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BOLD Mri

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https://www.readbyqxmd.com/read/29030974/dopamine-transporter-gene-methylation-is-associated-with-nucleus-accumbens-activation-during-reward-processing-in-healthy-but-not-alcohol-dependent-individuals
#1
Christine Muench, Corinde E Wiers, Carlos R Cortes, Reza Momenan, Falk W Lohoff
BACKGROUND: Alcohol's reinforcement is mediated by dopamine signaling in the ventral striatum, which is modulated by the dopamine transporter (DAT). We hypothesized that methylomic variation in the DAT gene (SLC6A3) affects DAT expression thus contributing to differences in brain reward circuitry in individuals with alcohol dependence (ALC). METHODS: Blood from 45 recently detoxified ALC and 45 healthy control (HC) individuals was used to assess DNA methylation across 5 functional regions of SLC6A3...
October 14, 2017: Alcoholism, Clinical and Experimental Research
https://www.readbyqxmd.com/read/29027094/multimodal-functional-neuroimaging-by-simultaneous-bold-fmri-and-fiber-optic-calcium-recordings-and-optogenetic-control
#2
REVIEW
Franziska Albers, Lydia Wachsmuth, Timo Mauritz van Alst, Cornelius Faber
Recent developments of optogenetic tools and fluorescence-based calcium recording techniques enable the manipulation and monitoring of neural circuits on a cellular level. Non-invasive imaging of brain networks, however, requires the application of methods such as blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI), which is commonly used for functional neuroimaging. While BOLD fMRI provides brain-wide non-invasive reading of the hemodynamic response, it is only an indirect measure of neural activity...
October 12, 2017: Molecular Imaging and Biology: MIB: the Official Publication of the Academy of Molecular Imaging
https://www.readbyqxmd.com/read/29024300/accounting-for-the-role-of-hematocrit-in-between-subject-variations-of-mri-derived-baseline-cerebral-hemodynamic-parameters-and-functional-bold-responses
#3
Feng Xu, Wenbo Li, Peiying Liu, Jun Hua, John J Strouse, James J Pekar, Hanzhang Lu, Peter C M van Zijl, Qin Qin
Baseline hematocrit fraction (Hct) is a determinant for baseline cerebral blood flow (CBF) and between-subject variation of Hct thus causes variation in task-based BOLD fMRI signal changes. We first verified in healthy volunteers (n = 12) that Hct values can be derived reliably from venous blood T1 values by comparison with the conventional lab test. Together with CBF measured using phase-contrast MRI, this noninvasive estimation of Hct, instead of using a population-averaged Hct value, enabled more individual determination of oxygen delivery (DO2 ), oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen (CMRO2 )...
October 11, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/29022116/two-dimensional-temporal-clustering-analysis-for-patients-with-epilepsy-detecting-epilepsy-related-information-in-eeg-fmri-concordant-discordant-and-spike-less-patients
#4
Danilo Maziero, Tonicarlo R Velasco, Carlos E G Salmon, Victoria L Morgan
EEG acquired simultaneously with fMRI (EEG-fMRI) is a multimodal method that has shown promise in mapping the seizure onset zone in patients with focal epilepsy. However, there are many instances when this method is unsuccessful or not applicable, and other data driven fMRI methods may be utilized. One such method is the two-dimensional temporal clustering analysis (2dTCA). In this study we compared the classic EEG-fMRI and 2dTCA performance in mapping regions related to the seizure onset region in 18 focal epilepsy patients (12 presenting interictal epileptiform discharges (IEDs), during EEG-fMRI acquisition) with Engel I or II surgical outcome...
