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Neurovascular coupling

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https://www.readbyqxmd.com/read/28917813/structural-impacts-on-the-timing-and-amplitude-of-the-negative-bold-response
#1
David Provencher, Alexandre Bizeau, Guillaume Gilbert, Yves Bérubé-Lauzière, Kevin Whittingstall
The positive (PBR) and negative BOLD responses (NBR) arising in task-fMRI display varying magnitudes and dynamics across voxels. While the effects of structure, particularly of veins, on the PBR have been studied, little is known of NBR-structure relationships. Like the PBR, the NBR is often used as a surrogate marker of neuronal activation in both basic and clinical research and assessing its relationship with cortical structure may help interpret group differences. We therefore investigated how local structure affects BOLD amplitude and timing in PBR and NBR areas using multi-band fMRI during visual stimulation to obtain high temporal resolution (TR=0...
September 13, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28890416/bayesian-population-receptive-field-modelling
#2
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 7, 2017: NeuroImage
https://www.readbyqxmd.com/read/28875348/effects-of-dominant-and-non-dominant-passive-arm-manoeuvres-on-the-neurovascular-coupling-response
#3
Osian Llwyd, Ronney B Panerai, Thompson G Robinson
PURPOSE: Models designed to study neurovascular coupling (NVC) describe a possible cerebral hemisphere dominance dependent on task completed and preference in handedness. We investigated whether passive arm manoeuvre performed with dominant (Dom-Arm) or non-dominant arm (ND-Arm) stimulated haemodynamic differences in either contralateral (Cont-H) or ipsilateral (Ipsil-H) cerebral hemisphere. METHODS: Healthy individuals lying in supine position, had measurements of beat-to-beat blood pressure (BP, mmHg), electrocardiogram (HR, bpm), end-tidal CO2 (etCO2, mmHg), and bilateral insonation of the middle cerebral arteries (MCA, cm s(-1))...
September 5, 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28864913/pancreatic-neuro-insular-network-in-young-mice-revealed-by-3d-panoramic-histology
#4
Shiue-Cheng Tang, Chia-Ning Shen, Pei-Yu Lin, Shih-Jung Peng, Hung-Jen Chien, Ya-Hsien Chou, Chester E Chamberlain, Pankaj J Pasricha
AIMS/HYPOTHESIS: It has been proposed that the neuro-insular network enables rapid, synchronised insulin secretion. However, to date, acquiring the pancreatic tissue map to study the neural network remains a challenging task as there is a lack of feasible approaches for large-scale tissue analysis at the organ level. Here, we have developed 3-dimensional (3D) panoramic histology to characterise the pancreatic neuro-insular network in young mice. METHODS: Pancreases harvested from young wild-type B6 mice (3 and 8 weeks old) and db/db mice (3 weeks old; db/db vs db/+) were used to develop 3D panoramic histology...
September 1, 2017: Diabetologia
https://www.readbyqxmd.com/read/28860104/valsalva-induced-elevation-of-intracranial-pressure-selectively-decouples-deoxygenated-hemoglobin-concentration-from-neuronal-activation-and-functional-brain-imaging-capability
#5
Martin Knauth, Marcus Heldmann, Thomas F Münte, Georg Royl
During neuronal activation, neurovascular coupling leads to a local decrease of deoxygenated hemoglobin concentration (deoxy-Hb) and thus forms the basis of many functional brain mapping methods. In animals, an elevated intracranial pressure (ICP) can attenuate or even reverse this deoxy-Hb signaling. To study the effect of an elevated ICP on functional brain imaging in humans, we used different breathing tasks to modify ICP and analyzed the resulting effect on neurovascular coupling in the motor cortex. Functional near-infrared spectroscopy (fNIRS) was performed on 45 subjects during alternating conditions of finger tapping and resting state combined with four different breathing maneuvers (normal breathing (NB), breath holding without Valsalva maneuver (BH), Valsalva maneuver with 15 mm Hg forced expiratory pressure against resistance (V15) and Valsalva maneuver with 35 mm Hg forced expiratory pressure against resistance (V35)) in randomized order...
