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Neurovascular coupling

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https://www.readbyqxmd.com/read/28807409/a-decade-of-imaging-surgeons-brain-function-part-i-terminology-techniques-and-clinical-translation
#1
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
#2
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
#3
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
#4
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
#5
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-tigar
#6
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 remains 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 nM 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
#7
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
#8
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
#9
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
#10
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
https://www.readbyqxmd.com/read/28736310/non-bold-contrast-for-laminar-fmri-in-humans-cbf-cbv-and-cmro2
#11
REVIEW
Laurentius Huber, Kâmil Uludağ, Harald E Möller
Functional magnetic resonance imaging (fMRI) using the blood oxygenation level-dependent (BOLD) contrast indirectly probes neuronal activity changes via evoked cerebral blood flow (CBF), cerebral blood volume (CBV) and cerebral metabolic rate of oxygen (CMRO2) changes. The gradient-echo BOLD signal is mostly sensitive to ascending veins in the tissue and to pial veins. Thereby, the achievable spatial specificity to neuronal activation is limited. Furthermore, the non-linear interaction of CBF, CBV and CMRO2 can hamper quantitative interpretations of the BOLD signal across cortical depths with different baseline physiology...
July 20, 2017: NeuroImage
https://www.readbyqxmd.com/read/28736308/laminar-fmri-what-can-the-time-domain-tell-us
#12
REVIEW
Natalia Petridou, Jeroen C W Siero
The rapid developments in functional MRI (fMRI) acquisition methods and hardware technologies in recent years, particularly at high field (≥7 T), have enabled unparalleled visualization of functional detail at a laminar or columnar level, bringing fMRI close to the intrinsic resolution of brain function. These advances highlight the potential of high resolution fMRI to be a valuable tool to study the fundamental processing performed in cortical micro-circuits, and their interactions such as feedforward and feedback processes...
July 20, 2017: NeuroImage
https://www.readbyqxmd.com/read/28729926/coherence-of-bold-signal-and-electrical-activity-in-the-human-brain-during-deep-sevoflurane-anesthesia
#13
Daniel Golkowski, Andreas Ranft, Tobias Kiel, Valentin Riedl, Philipp Kohl, Guido Rohrer, Joachim Pientka, Sebastian Berger, Christine Preibisch, Claus Zimmer, George A Mashour, Gerhard Schneider, Eberhard F Kochs, Rüdiger Ilg, Denis Jordan
INTRODUCTION: Changes in neural activity induce changes in functional magnetic resonance (fMRI) blood oxygenation level dependent (BOLD) signal. Commonly, increases in BOLD signal are ascribed to cellular excitation. OBJECTIVE: The relationship between electrical activity and BOLD signal in the human brain was probed on the basis of burst suppression EEG. This condition includes two distinct states of high and low electrical activity. METHODS: Resting-state simultaneous EEG and BOLD measurements were acquired during deep sevoflurane anesthesia with burst suppression EEG in nineteen healthy volunteers...
July 2017: Brain and Behavior
https://www.readbyqxmd.com/read/28729163/computational-analysis-of-interactions-of-oxidative-stress-and-tetrahydrobiopterin-reveals-instability-in-enos-coupling
#14
Sheetal Joshi, Saptarshi Kar, Mahendra Kavdia
In cardiovascular and neurovascular diseases, an increase in oxidative stress and endothelial dysfunction has been reported. There is a reduction in tetrahydrobiopterin (BH4), which is a cofactor for the endothelial nitric oxide synthase (eNOS), resulting in eNOS uncoupling. Studies of the enhancement of BH4 availability have reported mixed results for improvement in endothelial dysfunction. Our understanding of the complex interactions of eNOS uncoupling, oxidative stress and BH4 availability is not complete and a quantitative understanding of these interactions is required...
July 18, 2017: Microvascular Research
https://www.readbyqxmd.com/read/28714074/altered-metabolomic-genomic-signature-a-potential-noninvasive-biomarker-of-epilepsy
#15
Helen C Wu, Fabien Dachet, Farhad Ghoddoussi, Shruti Bagla, Darren Fuerst, Jeffrey A Stanley, Matthew P Galloway, Jeffrey A Loeb
OBJECTIVE: This study aimed to identify noninvasive biomarkers of human epilepsy that can reliably detect and localize epileptic brain regions. Having noninvasive biomarkers would greatly enhance patient diagnosis, patient monitoring, and novel therapy development. At the present time, only surgically invasive, direct brain recordings are capable of detecting these regions with precision, which severely limits the pace and scope of both clinical management and research progress in epilepsy...
