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BOLD fmri and anesthesia

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https://www.readbyqxmd.com/read/30251760/functional-connectivity-with-cortical-depth-assessed-by-resting-state-fmri-of-subregions-of-s1-in-squirrel-monkeys
#1
Arabinda Mishra, Shantanu Majumdar, Feng Wang, George H Wilson, John C Gore, Li Min Chen
Whereas resting state blood oxygenation-level dependent (BOLD) functional MRI has been widely used to assess functional connectivity between cortical regions, the laminar specificity of such measures is poorly understood. This study aims to determine: (a) whether the resting state functional connectivity (rsFC) between two functionally related cortical regions varies with cortical depth, (b) the relationship between layer-resolved tactile stimulus-evoked activation pattern and interlayer rsFC pattern between two functionally distinct but related somatosensory areas 3b and 1, and (c) the effects of spatial resolution on rsFC measures...
September 25, 2018: Human Brain Mapping
https://www.readbyqxmd.com/read/30140206/fmri-based-brain-responses-to-quinine-and-sucrose-gustatory-stimulation-for-nutrition-research-in-the-minipig-model-a-proof-of-concept-study
#2
Nicolas Coquery, Paul Meurice, Régis Janvier, Eric Bobillier, Stéphane Quellec, Minghai Fu, Eugeni Roura, Hervé Saint-Jalmes, David Val-Laillet
The minipig model is of high interest for brain research in nutrition and associated pathologies considering the similarities to human nutritional physiology, brain structures, and functions. In the context of a gustatory stimulation paradigm, fMRI can provide crucial information about the sensory, cognitive, and hedonic integration of exteroceptive stimuli in healthy and pathological nutritional conditions. Our aims were (i) to validate the experimental setup, i.e., fMRI acquisition and SPM-based statistical analysis, with a visual stimulation; (ii) to implement the fMRI procedure in order to map the brain responses to different gustatory stimulations, i...
2018: Frontiers in Behavioral Neuroscience
https://www.readbyqxmd.com/read/30090873/high-energy-brain-dynamics-during-anesthesia-induced-unconsciousness
#3
James R Riehl, Ben J Palanca, ShiNung Ching
Characterizing anesthesia-induced alterations to brain network dynamics provides a powerful framework to understand the neural mechanisms of unconsciousness. To this end, increased attention has been directed at how anesthetic drugs alter the functional connectivity between brain regions as defined through neuroimaging. However, the effects of anesthesia on temporal dynamics at functional network scales is less well understood. Here, we examine such dynamics in view of the free-energy principle, which postulates that brain dynamics tend to promote lower energy (more organized) states...
2018: Network neuroscience
https://www.readbyqxmd.com/read/29730495/mouse-fmri-under-ketamine-and-xylazine-anesthesia-robust-contralateral-somatosensory-cortex-activation-in-response-to-forepaw-stimulation
#4
Hyun-Ji Shim, Won Beom Jung, Felix Schlegel, Joonsung Lee, Sangwoo Kim, Jungryun Lee, Seong-Gi Kim
Mouse fMRI is critically useful to investigate functions of mouse models. Until now, the somatosensory-evoked responses in anesthetized mice are often widespread and inconsistent across reports. Here, we adopted a ketamine and xylazine mixture for mouse fMRI, which is relatively new anesthetics in fMRI experiments. Forepaw stimulation frequency was optimized using cerebral blood volume (CBV)-weighted optical imaging (n = 11) and blood-oxygenation-level dependent (BOLD) fMRI with a gradient-echo time of 16 ms at 9...
August 15, 2018: NeuroImage
https://www.readbyqxmd.com/read/29690796/spontaneous-bold-waves-a-novel-hemodynamic-activity-in-sprague-dawley-rat-brain-detected-by-functional-magnetic-resonance-imaging
#5
Artem Shatillo, Arto Lipponen, Raimo A Salo, Heikki Tanila, Alexei Verkhratsky, Rashid Giniatullin, Olli H Gröhn
We report spontaneous hemodynamic activity termed "Spontaneous BOLD Waves" (SBWs) detected by BOLD fMRI in Sprague-Dawley rats under medetomidine anesthesia. These SBWs, which lasted several minutes, were observed in cortex, thalamus and hippocampus. The SBWs' correlates were undetectable in electrophysiological recordings, suggesting an exclusive gliovascular phenomenon dissociated from neuronal activity. SBWs were insensitive to the NMDA receptors antagonist MK-801 but were inhibited by the α1-adrenoceptor blocker prazosin...
April 25, 2018: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/29682064/awake-craniotomy-with-noninvasive-brain-mapping-by-3-tesla-functional-magnetic-resonance-imaging-for-excision-of-low-grade-glioma-a-case-of-a-young-patient-from-pakistan
#6
Atta Ul Aleem Bhatti, Nasir Khan Jakhrani, Maria Adnan Parekh
The past few years have seen increasing support for gross total resection in the management of low-grade gliomas (LGGs), with a greater extent of resection correlated with better overall survival, progression-free survival, and time to malignant transformation. There is consistent evidence in literature supporting extent of safe resection as a good prognostic indicator as well as positively affecting seizure control, symptomatic relief in pressure symptoms, and longer progression-free and total survival. The operative goal in most LGG cases is to maximize the extent of resection for these benefits while avoiding postoperative neurologic deficits...
