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https://www.readbyqxmd.com/read/29475076/from-percept-to-concept-in-the-ventral-temporal-lobes-graded-hemispheric-specialisation-based-on-stimulus-and-task
#1
Paul Hoffman, Matthew A Lambon Ralph
The left and right ventral anterior temporal lobes (vATL) have been implicated as key regions for the representation of conceptual knowledge. However, the nature and degree of hemispheric specialisation in their function is unclear. To address this issue, we investigated hemispheric specialisation in the ventral temporal lobes using a distortion-corrected spin-echo fMRI protocol that enhanced signal in vATL. We employed an orthogonal manipulation of stimulus (written words vs pictured objects) and task (naming vs recognition)...
February 2, 2018: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
https://www.readbyqxmd.com/read/29471100/dynamic-fmri-networks-predict-success-in-a-behavioral-weight-loss-program-among-older-adults
#2
Fatemeh Mokhtari, W Jack Rejeski, Yingying Zhu, Guorong Wu, Sean L Simpson, Jonathan H Burdette, Paul J Laurienti
More than one-third of adults in the United States are obese, with a higher prevalence among older adults. Obesity among older adults is a major cause of physical dysfunction, hypertension, diabetes, and coronary heart diseases. Many people who engage in lifestyle weight loss interventions fail to reach targeted goals for weight loss, and most will regain what was lost within 1-2 years following cessation of treatment. This variability in treatment efficacy suggests that there are important phenotypes predictive of success with intentional weight loss that could lead to tailored treatment regimen, an idea that is consistent with the concept of precision-based medicine...
February 19, 2018: NeuroImage
https://www.readbyqxmd.com/read/29462767/psychosocial-and-neural-indicators-of-resilience-among-youth-with-a-family-history-of-substance-use-disorder
#3
Meghan E Martz, Robert A Zucker, John E Schulenberg, Mary M Heitzeg
BACKGROUND: Little is known regarding the combined influence of psychosocial and neural protective mechanisms against substance use. The present study examined the extent to which neuroimaging measures of disinhibition predicted resilience against binge drinking and marijuana use among youth with a family history of substance use disorder (SUD; FH+), accounting for psychosocial measures of behavioral control. METHODS: Participants were 57 FH+ youth from the Michigan Longitudinal Study categorized into resilient and high-risk groups based on patterns of weekly binge drinking and monthly marijuana use during early adulthood...
February 11, 2018: Drug and Alcohol Dependence
https://www.readbyqxmd.com/read/29457314/latent-source-mining-in-fmri-via-restricted-boltzmann-machine
#4
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/29454105/assessing-the-repeatability-of-absolute-cmro-2-oef-and-haemodynamic-measurements-from-calibrated-fmri
#5
Alberto Merola, Michael A Germuska, Kevin Murphy, Richard G Wise
As energy metabolism in the brain is largely oxidative, the measurement of cerebral metabolic rate of oxygen consumption (CMRO 2 ) is a desirable biomarker for quantifying brain activity and tissue viability. Currently, PET techniques based on oxygen isotopes are the gold standard for obtaining whole brain CMRO 2 maps. Among MRI techniques that have been developed as an alternative are dual calibrated fMRI (dcFMRI) methods, which exploit simultaneous measurements of BOLD and ASL signals during a hypercapnic-hyperoxic experiment to modulate brain blood flow and oxygenation...
February 14, 2018: NeuroImage
https://www.readbyqxmd.com/read/29454104/functional-brain-connectivity-is-predictable-from-anatomic-network-s-laplacian-eigen-structure
#6
Farras Abdelnour, Michael Dayan, Orrin Devinsky, Thomas Thesen, Ashish Raj
How structural connectivity (SC) gives rise to functional connectivity (FC) is not fully understood. Here we mathematically derive a simple relationship between SC measured from diffusion tensor imaging, and FC from resting state fMRI. We establish that SC and FC are related via (structural) Laplacian spectra, whereby FC and SC share eigenvectors and their eigenvalues are exponentially related. This gives, for the first time, a simple and analytical relationship between the graph spectra of structural and functional networks...