July 17, 2017: Epilepsia
https://www.readbyqxmd.com/read/28712093/neurobiological-effect-of-selective-brain-cooling-after-concussive-injury
#16
Alexa Walter, Katie Finelli, Xiaoxiao Bai, Brian Johnson, Thomas Neuberger, Peter Seidenberg, Timothy Bream, Mark Hallett, Semyon Slobounov
The search for effective treatment facilitating recovery from concussive injury, as well as reducing risk for recurrent concussion is an ongoing challenge. This study aimed to determine: a) feasibility of selective brain cooling to facilitate clinical symptoms resolution, and b) biological functions of the brain within athletes in acute phase of sports-related concussion. Selective brain cooling for 30 minutes using WElkins sideline cooling system was administered to student-athletes suffering concussive injury (n=12; tested within 5±3 days) and those without history of concussion (n=12)...
July 15, 2017: Brain Imaging and Behavior
https://www.readbyqxmd.com/read/28687518/neural-inhibition-can-explain-negative-bold-responses-a-mechanistic-modelling-and-fmri-study
#17
S Sten, K Lundengård, S T Witt, G Cedersund, F Elinder, M Engström
Functional magnetic resonance imaging (fMRI) of hemodynamic changes captured in the blood oxygen level-dependent (BOLD) response contains information of brain activity. The BOLD response is the result of a complex neurovascular coupling and comes in at least two fundamentally different forms: a positive and a negative deflection. Because of the complexity of the signaling, mathematical modelling can provide vital help in the data analysis. For the positive BOLD response, there are plenty of mathematical models, both physiological and phenomenological...
July 4, 2017: NeuroImage
https://www.readbyqxmd.com/read/28649158/implementation-of-material-decomposition-using-an-emccd-and-cmos-based-micro-ct-system
#18
Alexander R Podgorsak, Sv Setlur Nagesh, Daniel R Bednarek, Stephen Rudin, Ciprian N Ionita
This project assessed the effectiveness of using two different detectors to obtain dual-energy (DE) micro-CT data for the carrying out of material decomposition. A micro-CT coupled to either a complementary metal-oxide semiconductor (CMOS) or an electron multiplying CCD (EMCCD) detector was used to acquire image data of a 3D-printed phantom with channels filled with different materials. At any instance, materials such as iohexol contrast agent, water, and platinum were selected to make up the scanned object...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28646017/ror%C3%AE-modulates-semaphorin-3e-transcription-and-neurovascular-interaction-in-pathological-retinal-angiogenesis
#19
Ye Sun, Chi-Hsiu Liu, Zhongxiao Wang, Steven S Meng, Samuel B Burnim, John Paul SanGiovanni, Theodore M Kamenecka, Laura A Solt, Jing Chen
Pathological proliferation of retinal blood vessels commonly causes vision impairment in proliferative retinopathies, including retinopathy of prematurity. Dysregulated crosstalk between the vasculature and retinal neurons is increasingly recognized as a major factor contributing to the pathogenesis of vascular diseases. Class 3 semaphorins (SEMA3s), a group of neuron-secreted axonal and vascular guidance factors, suppress pathological vascular growth in retinopathy. However, the upstream transcriptional regulators that mediate the function of SEMA3s in vascular growth are poorly understood...
June 23, 2017: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
https://www.readbyqxmd.com/read/28643877/cerebral-haemodynamic-response-to-somatosensory-stimulation-in-neonatal-lambs
#20
Shinji Nakamura, David W Walker, Flora Y Wong
KEY POINTS: Cerebral haemodynamic response to neural stimulation has been extensively studied in adults, but little is known about cerebral haemodynamic response in the fetal and neonatal brain. The present study describes the cerebral haemodynamic response measured by near infrared spectroscopy to somatosensory stimulation in newborn lambs, in comparison to recent findings in fetal sheep. The cerebral haemodynamic responses in the newborn lamb brain can involve an increase in oxyhaemoglobin (oxyHb), or a decrease of oxyHb suggestive of reduced perfusion and oxygenation...
June 23, 2017: Journal of Physiology
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