August 30, 2017: NeuroImage
https://www.readbyqxmd.com/read/28853030/hypertension-impairs-neurovascular-coupling-and-promotes-microvascular-injury-role-in-exacerbation-of-alzheimer-s-disease
#6
Anna Csiszar, Stefano Tarantini, Gábor A Fülöp, Tamas Kiss, M Noa Valcarcel-Ares, Veronica Galvan, Zoltan Ungvari, Andriy Yabluchanskiy
Hypertension in the elderly substantially increases both the risk of vascular cognitive impairment (VCI) and Alzheimer's disease (AD); however, the underlying mechanisms are not completely understood. This review discusses the effects of hypertension on structural and functional integrity of cerebral microcirculation, including hypertension-induced alterations in neurovascular coupling responses, cellular and molecular mechanisms involved in microvascular damage (capillary rarefaction, blood-brain barrier disruption), and the genesis of cerebral microhemorrhages and their potential role in exacerbation of cognitive decline associated with AD...
August 29, 2017: GeroScience
https://www.readbyqxmd.com/read/28842440/age-related-impairment-of-metabo-vascular-coupling-during-cortical-spreading-depolarization
#7
Stéphane Marinesco, Zoltán Ungvári, Veronica Galvan
Cortical spreading depolarizations (SDs) may lead to long-lasting alterations in cerebral blood flow (CBF), which contribute to neuronal dysfunction and hypoxic tissue injury. There is growing evidence to suggest that age-related structural and functional alterations of the neurovascular unit significantly increase both the incidence of SDs and aggravate their functional consequences. Recent studies suggest that metabolic signaling plays a major role in modulating cerebral blood flow responses evoked by SDs and provide critical evidence that aging considerably weakens metabovascular coupling with SD...
August 25, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28840162/simultaneous-functional-near-infrared-spectroscopy-and-electroencephalography-for-monitoring-of-human-brain-activity-and-oxygenation-a-review
#8
REVIEW
Antonio M Chiarelli, Filippo Zappasodi, Francesco Di Pompeo, Arcangelo Merla
Multimodal monitoring has become particularly common in the study of human brain function. In this context, combined, synchronous measurements of functional near-infrared spectroscopy (fNIRS) and electroencephalography (EEG) are getting increased interest. Because of the absence of electro-optical interference, it is quite simple to integrate these two noninvasive recording procedures of brain activity. fNIRS and EEG are both scalp-located procedures. fNIRS estimates brain hemodynamic fluctuations relying on spectroscopic measurements, whereas EEG captures the macroscopic temporal dynamics of brain electrical activity through passive voltages evaluations...
October 2017: Neurophotonics
https://www.readbyqxmd.com/read/28820467/aquaporin-4-functionality-and-virchow-robin-space-water-dynamics-physiological-model-for-neurovascular-coupling-and-glymphatic-flow
#9
REVIEW
Tsutomu Nakada, Ingrid L Kwee, Hironaka Igarashi, Yuji Suzuki
The unique properties of brain capillary endothelium, critical in maintaining the blood-brain barrier (BBB) and restricting water permeability across the BBB, have important consequences on fluid hydrodynamics inside the BBB hereto inadequately recognized. Recent studies indicate that the mechanisms underlying brain water dynamics are distinct from systemic tissue water dynamics. Hydrostatic pressure created by the systolic force of the heart, essential for interstitial circulation and lymphatic flow in systemic circulation, is effectively impeded from propagating into the interstitial fluid inside the BBB by the tightly sealed endothelium of brain capillaries...
August 18, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28813666/microrna-9-couples-brain-neurogenesis-and-angiogenesis
#10
Romain Madelaine, Steven A Sloan, Nina Huber, James H Notwell, Louis C Leung, Gemini Skariah, Caroline Halluin, Sergiu P Paşca, Gill Bejerano, Mark A Krasnow, Ben A Barres, Philippe Mourrain
In the developing brain, neurons expressing VEGF-A and blood vessels grow in close apposition, but many of the molecular pathways regulating neuronal VEGF-A and neurovascular system development remain to be deciphered. Here, we show that miR-9 links neurogenesis and angiogenesis through the formation of neurons expressing VEGF-A. We found that miR-9 directly targets the transcription factors TLX and ONECUTs to regulate VEGF-A expression. miR-9 inhibition leads to increased TLX and ONECUT expression, resulting in VEGF-A overexpression...
August 15, 2017: Cell Reports
https://www.readbyqxmd.com/read/28807409/a-decade-of-imaging-surgeons-brain-function-part-i-terminology-techniques-and-clinical-translation
#11
REVIEW
Hemel Narendra Modi, Harsimrat Singh, Guang-Zhong Yang, Ara Darzi, Daniel Richard Leff
BACKGROUND: Functional neuroimaging has the potential to deepen our understanding of technical and nontechnical skill acquisition in surgeons, particularly as established assessment tools leave unanswered questions about inter-operator differences in ability that seem independent of experience. METHODS: In this first of a 2-part article, we aim to utilize our experience in neuroimaging surgeons to orientate the nonspecialist reader to the principles of brain imaging...