February 14, 2018: NeuroImage
https://www.readbyqxmd.com/read/29452265/characterizing-the-modulation-of-resting-state-fmri-metrics-by-baseline-physiology
#7
Powell P W Chu, Ali M Golestani, Jonathan B Kwinta, Yasha B Khatamian, J Jean Chen
The blood-oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) signal is commonly used to assess functional connectivity across brain regions, particularly in the resting state (rs-fMRI). However, the BOLD fMRI signal is not merely a representation of neural activity, but a combination of neural activity and vascular response. These aspects of the BOLD signal are easily influenced by systemic physiology, potentially biasing BOLD-based functional connectivity measurements. In this work, we focus on the following physiological modulators of the BOLD signal: cerebral blood flow (CBF), venous blood oxygenation, and cerebrovascular reactivity (CVR)...
February 13, 2018: NeuroImage
https://www.readbyqxmd.com/read/29450932/cardiorespiratory-noise-correction-improves-the-asl-signal
#8
Mahlega S Hassanpour, Qingfei Luo, W Kyle Simmons, Justin S Feinstein, Martin P Paulus, Wen-Ming Luh, Jerzy Bodurka, Sahib S Khalsa
Cardiorespiratory fluctuations such as changes in heart rate or respiration volume influence the temporal dynamics of cerebral blood flow (CBF) measurements during arterial spin labeling (ASL) fMRI. This "physiological noise" can confound estimates of resting state network activity, and it may lower the signal-to-noise ratio of ASL during task-related experiments. In this study we examined several methods for minimizing the contributions of both synchronized and non-synchronized physiological noise in ASL measures of CBF, by combining the RETROICOR approach with different linear deconvolution models...
February 15, 2018: Human Brain Mapping
https://www.readbyqxmd.com/read/29448074/a-probabilistic-approach-to-discovering-dynamic-full-brain-functional-connectivity-patterns
#9
REVIEW
Jeremy R Manning, Xia Zhu, Theodore L Willke, Rajesh Ranganath, Kimberly Stachenfeld, Uri Hasson, David M Blei, Kenneth A Norman
Recent research shows that the covariance structure of functional magnetic resonance imaging (fMRI) data - commonly described as functional connectivity - can change as a function of the participant's cognitive state (for review see (Turk-Browne, 2013)). Here we present a Bayesian hierarchical matrix factorization model, termed hierarchical topographic factor analysis (HTFA), for efficiently discovering full-brain networks in large multi-subject neuroimaging datasets. HTFA approximates each subject's network by first re-representing each brain image in terms of the activities of a set of localized nodes, and then computing the covariance of the activity time series of these nodes...
February 12, 2018: NeuroImage
https://www.readbyqxmd.com/read/29434570/perspectives-on-how-human-simultaneous-multi-modal-imaging-adds-directionality-to-spread-models-of-alzheimer-s-disease
#10
Julia Neitzel, Rachel Nuttall, Christian Sorg
Previous animal research suggests that the spread of pathological agents in Alzheimer's disease (AD) follows the direction of signaling pathways. Specifically, tau pathology has been suggested to propagate in an infection-like mode along axons, from transentorhinal cortices to medial temporal lobe cortices and consequently to other cortical regions, while amyloid-beta (Aβ) pathology seems to spread in an activity-dependent manner among and from isocortical regions into limbic and then subcortical regions. These directed connectivity-based spread models, however, have not been tested directly in AD patients due to the lack of an in vivo method to identify directed connectivity in humans...