October 11, 2017: Brain Topography
https://www.readbyqxmd.com/read/28971011/structurofunctional-resting-state-networks-correlate-with-motor-function-in-chronic-stroke
#5
Benjamin T Kalinosky, Reivian Berrios Barillas, Brian D Schmit
PURPOSE: Motor function and recovery after stroke likely rely directly on the residual anatomical connections in the brain and its resting-state functional connectivity. Both structural and functional properties of cortical networks after stroke are revealed using multimodal magnetic resonance imaging (MRI). Specifically, functional connectivity MRI (fcMRI) can extract functional networks of the brain at rest, while structural connectivity can be estimated from white matter fiber orientations measured with high angular-resolution diffusion imaging (HARDI)...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28967593/measurement-of-cerebrovascular-reactivity-as-blood-oxygen-level-dependent-magnetic-resonance-imaging-signal-response-to-a-hypercapnic-stimulus-in-mechanically-ventilated-patients
#6
Lashmi Venkatraghavan, Julien Poublanc, Jay S Han, Olivia Sobczyk, Casey Rozen, Kevin Sam, James Duffin, David J Mikulis, Joseph A Fisher
BACKGROUND: Impaired cerebrovascular reactivity (CVR) is an important prognostic marker of stroke. Most measures of CVR lack (1) a reproducible vasoactive stimulus and (2) a high time and spatial resolution measure of cerebral blood flow (CBF), particularly for mechanically ventilated patients. The aim of our study was to investigate the feasibility of measuring CVR using sequential gas delivery circuit and gas blender for precise targeting of end-tidal PCO2 (PetCO2), and blood oxygen level-dependent magnetic resonance imaging (BOLD-MRI) signal as a surrogate of CBF, in mechanically ventilated patients...
September 26, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/28966091/modulation-of-long-range-connectivity-patterns-via-frequency-specific-stimulation-of-human-cortex
#7
Christiane A Weinrich, John-Stuart Brittain, Magdalena Nowak, Reza Salimi-Khorshidi, Peter Brown, Charlotte J Stagg
There is increasing interest in how the phase of local oscillatory activity within a brain area determines the long-range functional connectivity of that area. For example, increasing convergent evidence from a range of methodologies suggests that beta (20 Hz) oscillations may play a vital role in the function of the motor system [1-5]. The "communication through coherence" hypothesis posits that the precise phase of coherent oscillations in network nodes is a determinant of successful communication between them [6, 7]...
October 9, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28963852/advanced-and-amplified-bold-fluctuations-in-high-grade-gliomas
#8
Lalit Gupta, Rakesh K Gupta, Alida A Postma, Prativa Sahoo, Pradeep K Gupta, Rana Patir, Sunita Ahlawat, Indrajit Saha, Walter H Backes
BACKGROUND: Glioma grade along with patient's age and general health are used for treatment planning and prognosis. PURPOSE: To characterize and quantify the spontaneous blood oxygen level-dependent (BOLD) fluctuations in gliomas using measures based on T2*-weighted signal time-series and to distinguish between high- and low-grade gliomas. STUDY TYPE: Retrospective. SUBJECTS: Twenty-one patients with high-grade and 13 patients with low-grade gliomas confirmed on histology were investigated...
September 30, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28959212/multiparametric-renal-magnetic-resonance-imaging-validation-interventions-and-alterations-in-chronic-kidney-disease
#9
Eleanor F Cox, Charlotte E Buchanan, Christopher R Bradley, Benjamin Prestwich, Huda Mahmoud, Maarten Taal, Nicholas M Selby, Susan T Francis
Background: This paper outlines a multiparametric renal MRI acquisition and analysis protocol to allow non-invasive assessment of hemodynamics (renal artery blood flow and perfusion), oxygenation (BOLD T2(*)), and microstructure (diffusion, T1 mapping). Methods: We use our multiparametric renal MRI protocol to provide (1) a comprehensive set of MRI parameters [renal artery and vein blood flow, perfusion, T1, T2(*), diffusion (ADC, D, D(*), fp), and total kidney volume] in a large cohort of healthy participants (127 participants with mean age of 41 ± 19 years) and show the MR field strength (1...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28948064/iterative-analysis-of-cerebrovascular-reactivity-dynamic-response-by-temporal-decomposition
#10
Christiaan Hendrik Bas van Niftrik, Marco Piccirelli, Oliver Bozinov, Athina Pangalu, Joseph A Fisher, Antonios Valavanis, Andreas R Luft, Michael Weller, Luca Regli, Jorn Fierstra
OBJECTIVE: To improve quantitative cerebrovascular reactivity (CVR) measurements and CO 2 arrival times, we present an iterative analysis capable of decomposing different temporal components of the dynamic carbon dioxide- Blood Oxygen-Level Dependent (CO 2-BOLD) relationship. EXPERIMENTAL DESIGN: Decomposition of the dynamic parameters included a redefinition of the voxel-wise CO 2 arrival time, and a separation from the vascular response to a stepwise increase in CO 2 (Delay to signal Plateau - DTP) and a decrease in CO 2 (Delay to signal Baseline -DTB)...