April 2018: Asian Journal of Neurosurgery
https://www.readbyqxmd.com/read/29454935/dynamic-resting-state-fmri-analysis-in-mice-reveals-a-set-of-quasi-periodic-patterns-and-illustrates-their-relationship-with-the-global-signal
#7
REVIEW
Michaël E Belloy, Maarten Naeyaert, Anzar Abbas, Disha Shah, Verdi Vanreusel, Johan van Audekerke, Shella D Keilholz, Georgios A Keliris, Annemie Van der Linden, Marleen Verhoye
Time-resolved 'dynamic' over whole-period 'static' analysis of low frequency (LF) blood-oxygen level dependent (BOLD) fluctuations provides many additional insights into the macroscale organization and dynamics of neural activity. Although there has been considerable advancement in the development of mouse resting state fMRI (rsfMRI), very little remains known about its dynamic repertoire. Here, we report for the first time the detection of a set of recurring spatiotemporal Quasi-Periodic Patterns (QPPs) in mice, which show spatial similarity with known resting state networks...
October 15, 2018: NeuroImage
https://www.readbyqxmd.com/read/29212921/bold-temporal-variability-differentiates-wakefulness-from-anesthesia-induced-unconsciousness
#8
Alexis T Baria, Maria V Centeno, Mariam E Ghantous, Pei C Chang, Daniele Procissi, A Vania Apkarian
Even though a number of findings, based on information content or information integration, are shown to define neural underpinnings characteristic of a conscious experience, the neurophysiological mechanism of consciousness is still poorly understood. Here, we investigated the brain activity and functional connectivity changes that occur in the isoflurane-anesthetized unconscious state in contrast to the awake state in rats (awake and/or anesthetized, n = 68 rats). We examined nine information measures previously shown to distinguish between conscious states: blood oxygen level-dependent (BOLD) variability, functional connectivity strength, modularity, weighted modularity, efficiency, clustering coefficient, small-worldness, and spatial and temporal Lempel-Ziv complexity measure...
March 1, 2018: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28729926/coherence-of-bold-signal-and-electrical-activity-in-the-human-brain-during-deep-sevoflurane-anesthesia
#9
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/28441420/mapping-of-the-brain-hemodynamic-responses-to-sensorimotor-stimulation-in-a-rodent-model-a-bold-fmri-study
#10
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/28406906/water-diffusion-closely-reveals-neural-activity-status-in-rat-brain-loci-affected-by-anesthesia
#11
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/28274833/investigating-the-spatiotemporal-characteristics-of-the-deoxyhemoglobin-related-and-deoxyhemoglobin-unrelated-functional-hemodynamic-response-across-cortical-layers-in-awake-marmosets
#12
Cecil Chern-Chyi Yen, Daniel Papoti, Afonso C Silva
Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) has become a major tool to map neural activity. However, the spatiotemporal characteristics of the BOLD functional hemodynamic response across the cortical layers remain poorly understood. While human fMRI studies suffer from low spatiotemporal resolution, the use of anesthesia in animal models introduces confounding factors. Additionally, inflow contributions to the fMRI signal become non-negligible when short repetition times (TRs) are used...
January 1, 2018: NeuroImage
https://www.readbyqxmd.com/read/28082871/sevoflurane-alters-spatiotemporal-functional-connectivity-motifs-that-link-resting-state-networks-during-wakefulness
#13
MohammadMehdi Kafashan, ShiNung Ching, Ben J A Palanca
Background: The spatiotemporal patterns of correlated neural activity during the transition from wakefulness to general anesthesia have not been fully characterized. Correlation analysis of blood-oxygen-level dependent (BOLD) functional magnetic resonance imaging (fMRI) allows segmentation of the brain into resting-state networks (RSNs), with functional connectivity referring to the covarying activity that suggests shared functional specialization. We quantified the persistence of these correlations following the induction of general anesthesia in healthy volunteers and assessed for a dynamic nature over time...
2016: Frontiers in Neural Circuits
https://www.readbyqxmd.com/read/28058981/water-apparent-diffusion-coefficient-correlates-with-gamma-oscillation-of-local-field-potentials-in-the-rat-brain-nucleus-accumbens-following-alcohol-injection
#14
Tomokazu Tsurugizawa, Yoshifumi Abe, Denis Le Bihan
Ethanol is a vasoactive agent as well as psychoactive drug. The neurovascular response, coupled with neuronal activity, can be disturbed by alcohol intake. Hence, blood oxygenation level-dependent (BOLD) fMRI, which relies on neurovascular coupling, might not be reliable to reflect alcohol-induced neuronal responses. Recently, diffusion fMRI has been shown to be more sensitive to neural activity than BOLD fMRI even when neurovascular coupling is disrupted. Especially, the apparent diffusion coefficient (ADC) is sensitive to changes occurring in the cellular tissue structure upon activation...