2018: Frontiers in Neurology
https://www.readbyqxmd.com/read/29431647/neural-mechanisms-for-adaptive-learned-avoidance-of-mental-effort
#11
Asako Mitsuto Nagase, Keiichi Onoda, Jerome Clifford Foo, Tomoki Haji, Rei Akaishi, Shuhei Yamaguchi, Katsuyuki Sakai, Kenji Morita
Humans tend to avoid mental effort. Previous studies have demonstrated this tendency using various demand-selection tasks; participants generally avoid options associated with higher cognitive demand. However, it remains unclear whether humans avoid mental effort adaptively in uncertain and non-stationary environments, and if so, what neural mechanisms underlie this learned avoidance and whether they remain the same irrespective of cognitive-demand types. We addressed these issues by developing novel demand-selection tasks where associations between choice options and cognitive-demand levels change over time, with two variations using mental arithmetic and spatial reasoning problems (29:4 and 18:2 males:females)...
February 5, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/29430573/learning-based-estimation-of-functional-correlation-tensors-in-white-matter-for-early-diagnosis-of-mild-cognitive-impairment
#12
Lichi Zhang, Han Zhang, Xiaobo Chen, Qian Wang, Pew-Thian Yap, Dinggang Shen
It has been recently demonstrated that the local BOLD signals in resting-state fMRI (rs-fMRI) can be captured for the white matter (WM) by functional correlation tensors (FCTs). FCTs provide similar orientation information as diffusion tensors (DTs), and also functional information concerning brain dynamics. However, FCTs are susceptible to noise due to the low signal-to-noise ratio nature of WM BOLD signals. Here we introduce a robust FCT estimation method to facilitate individualized diagnosis. First, we develop a noise-tolerating patch-based approach to measure spatiotemporal correlations of local BOLD signals...
September 2017: Patch-Based Techniques in Medical Imaging: Third International Workshop, Patch-MI 2017, Held in Conjunction with MICCAI 2017, Quebec City, QC, Canada, September 14, 2017, Proceedings
https://www.readbyqxmd.com/read/29428062/brad-software-for-brain-activity-detection-from-hemodynamic-response
#13
Anna Pidnebesna, David Tomeček, Jaroslav Hlinka
BACKGROUND AND OBJECTIVE: Precise estimation of neuronal activity from neuroimaging data is one of the central challenges of the application of noninvasive neuroimaging methods. One of the widely used methods for studying brain activity is functional magnetic resonance imaging, which is a neuroimaging procedure that measures brain activity based on the blood oxygenation level dependent effect. The blood oxygenation level dependent signal can be modeled as a linear convolution of a hemodynamic response function with an input signal corresponding to the neuronal activity...
March 2018: Computer Methods and Programs in Biomedicine
https://www.readbyqxmd.com/read/29427393/dynamic-2d-self-phase-map-nyquist-ghost-correction-for-simultaneous-multi-slice-echo-planar-imaging
#14
Uten Yarach, Yi-Hang Tung, Kawin Setsompop, Myung-Ho In, Itthi Chatnuntawech, Renat Yakupov, Frank Godenschweger, Oliver Speck
PURPOSE: To develop a reconstruction pipeline that intrinsically accounts for both simultaneous multislice echo planar imaging (SMS-EPI) reconstruction and dynamic slice-specific Nyquist ghosting correction in time-series data. METHODS: After 1D slice-group average phase correction, the separate polarity (i.e., even and odd echoes) SMS-EPI data were unaliased by slice GeneRalized Autocalibrating Partial Parallel Acquisition. Both the slice-unaliased even and odd echoes were jointly reconstructed using a model-based framework, extended for SMS-EPI reconstruction that estimates a 2D self-phase map, corrects dynamic slice-specific phase errors, and combines data from all coils and echoes to obtain the final images...
February 9, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29413764/comparison-of-two-mathematical-models-of-cellularity-calculation
#15
Hans Jonas Meyer, Nikita Garnov, Alexey Surov
OBJECT: Nowadays, there is increasing evidence that functional magnetic resonance imaging (MRI) modalities, namely, diffusion-weighted imaging (DWI) and dynamic-contrast enhanced MRI (DCE MRI), can characterize tumor architecture like cellularity and vascularity. Previously, two formulas based on a logistic tumor growth model were proposed to predict tumor cellularity with DWI and DCE. The purpose of this study was to proof these formulas. METHODS: 16 patients with head and neck squamous cell carcinomas were included into the study...