September 2017: Brain and Behavior
https://www.readbyqxmd.com/read/28923276/rapid-whole-brain-resting-state-fmri-at-3%C3%A2-t-efficiency-optimized-three-dimensional-epi-versus-repetition-time-matched-simultaneous-multi-slice-epi
#11
Rüdiger Stirnberg, Willem Huijbers, Daniel Brenner, Benedikt A Poser, Monique Breteler, Tony Stöcker
State-of-the-art simultaneous-multi-slice (SMS-)EPI and 3D-EPI share several properties that benefit functional MRI acquisition. Both sequences employ equivalent parallel imaging undersampling with controlled aliasing to achieve high temporal sampling rates. As a volumetric imaging sequence, 3D-EPI offers additional means of acceleration complementary to 2D-CAIPIRINHA sampling, such as fast water excitation and elliptical sampling. We performed an application-oriented comparison between a tailored, six-fold CAIPIRINHA-accelerated 3D-EPI protocol at 530 ms temporal and 2...
September 18, 2017: NeuroImage
https://www.readbyqxmd.com/read/28912749/functional-connectivity-of-the-corpus-callosum-in-epilepsy-patients-with-secondarily-generalized-seizures
#12
Syu-Jyun Peng, Yue-Loong Hsin
The corpus callosum (CC) plays an important role in generalization of seizure activity. We used resting-state function magnetic resonance imaging (rs-fMRI) to investigate the regional and interregional functional connectivity of CC in patients with magnetic resonance imaging (MRI)-negative and secondarily generalized seizures. We measured the multi-regional coherences of blood oxygen level-dependent (BOLD) signals via rs-fMRI, cortical thickness via high-resolution T1-weighted MRI, and white matter (WM) integrity via diffusion-tensor imaging in 16 epilepsy patients as well as in 16 age- and gender-matched healthy subjects...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28890416/bayesian-population-receptive-field-modelling
#13
REVIEW
Peter Zeidman, Edward Harry Silson, Dietrich Samuel Schwarzkopf, Chris Ian Baker, Will Penny
We introduce a probabilistic (Bayesian) framework and associated software toolbox for mapping population receptive fields (pRFs) based on fMRI data. This generic approach is intended to work with stimuli of any dimension and is demonstrated and validated in the context of 2D retinotopic mapping. The framework enables the experimenter to specify generative (encoding) models of fMRI timeseries, in which experimental stimuli enter a pRF model of neural activity, which in turns drives a nonlinear model of neurovascular coupling and Blood Oxygenation Level Dependent (BOLD) response...
September 8, 2017: NeuroImage
https://www.readbyqxmd.com/read/28885752/dual-echo-asl-contributes-to-decrypting-the-link-between-functional-connectivity-and-cerebral-blow-flow
#14
Silvia F Storti, Ilaria Boscolo Galazzo, Stefania Montemezzi, Gloria Menegaz, Francesca B Pizzini
Arterial spin labeling (ASL) MRI with a dual-echo readout module (DE-ASL) enables noninvasive simultaneous acquisition of cerebral blood flow (CBF)-weighted images and blood oxygenation level dependent (BOLD) contrast. Up to date, resting-state functional connectivity (FC) studies based on CBF fluctuations have been very limited, while the BOLD is still the method most frequently used. The purposes of this technical report were (i) to assess the potentiality of the DE-ASL sequence for the quantification of resting-state FC and brain organization, with respect to the conventional BOLD (cvBOLD) and (ii) to investigate the relationship between a series of complex network measures and the CBF information...
September 8, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28882632/spatial-specificity-of-the-functional-mri-blood-oxygenation-response-relative-to-neuronal-activity
#15
Denis Chaimow, Essa Yacoub, Kâmil Uğurbil, Amir Shmuel
Previous attempts at characterizing the spatial specificity of the blood oxygenation level dependent functional MRI (BOLD fMRI) response by estimating its point-spread function (PSF) have conventionally relied on retinotopic spatial representations of visual stimuli in area V1. Consequently, their estimates were confounded by the width and scatter of receptive fields of V1 neurons. Here, we circumvent these limits by instead using the inherent cortical spatial organization of ocular dominance columns (ODCs) to determine the PSF for both Gradient Echo (GE) and Spin Echo (SE) BOLD imaging at 7 Tesla...
