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https://www.readbyqxmd.com/read/28534652/a-review-of-the-evidence-of-zolpidem-efficacy-in-neurological-disability-after-brain-damage-due-to-stroke-trauma-and-hypoxia-a-justification-of-further-clinical-trials
#1
J A Sutton, R P Clauss
During 15 years, 23 clinical reports and 6 studies have demonstrated associations between sub-sedative doses of zolpidem and recoveries from brain damage due to strokes, trauma and hypoxia. Clinical findings include unexpected awakenings from vegetative states and regressions of stroke symptoms after dosing that disappear during elimination and reappear on repeat dosing. Initially single-photon emission computed tomography scans showed improved perfusion within, around and distant from infarctions. Then positron emission tomography scans and electroencephalography detected renewed metabolic and neuronal activity...
May 23, 2017: Brain Injury: [BI]
https://www.readbyqxmd.com/read/28528845/comparison-of-3-and-7-t-asl-techniques-for-concurrent-functional-perfusion-and-bold-studies
#2
Dimo Ivanov, Anna Gardumi, Roy Am Haast, Josef Pfeuffer, Benedikt A Poser, Kâmil Uludağ
Arterial spin labeling (ASL) is the primary non-invasive MRI approach to measure baseline cerebral blood flow (CBF) in healthy subjects and patients. ASL also allows concurrent functional BOLD signal and CBF measurements, but the latter typically suffers from low contrast-to-noise (CNR) ratio. Ultra-high-field imaging significantly boosts BOLD signal CNR. However, it is contested whether also CBF CNR benefits from increasing magnetic field strength, especially given that technical challenges related to field inhomogeneities and power deposition constraints exist...
May 18, 2017: NeuroImage
https://www.readbyqxmd.com/read/28506874/impact-of-acquisition-and-analysis-strategies-on-cortical-depth-dependent-fmri
#3
Sriranga Kashyap, Dimo Ivanov, Martin Havlicek, Benedikt A Poser, Kâmil Uludağ
Functional MRI at ultra-high magnetic fields (≥ 7T) provides the opportunity to probe columnar and laminar processing in the human brain in vivo at submillimeter spatial scales. However, fMRI data only indirectly reflects the neuronal laminar profile, due to a bias to ascending and pial veins inherent in gradient- and spin-echo BOLD fMRI. In addition, accurate delineation of the cortical depths is difficult, due to the relatively large voxel sizes and lack of sufficient tissue contrast in the functional images...
May 12, 2017: NeuroImage
https://www.readbyqxmd.com/read/28504360/oxygen-extraction-fraction-mapping-at-3-tesla-using-an-artificial-neural-network-a-feasibility-study
#4
Sebastian Domsch, Bettina Mürle, Sebastian Weingärtner, Jascha Zapp, Frederik Wenz, Lothar R Schad
PURPOSE: The oxygen extraction fraction (OEF) is an important biomarker for tissue-viability. MRI enables noninvasive estimation of the OEF based on the blood-oxygenation-level-dependent (BOLD) effect. Quantitative OEF-mapping is commonly applied using least-squares regression (LSR) to an analytical tissue model. However, the LSR method has not yet become clinically established due to the necessity for long acquisition times. Artificial neural networks (ANNs) recently have received increasing interest for robust curve-fitting and might pose an alternative to the conventional LSR method for reduced acquisition times...
May 14, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28502844/a-novel-approach-to-map-induced-activation-of-neuronal-networks-using-chemogenetics-and-functional-neuroimaging-in-rats-a-proof-of-concept-study-on-the-mesocorticolimbic-system
#5
Theresia J M Roelofs, Jeroen P H Verharen, Geralda A F van Tilborg, Linde Boekhoudt, Annette van der Toorn, Johannes W de Jong, Mieneke C M Luijendijk, Willem M Otte, Roger A H Adan, Rick M Dijkhuizen
Linking neural circuit activation at whole-brain level to neuronal activity at cellular level remains one of the major challenges in neuroscience research. We set up a novel functional neuroimaging approach to map global effects of locally induced activation of specific midbrain projection neurons using chemogenetics (Designer Receptors Exclusively Activated by Designer Drugs (DREADD)-technology) combined with pharmacological magnetic resonance imaging (phMRI) in the rat mesocorticolimbic system. Chemogenetic activation of DREADD-targeted mesolimbic or mesocortical pathways, i...