February 2, 2018: Translational Oncology
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
#16
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/29408607/functional-mri-in-prenatally-opioid-exposed-children-during-a-working-memory-selective-attention-task
#17
Eivind Sirnes, Silja T Griffiths, Stein Magnus Aukland, Geir Egil Eide, Irene B Elgen, Hilde Gundersen
BACKGROUND: Opioid induced cerebral changes may contribute to neuropsychological difficulties, like attention problems, frequently reported in prenatally opioid-exposed children. Reduced regional brain volumes have been shown after prenatal opioid exposure, but no study to date has explored the possible impact of prenatal opioids on brain activation patterns. MATERIALS AND METHODS: A hospital-based sample of prenatally opioid-exposed school-aged children (n = 11) and unexposed controls (n = 12) underwent functional magnetic resonance imaging (fMRI) during a combined working memory-selective attention task...
February 1, 2018: Neurotoxicology and Teratology
https://www.readbyqxmd.com/read/29408524/dissociating-neural-variability-related-to-stimulus-quality-and-response-times-in-perceptual-decision-making
#18
Stefan Bode, Daniel Bennett, David K Sewell, Bryan Paton, Gary F Egan, Philip L Smith, Carsten Murawski
According to sequential sampling models, perceptual decision-making is based on accumulation of noisy evidence towards a decision threshold. The speed with which a decision is reached is determined by both the quality of incoming sensory information and random trial-by-trial variability in the encoded stimulus representations. To investigate those decision dynamics at the neural level, participants made perceptual decisions while functional magnetic resonance imaging (fMRI) was conducted. On each trial, participants judged whether an image presented under conditions of high, medium, or low visual noise showed a piano or a chair...
February 1, 2018: Neuropsychologia
https://www.readbyqxmd.com/read/29398359/ultra-slow-single-vessel-bold-and-cbv-based-fmri-spatiotemporal-dynamics-and-their-correlation-with-neuronal-intracellular-calcium-signals
#19
Yi He, Maosen Wang, Xuming Chen, Rolf Pohmann, Jonathan R Polimeni, Klaus Scheffler, Bruce R Rosen, David Kleinfeld, Xin Yu
Functional MRI has been used to map brain activity and functional connectivity based on the strength and temporal coherence of neurovascular-coupled hemodynamic signals. Here, single-vessel fMRI reveals vessel-specific correlation patterns in both rodents and humans. In anesthetized rats, fluctuations in the vessel-specific fMRI signal are correlated with the intracellular calcium signal measured in neighboring neurons. Further, the blood-oxygen-level-dependent (BOLD) signal from individual venules and the cerebral-blood-volume signal from individual arterioles show correlations at ultra-slow (<0...
January 26, 2018: Neuron
https://www.readbyqxmd.com/read/29397900/neural-mechanisms-of-early-life-social-stress-as-a-developmental-risk-factor-for-severe-psychiatric-disorders
#20
Jonathan Rochus Reinwald, Robert Becker, Anne Stephanie Mallien, Claudia Falfan-Melgoza, Markus Sack, Christian Clemm von Hohenberg, Urs Braun, Alejandro Cosa Linan, Natalia Gass, Andrei-Nicolae Vasilescu, Fabian Tollens, Philipp Lebhardt, Natascha Pfeiffer, Dragos Inta, Andreas Meyer-Lindenberg, Peter Gass, Alexander Sartorius, Wolfgang Weber-Fahr
BACKGROUND: To explore the domain-general risk factor of early-life social stress in mental illness, rearing rodents in persistent postweaning social isolation has been established as a widely used animal model with translational relevance for neurodevelopmental psychiatric disorders such as schizophrenia. Although changes in resting-state brain connectivity are a transdiagnostic key finding in neurodevelopmental diseases, a characterization of imaging correlates elicited by early-life social stress is lacking...
December 28, 2017: Biological Psychiatry
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