September 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/27908788/time-to-wake-up-studying-neurovascular-coupling-and-brain-wide-circuit-function-in-the-un-anesthetized-animal
#15
REVIEW
Yu-Rong Gao, Yuncong Ma, Qingguang Zhang, Aaron T Winder, Zhifeng Liang, Lilith Antinori, Patrick J Drew, Nanyin Zhang
Functional magnetic resonance imaging (fMRI) has allowed the noninvasive study of task-based and resting-state brain dynamics in humans by inferring neural activity from blood-oxygenation-level dependent (BOLD) signal changes. An accurate interpretation of the hemodynamic changes that underlie fMRI signals depends on the understanding of the quantitative relationship between changes in neural activity and changes in cerebral blood flow, oxygenation and volume. While there has been extensive study of neurovascular coupling in anesthetized animal models, anesthesia causes large disruptions of brain metabolism, neural responsiveness and cardiovascular function...
June 2017: NeuroImage
https://www.readbyqxmd.com/read/27774631/resting-state-functional-mri-as-a-tool-for-evaluating-brain-hemodynamic-responsiveness-to-external-stimuli-in-rats
#16
Jaakko Paasonen, Raimo A Salo, Joanna K Huttunen, Olli Gröhn
PURPOSE: Anesthesia is a major confounding factor in functional MRI (fMRI) experiments attributed to its effects on brain function. Recent evidence suggests that parameters obtained with resting-state fMRI (rs-fMRI) are coupled with anesthetic depth. Therefore, we investigated whether parameters obtained with rs-fMRI, such as functional connectivity (FC), are also directly related to blood-oxygen-level-dependent (BOLD) responses. METHODS: A simple rs-fMRI protocol was implemented in a pharmacological fMRI study to evaluate the coupling between hemodynamic responses and FC under five anesthetics (α-chloralose, isoflurane, medetomidine, thiobutabarbital, and urethane)...
September 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27591109/eyeblink-classical-conditioning-and-bold-fmri-of-anesthesia-induced-changes-in-the-developing-brain
#17
Daniil P Aksenov, Michael J Miller, Limin Li, Alice M Wyrwicz
Millions of children undergo general anesthesia each year in the USA alone, and a growing body of literature from animals and humans suggests that exposure to anesthesia at an early age can impact neuronal development, leading to learning and memory impairments later in childhood. Although a number of studies have reported behavioral and structural effects of anesthesia exposure during infancy, the functional manifestation of these changes has not been previous examined. In this study we used BOLD fMRI to measure the functional response to stimulation in the whisker barrel cortex of awake rabbits before and after learning a trace eyeblink classical conditioning paradigm...
December 1, 2016: Physiology & Behavior
https://www.readbyqxmd.com/read/27520750/chronic-psychosocial-stress-in-mice-leads-to-changes-in-brain-functional-connectivity-and-metabolite-levels-comparable-to-human-depression
#18
Joanes Grandjean, Damiano Azzinnari, Aline Seuwen, Hannes Sigrist, Erich Seifritz, Christopher R Pryce, Markus Rudin
Human depression, for which chronic psychosocial stress is a major risk factor, is characterized by consistent alterations in neurocircuitry. For example, there is increased functional connectivity (FC) within and between regions comprising the default mode network (DMN) including prefrontal cortex and cingulate cortex. Alterations in network FC are associated with specific aspects of psychopathology. In mice, chronic psychosocial stress (CPS) leads to depression-relevant behavior, including increased fear learning, learned helplessness, fatigue and decreased motivation for reward...
November 15, 2016: NeuroImage
https://www.readbyqxmd.com/read/27451405/effects-of-anesthesia-on-resting-state-bold-signals-in-white-matter-of-non-human-primates
#19
Tung-Lin Wu, Feng Wang, Adam W Anderson, Li Min Chen, Zhaohua Ding, John C Gore
Resting state functional magnetic resonance imaging (rsfMRI) has been widely used to measure functional connectivity between cortical regions of the brain. However, there have been minimal reports of bold oxygenation level dependent (BOLD) signals in white matter, and even fewer attempts to detect resting state connectivity. Recently, there has been growing evidence that suggests that reliable detection of white matter BOLD signals may be possible. We have previously shown that nearest neighbor inter-voxel correlations of resting state BOLD signal fluctuations in white matter are anisotropic and can be represented by a functional correlation tensor, but the biophysical origins of these signal variations are not clear...
November 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27291459/propofol-anesthesia-reduces-lempel-ziv-complexity-of-spontaneous-brain-activity-in-rats
#20
Anthony G Hudetz, Xiping Liu, Siveshigan Pillay, Melanie Boly, Giulio Tononi
Consciousness is thought to scale with brain complexity, and it may be diminished in anesthesia. Lempel-Ziv complexity (LZC) of field potentials has been shown to be a promising measure of the level of consciousness in anesthetized human subjects, neurological patients, and across the sleep-wake states in rats. Whether this relationship holds for intrinsic networks obtained by functional brain imaging has not been tested. To fill this gap of knowledge, we estimated LZC from large-scale dynamic analysis of functional magnetic resonance images (fMRI) in conscious sedated and unconscious anesthetized rats...
August 15, 2016: Neuroscience Letters
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