May 11, 2017: NeuroImage
https://www.readbyqxmd.com/read/28462586/infraslow-eeg-and-dynamic-resting-state-network-activity
#6
Joshua K Grooms, Garth John Thompson, Wen-Ju Pan, Jacob Billings, Eric H Schumacher, Charles M Epstein, Shella Dawn Keilholz
A number of studies have linked the BOLD signal to EEG signals in traditional frequency bands (δ, θ, α, β, and γ), but the relationship between BOLD and its direct frequency correlates in the infraslow band (<1 Hz) has been little studied. Previously, work in rodents showed that infraslow local field potentials play a role in functional connectivity, particularly in the dynamic organization of large-scale networks. To examine the relationship between infraslow activity and network dynamics in humans, direct current (DC) EEG and resting state MRI data were acquired simultaneously...
May 2, 2017: Brain Connectivity
https://www.readbyqxmd.com/read/28460835/a-chronic-in-situ-coil-system-adapted-for-intracerebral-stimulation-during-mri-in-rats
#7
Dan Madularu, Chathura Kumaragamage, Axel P Mathieu, Praveen Kulkarni, M Natasha Rajah, Alain P Gratton, Jamie Near
BACKGROUND: We describe the fabrication and performance of a chronic in situ coil system designed to allow focal brain stimulation in rats while acquiring functional MRI data. NEW METHOD: An implantable receive-only surface radiofrequency coil (iCoil) was designed to be fitted subcutaneously, directly onto to the rat skull surface during the intracerebral cannulation procedure. The coil is fixed in place using acrylic dental cement anchored to four screws threaded into the skull...
June 1, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/28456172/structural-connectome-topology-relates-to-regional-bold-signal-dynamics-in-the-mouse-brain
#8
Sarab S Sethi, Valerio Zerbi, Nicole Wenderoth, Alex Fornito, Ben D Fulcher
Brain dynamics are thought to unfold on a network determined by the pattern of axonal connections linking pairs of neuronal elements; the so-called connectome. Prior work has indicated that structural brain connectivity constrains pairwise correlations of brain dynamics ("functional connectivity"), but it is not known whether inter-regional axonal connectivity is related to the intrinsic dynamics of individual brain areas. Here we investigate this relationship using a weighted, directed mesoscale mouse connectome from the Allen Mouse Brain Connectivity Atlas and resting state functional MRI (rs-fMRI) time-series data measured in 184 brain regions in eighteen anesthetized mice...
April 2017: Chaos
https://www.readbyqxmd.com/read/28449077/executive-network-activation-is-linked-to-walking-speed-in-older-adults-functional-mri-and-tcd-ultrasound-evidence-from-the-mobilize-boston-study
#9
Azizah J Jor'dan, Victoria N Poole, Ikechukwu Iloputaife, William Milberg, Brad Manor, Michael Esterman, Lewis A Lipsitz
Background: Changes in cerebral blood flow velocity (CBF) in response to a cognitive task (task-related ΔCBF) have been shown by Transcranial Doppler ultrasonography (TCD) to be reduced in slow walkers. However, it is unknown whether reduced task-related ΔCBF is associated with reduced neural activity in specific brain regions, as measured by blood-oxygen-level dependent (BOLD) functional magnetic resonance imaging (fMRI). Methods: We assessed the regional changes in neural activity associated with reduced middle cerebral artery (MCA) task-related ΔCBF to an executive task and slow walking speed in 67 community-dwelling older adults from the MOBILIZE Boston Study...
April 26, 2017: Journals of Gerontology. Series A, Biological Sciences and Medical Sciences
https://www.readbyqxmd.com/read/28444823/dissociable-corticostriatal-circuits-underlie-goal-directed-versus-cue-elicited-habitual-food-seeking-after-satiation-evidence-from-a-multimodal-mri-study
#10
Henk van Steenbergen, Poppy Watson, Reinout W Wiers, Bernhard Hommel, Sanne de Wit
The present multimodal MRI study advances our understanding of the corticostriatal circuits underlying goal-directed versus cue-driven, habitual food seeking. To this end, we employed a computerized Pavlovian-instrumental transfer (PIT) paradigm. During the test phase, participants were free to perform learnt instrumental responses (left and right key presses) for popcorn and Smarties outcomes. Importantly, prior to this test half of the participants had been sated on popcorn and the other half on Smarties - resulting in a reduced desirability of those outcomes...