August 11, 2017: Surgery
https://www.readbyqxmd.com/read/28807148/acetylcholine-induces-intracellular-ca-2-oscillations-and-nitric-oxide-release-in-mouse-brain-endothelial-cells
#12
Estella Zuccolo, Dmitry Lim, Dlzar Ali Kheder, Angelica Perna, Paolo Catarsi, Laura Botta, Vittorio Rosti, Laura Riboni, Giulio Sancini, Franco Tanzi, Egidio D'Angelo, Germano Guerra, Francesco Moccia
Basal forebrain neurons increase cortical blood flow by releasing acetylcholine (Ach), which stimulates endothelial cells (ECs) to produce the vasodilating gasotransmitter, nitric oxide (NO). Surprisingly, the mechanism whereby Ach induces NO synthesis in brain microvascular ECs is unknown. An increase in intracellular Ca(2+) concentration recruits a multitude of endothelial Ca(2+)-dependent pathways, such as Ca(2+)/calmodulin endothelial NO synthase (eNOS). The present investigation sought to investigate the role of intracellular Ca(2+) signaling in Ach-induced NO production in bEND5 cells, an established model of mouse brain microvascular ECs, by conventional imaging of cells loaded with the Ca(2+)-sensitive dye, Fura-2/AM, and the NO-sensitive fluorophore, DAF-DM diacetate...
September 2017: Cell Calcium
https://www.readbyqxmd.com/read/28804779/language-mapping-using-t2-prepared-bold-functional-mri-in-the-presence-of-large-susceptibility-artifacts-initial-results-in-patients-with-brain-tumor-and-epilepsy
#13
Jun Hua, Xinyuan Miao, Shruti Agarwal, Chetan Bettegowda, Alfredo Quiñones-Hinojosa, John Laterra, Peter C M Van Zijl, James J Pekar, Jay J Pillai
At present, presurgical functional mapping is the most prevalent clinical application of functional magnetic resonance imaging (fMRI). Signal dropouts and distortions caused by susceptibility effects in the current standard echo planar imaging (EPI)-based fMRI images are well-known problems and pose a major hurdle for the application of fMRI in several brain regions, many of which are related to language mapping in presurgical planning. Such artifacts are particularly problematic in patients with previous surgical resection cavities, craniotomy hardware, hemorrhage, and vascular malformation...
June 2017: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28792278/astrocytic-endfoot-ca-2-correlates-with-parenchymal-vessel-responses-during-4-ap-induced-epilepsy-an-in%C3%A2-vivo-two-photon-lifetime-microscopy-study
#14
Cong Zhang, Maryam Tabatabaei, Samuel Bélanger, Hélène Girouard, Mohammad Moeini, Xuecong Lu, Frédéric Lesage
Neurovascular coupling (NVC) underlying the local increase in blood flow during neural activity forms the basis of functional brain imaging and is altered in epilepsy. Because astrocytic calcium (Ca(2+)) signaling is involved in NVC, this study investigates the role of this pathway in epilepsy. Here, we exploit 4-AP induced epileptic events to show that absolute Ca(2+) concentration in cortical astrocyte endfeet in vivo correlates with the diameter of precapillary arterioles during neural activity. We simultaneously monitored free Ca(2+) concentration in astrocytic endfeet with the Ca(2+)-sensitive indicator OGB-1 and diameter of adjacent arterioles in the somatosensory cortex of adult mice by two-photon fluorescence lifetime measurements following 4-AP injection...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28782872/the-role-of-vascular-resistance-in-bold-responses-to-progressive-hypercapnia
#15
James Duffin, Olivia Sobczyk, Adrian Crawley, Julien Poublanc, Lashmi Venkatraghavan, Kevin Sam, Alan Mutch, David Mikulis, Joseph Fisher
The ability of the cerebral vasculature to regulate vascular diameter, hence resistance and cerebral blood flow (CBF), in response to metabolic demands (neurovascular coupling), and perfusion pressure changes (autoregulation) may be assessed by measuring the CBF response to carbon dioxide (CO2 ). In healthy individuals, the CBF response to a ramp CO2 stimulus from hypocapnia to hypercapnia is assumed sigmoidal or linear. However, other response patterns commonly occur, especially in individuals with cerebrovascular disease, and these remain unexplained...
