanches-emerge-at-the-edge-of-synchronization
#17
Serena di Santo, Pablo Villegas, Raffaella Burioni, Miguel A Muñoz
Understanding the origin, nature, and functional significance of complex patterns of neural activity, as recorded by diverse electrophysiological and neuroimaging techniques, is a central challenge in neuroscience. Such patterns include collective oscillations emerging out of neural synchronization as well as highly heterogeneous outbursts of activity interspersed by periods of quiescence, called "neuronal avalanches." Much debate has been generated about the possible scale invariance or criticality of such avalanches and its relevance for brain function...
January 29, 2018: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29378318/hyperedge-bundling-a-practical-solution-to-spurious-interactions-in-meg-eeg-source-connectivity-analyses
#18
Sheng H Wang, Muriel Lobier, Felix Siebenhühner, Tuomas Puoliväli, Satu Palva, J Matias Palva
Inter-areal functional connectivity (FC), neuronal synchronization in particular, is thought to constitute a key systems-level mechanism for coordination of neuronal processing and communication between brain regions. Evidence to support this hypothesis has been gained largely using invasive electrophysiological approaches. In humans, neuronal activity can be non-invasively recorded only with magneto- and electroencephalography (MEG/EEG), which have been used to assess FC networks with high temporal resolution and whole-scalp coverage...
January 26, 2018: NeuroImage
https://www.readbyqxmd.com/read/29376881/modeling-the-interaction-of-navigational-systems-in-a-reward-based-virtual-navigation%C3%A2-task
#19
Somayeh Raiesdana
Existence of allocentric and egocentric systems for human navigation, mediating spatial and response learning respectively, has been discussed so far. It is controversial whether navigational strategies and their underlying learning systems and, accordingly, the activation of their associate brain areas are independent/parallel or whether they functionally/causally interact in a competitive or in a cooperative manner to solve navigational tasks. Insights of neural networks involved in reward-based navigation attributed to individual involvement or interactions of learning systems were searched...
2018: Journal of Integrative Neuroscience
https://www.readbyqxmd.com/read/29376825/the-modulation-of-neural-gain-facilitates-a-transition-between-functional-segregation-and-integration-in-the-brain
#20
James M Shine, Matthew J Aburn, Michael Breakspear, Russell Poldrack
Cognitive function relies on a dynamic, context-sensitive balance between functional integration and segregation in the brain. Previous work has proposed that this balance is mediated by global fluctuations in neural gain by projections from ascending neuromodulatory nuclei. To test this hypothesis in silico, we studied the effects of neural gain on network dynamics in a model of large-scale neuronal dynamics. We found that increases in neural gain directed the network through an abrupt dynamical transition, leading to an integrated network topology that was maximal in frontoparietal 'rich club' regions...
January 29, 2018: ELife
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