April 26, 2017: European Journal of Neuroscience
https://www.readbyqxmd.com/read/28443736/brain-resting-state-functional-connectivity-is-preserved-under-sevoflurane-anesthesia-in-patients-with-pervasive-developmental-disorders-a-pilot-study
#11
Lakshmikumar Venkatraghavan, Suparna Bharadwaj, Vincent Wourms, Audrey Tan, Michael T Jurkiewicz, David J Mikulis, Adrian P Crawley
Functional connectivity studies play a huge role in understanding the relationship between the network connections and the behavioral phenotype of patients with pervasive developmental disorders (PDD). Some patients with PDD may not be able to tolerate the imaging procedure while they are awake, and, hence, they often need general anesthesia. General anesthesia is a confounding factor in functional imaging studies due to its effect on the functional connectivity. The objective of this study is to look at the resting-state functional connectivity (RS-FC) under sevoflurane anesthesia in patients with PDDs...
May 2017: Brain Connectivity
https://www.readbyqxmd.com/read/28441420/mapping-of-the-brain-hemodynamic-responses-to-sensorimotor-stimulation-in-a-rodent-model-a-bold-fmri-study
#12
Salem Boussida, Amidou S Traoré, Franck Durif
Blood Oxygenation Level Dependent functional MRI (BOLD fMRI) during electrical paw stimulation has been widely used in studies aimed at the understanding of the somatosensory network in rats. However, despite the well-established anatomical connections between cortical and subcortical structures of the sensorimotor system, most of these functional studies have been concentrated on the cortical effects of sensory electrical stimulation. BOLD fMRI study of the integration of a sensorimotor input across the sensorimotor network requires an appropriate methodology to elicit functional activation in cortical and subcortical areas owing to the regional differences in both neuronal and vascular architectures between these brain regions...
2017: PloS One
https://www.readbyqxmd.com/read/28437782/detection-of-renal-hypoxia-in-lupus-nephritis-using-blood-oxygen-level-dependent-mr-imaging-a-multiple-correspondence-analysis
#13
Huilan Shi, Tiekun Yan, Dong Li, Junya Jia, Wenya Shang, Li Wei, Zhenfeng Zheng
BACKGROUND/AIMS: Nephrologists have pursued ideal, dynamic and noninvasive methods for assessing renal function and disease progression. Blood oxygen level dependent (BOLD) imaging is a useful technique for assessing renal disease. This current study was performed to explore the correlation between the hypoxia iconographical index and renal pathological features in lupus nephritis. METHODS: Adult patients with lupus nephritis (LN) and healthy volunteers were recruited for this study...
2017: Kidney & Blood Pressure Research
https://www.readbyqxmd.com/read/28424572/functional-sensitivity-of-2d-simultaneous-multi-slice-echo-planar-imaging-effects-of-acceleration-on-g-factor-and-physiological-noise
#14
Nick Todd, Oliver Josephs, Peter Zeidman, Guillaume Flandin, Steen Moeller, Nikolaus Weiskopf
Accelerated data acquisition with simultaneous multi-slice (SMS) imaging for functional MRI studies leads to interacting and opposing effects that influence the sensitivity to blood oxygen level-dependent (BOLD) signal changes. Image signal to noise ratio (SNR) is decreased with higher SMS acceleration factors and shorter repetition times (TR) due to g-factor noise penalties and saturation of longitudinal magnetization. However, the lower image SNR is counteracted by greater statistical power from more samples per unit time and a higher temporal Nyquist frequency that allows for better removal of spurious non-BOLD high frequency signal content...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28421854/reduction-of-bold-interference-in-pseudo-continuous-arterial-spin-labeling-towards-quantitative-fmri
#15
Geoffrey Warnock, Pinar S Özbay, Felix P Kuhn, Daniel Nanz, Alfred Buck, Andreas Boss, Cristina Rossi
Fluctuations in blood-oxygenation level dependent (BOLD) signal and perfusion affect the quantification of changes in cerebral blood flow (CBF), coupled to neuronal activity, in arterial spin labeling (ASL). Subtraction methods for control and labeled MR images (i.e. pair-wise, surround subtraction, and subtraction of sinc-interpolated images), postulated to mitigate this interference in pseudo-continuous ASL (pCASL), were evaluated by comparison with quantitative (15)O-water PET. At rest, a good agreement in the CBF values was found between PET and MRI for each of the subtraction methods...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28415581/tumor-physiological-changes-during-hypofractionated-stereotactic-body-radiation-therapy-assessed-using-multi-parametric-magnetic-resonance-imaging
#16
Heling Zhou, Zhang Zhang, Rebecca Denney, Jessica S Williams, Jeni Gerberich, Strahinja Stojadinovic, Debabrata Saha, John M Shelton, Ralph P Mason
Radiation therapy is a primary treatment for non-resectable lung cancer and hypoxia is thought to influence tumor response. Hypoxia is expected to be particularly relevant to the evolving new radiation treatment scheme of hypofractionated stereotactic body radiation therapy (SBRT). As such, we sought to develop non-invasive tools to assess tumor pathophysiology and response to irradiation. We applied blood oxygen level dependent (BOLD) and tissue oxygen level dependent (TOLD) MRI, together with dynamic contrast enhanced (DCE) MRI to explore the longitudinal effects of SBRT on tumor oxygenation and vascular perfusion using A549 human lung cancer xenografts in a subcutaneous rat model...