August 7, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28776759/melatonin-ameliorates-hypoglycemic-stress-induced-brain-endothelial-tight-junction-injury-by-inhibiting-protein-nitration-of-tp53-induced-glycolysis-and-apoptosis-regulator
#16
Cheng-Kun Wang, Muhammad Masood Ahmed, Quan Jiang, Nan-Nan Lu, Chao Tan, Yin-Ping Gao, Qaisar Mahmood, Dan-Yang Chen, Kohji Fukunaga, Mei Li, Zhong Chen, Christopher S Wilcox, Ying-Mei Lu, Zheng-Hong Qin, Feng Han
Severe hypoglycemia has a detrimental impact on the cerebrovasculature, but the molecular events that lead to the disruption of the integrity of the tight junctions remain unclear. Here, we report that the microvessel integrity was dramatically compromised (59.41% of wild-type mice) in TP53-induced glycolysis and apoptosis regulator (TIGAR) transgenic mice stressed by hypoglycemia. Melatonin, a potent antioxidant, protects against hypoglycemic stress-induced brain endothelial tight junction injury in the dosage of 400 nmol/L in vitro...
August 4, 2017: Journal of Pineal Research
https://www.readbyqxmd.com/read/28769866/eye-control-deficits-coupled-to-hand-control-deficits-eye-hand-incoordination-in-chronic-cerebral-injury
#17
John-Ross Rizzo, James K Fung, Maryam Hosseini, Azadeh Shafieesabet, Edmond Ahdoot, Rosa M Pasculli, Janet C Rucker, Preeti Raghavan, Michael S Landy, Todd E Hudson
It is widely accepted that cerebral pathology can impair ocular motor and manual motor control. This is true in indolent and chronic processes, such as neurodegeneration and in acute processes such as stroke or those secondary to neurotrauma. More recently, it has been suggested that disruptions in these control systems are useful markers for prognostication and longitudinal monitoring. The utility of examining the relationship or the coupling between these systems has yet to be determined. We measured eye and hand-movement control in chronic, middle cerebral artery stroke, relative to healthy controls, in saccade-to-reach paradigms to assess eye-hand coordination...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28769767/pannexins-are-potential-new-players-in-the-regulation-of-cerebral-homeostasis-during-sleep-wake-cycle
#18
Valery I Shestopalov, Yuri Panchin, Olga S Tarasova, Dina Gaynullina, Vladimir M Kovalzon
During brain homeostasis, both neurons and astroglia release ATP that is rapidly converted to adenosine in the extracellular space. Pannexin-1 (Panx1) hemichannels represent a major conduit of non-vesicular ATP release from brain cells. Previous studies have shown that Panx1(-/-) mice possess severe disruption of the sleep-wake cycle. Here, we review experimental data supporting the involvement of pannexins (Panx) in the coordination of fundamental sleep-associated brain processes, such as neuronal activity and regulation of cerebrovascular tone...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28743861/multimodal-fingerprints-of-resting-state-networks-as-assessed-by-simultaneous-trimodal-mr-pet-eeg-imaging
#19
N J Shah, J Arrubla, R Rajkumar, E Farrher, J Mauler, E Rota Kops, L Tellmann, J Scheins, F Boers, J Dammers, P Sripad, C Lerche, K J Langen, H Herzog, I Neuner
Simultaneous MR-PET-EEG (magnetic resonance imaging - positron emission tomography - electroencephalography), a new tool for the investigation of neuronal networks in the human brain, is presented here for the first time. It enables the assessment of molecular metabolic information with high spatial and temporal resolution in a given brain simultaneously. Here, we characterize the brain's default mode network (DMN) in healthy male subjects using multimodal fingerprinting by quantifying energy metabolism via 2- [(18)F]fluoro-2-desoxy-D-glucose PET (FDG-PET), the inhibition - excitation balance of neuronal activation via magnetic resonance spectroscopy (MRS), its functional connectivity via fMRI and its electrophysiological signature via EEG...
July 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28736653/hemispheric-differences-in-electrical-and-hemodynamic-responses-during-hemifield-visual-stimulation-with-graded-contrasts
#20
Juanning Si, Xin Zhang, Yujin Zhang, Tianzi Jiang
A multimodal neuroimaging technique based on electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) was used with horizontal hemifield visual stimuli with graded contrasts to investigate the retinotopic mapping more fully as well as to explore hemispheric differences in neuronal activity, the hemodynamic response, and the neurovascular coupling relationship in the visual cortex. The fNIRS results showed the expected activation over the contralateral hemisphere for both the left and right hemifield visual stimulations...
April 1, 2017: Biomedical Optics Express
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