September 5, 2017: NeuroImage
https://www.readbyqxmd.com/read/28868035/a-novel-stress-diathesis-model-to-predict-risk-of-post-operative-delirium-implications-for-intra-operative-management
#16
Renée El-Gabalawy, Ronak Patel, Kayla Kilborn, Caitlin Blaney, Christopher Hoban, Lawrence Ryner, Duane Funk, Regina Legaspi, Joseph A Fisher, James Duffin, David J Mikulis, W Alan C Mutch
Introduction: Risk assessment for post-operative delirium (POD) is poorly developed. Improved metrics could greatly facilitate peri-operative care as costs associated with POD are staggering. In this preliminary study, we develop a novel stress-diathesis model based on comprehensive pre-operative psychiatric and neuropsychological testing, a blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) carbon dioxide (CO2) stress test, and high fidelity measures of intra-operative parameters that may interact facilitating POD...
2017: Frontiers in Aging Neuroscience
https://www.readbyqxmd.com/read/28855117/how-motor-cognitive-and-musical-expertise-shapes-the-brain-focus-on-the-fmri-and-eeg-resting-state-functional-connectivity
#17
REVIEW
Pauline Cantou, Hervé Platel, Béatrice Desgranges, Mathilde Groussard
Brain activity and structure are shaped by life experiences. This plasticity has often been demonstrated with different types of expertise by using functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). Experts showed domain-specific functional neural changes during completion of a task when compared to non-experts. However, all of these results are task-dependent and even though they have proven useful for understanding neural interactions and their direct relation to individual skill, studying brain plasticity without any task might provide complementary information about functional cerebral reorganization due to expertise at the whole-brain level and might facilitate comparison across studies...
August 27, 2017: Journal of Chemical Neuroanatomy
https://www.readbyqxmd.com/read/28841675/neural-encoding-of-saltatory-pneumotactile-velocity-in-human-glabrous-hand
#18
Hyuntaek Oh, Rebecca Custead, Yingying Wang, Steven Barlow
Neurons in the somatosensory cortex are exquisitely sensitive to mechanical stimulation of the skin surface. The location, velocity, direction, and adaptation of tactile stimuli on the skin's surface are discriminable features of somatosensory processing, however the representation and processing of dynamic tactile arrays in the human somatosensory cortex are poorly understood. The principal aim of this study was to map the relation between dynamic saltatory pneumatic stimuli at discrete traverse velocities on the glabrous hand and the resultant pattern of evoked BOLD response in the human brain...
2017: PloS One
https://www.readbyqxmd.com/read/28837092/incorporating-oxygen-enhanced-mri-into-multi-parametric-assessment-of-human-prostate-cancer
#19
Heling Zhou, Rami R Hallac, Qing Yuan, Yao Ding, Zhongwei Zhang, Xian-Jin Xie, Franto Francis, Claus G Roehrborn, R Douglas Sims, Daniel N Costa, Ganesh V Raj, Ralph P Mason
Hypoxia is associated with prostate tumor aggressiveness, local recurrence, and biochemical failure. Magnetic resonance imaging (MRI) offers insight into tumor pathophysiology and recent reports have related transverse relaxation rate (R₂*) and longitudinal relaxation rate (R₁) measurements to tumor hypoxia. We have investigated the inclusion of oxygen-enhanced MRI for multi-parametric evaluation of tumor malignancy. Multi-parametric MRI sequences at 3 Tesla were evaluated in 10 patients to investigate hypoxia in prostate cancer prior to radical prostatectomy...
August 24, 2017: Diagnostics
https://www.readbyqxmd.com/read/28821668/sensory-biased-and-multiple-demand-processing-in-human-lateral-frontal-cortex
#20
Abigail L Noyce, Nishmar Cestero, Samantha W Michalka, Barbara G Shinn-Cunningham, David C Somers
The functionality of much of human lateral frontal cortex (LFC) has been characterized as "multiple demand" (MD) as these regions appear to support a broad range of cognitive tasks. In contrast to this domain-general account, recent evidence indicates that portions of LFC are consistently selective for sensory modality. Michalka et al. (2015) reported two bilateral regions that are biased for visual attention, superior precentral sulcus (sPCS) and inferior precentral sulcus (iPCS), interleaved with two bilateral regions that are biased for auditory attention, transverse gyrus intersecting precentral sulcus (tgPCS) and caudal inferior frontal sulcus (cIFS)...
September 6, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
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