March 21, 2017: Oncotarget
https://www.readbyqxmd.com/read/28406906/water-diffusion-closely-reveals-neural-activity-status-in-rat-brain-loci-affected-by-anesthesia
#17
Yoshifumi Abe, Tomokazu Tsurugizawa, Denis Le Bihan
Diffusion functional MRI (DfMRI) reveals neuronal activation even when neurovascular coupling is abolished, contrary to blood oxygenation level-dependent (BOLD) functional MRI (fMRI). Here, we show that the water apparent diffusion coefficient (ADC) derived from DfMRI increased in specific rat brain regions under anesthetic conditions, reflecting the decreased neuronal activity observed with local field potentials (LFPs), especially in regions involved in wakefulness. In contrast, BOLD signals showed nonspecific changes, reflecting systemic effects of the anesthesia on overall brain hemodynamics status...
April 2017: PLoS Biology
https://www.readbyqxmd.com/read/28396293/the-impact-of-ultra-high-field-mri-on-cognitive-and-computational-neuroimaging
#18
Federico De Martino, Essa Yacoub, Valentin Kemper, Michelle Moerel, Kamil Uludag, Peter De Weerd, Kamil Ugurbil, Rainer Goebel, Elia Formisano
The ability to measure functional brain responses non-invasively with ultra high field MRI (7 T and above) represents a unique opportunity in advancing our understanding of the human brain. Compared to lower fields (3 T and below), ultra high field MRI has an increased sensitivity, which can be used to acquire functional images with greater spatial resolution, and greater specificity of the blood oxygen level dependent (BOLD) signal to the underlying neuronal responses. Together, increased resolution and specificity enable investigating brain functions at a submillimeter scale, which so far could only be done with invasive techniques...
April 7, 2017: NeuroImage
https://www.readbyqxmd.com/read/28374506/g-csf-and-cognitive-dysfunction-in-elderly-diabetic-mice-with-cerebral-small-vessel-disease-preventive-intervention-effects-and-underlying-mechanisms
#19
Zhu-Fei Guan, Ying-Hong Tao, Xiao-Ming Zhang, Qi-Lin Guo, Ying-Chao Liu, Yu Zhang, Yan-Mei Wang, Gang Ji, Guo-Feng Wu, Na-Na Wang, Hao Yang, Zhong-Yu Yu, Jing-Chun Guo, Hou-Guang Zhou
AIMS: Although cognitive dysfunction is a common neurological complication in elderly patients with diabetes, the mechanisms underlying this relationship remain unclear, and effective preventive interventions have yet to be developed. Thus, this study investigated the preventive effects and mechanisms of action associated with granulocyte colony-stimulating factor (G-CSF) on cognitive dysfunction in elderly diabetic mice with cerebral small vessel disease. METHODS: This study included 40 male db/db diabetic and wild-type (WT) mice that were categorized into the following four groups at the age of 3 weeks: db/db group (DG), db/db+G-CSF group (DGG), WT group (WG), and WT+G-CSF group (WGG)...
April 4, 2017: CNS Neuroscience & Therapeutics
https://www.readbyqxmd.com/read/28374010/following-eye-gaze-activates-a-patch-in-the-posterior-temporal-cortex-that-is-not-part-of-the-human-face-patch-system
#20
Kira Marquardt, Hamidreza Ramezanpour, Peter W Dicke, Peter Thier
Humans follow another person's eye gaze to objects of interest to the other, thereby establishing joint attention, a first step toward developing a theory of the other's mind. Previous functional MRI studies agree that a "gaze-following patch" (GFP) of cortex close to the posterior superior temporal sulcus (STS) is specifically implicated in eye gaze-following. The location of the GFP is in the vicinity of the posterior members of the core face-processing system that consists of distinct patches in ventral visual cortex, the STS, and frontal cortex, also involved in processing information on the eyes...
March 2017: ENeuro
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