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fmri and anesthesia

Dazhi Yin, Zhao Zhang, Zhiwei Wang, Kristina Zeljic, Qian Lv, Danchao Cai, Yingwei Wang, Zheng Wang
Emerging neuroimaging studies emphasize the dynamic organization of spontaneous brain activity in both human and non-human primates, even under anesthesia. In a recent study, we were able to characterize the heterogeneous architecture of intrinsic functional flexibility in the awake, resting human brain using time-resolved analysis and a probabilistic model. However, it is unknown whether this organizational principle is preserved in the anesthetized monkey brain, and how anesthesia affects dynamic and static measurements of spontaneous brain activity...
2019: Frontiers in Neuroscience
Ekaterina Zhurakovskaya, Juuso Leikas, Tiina Pirttimäki, Francesc Casas Mon, Mikko Gynther, Rubin Aliev, Tomi Rantamäki, Heikki Tanila, Markus M Forsberg, Olli Gröhn, Jaakko Paasonen, Aaro J Jalkanen
Parkinson's disease (PD) is characterized by the gradual degeneration of dopaminergic neurons in the substantia nigra, leading to striatal dopamine depletion. A partial unilateral striatal 6-hydroxydopamine (6-OHDA) lesion causes 40-60% dopamine depletion in the lesioned rat striatum, modeling the early stage of PD. In this study, we explored the connectivity between the brain regions in partially 6-OHDA lesioned male Wistar rats under urethane anesthesia using functional magnetic resonance imaging (fMRI) at 5 weeks after the 6-OHDA infusion...
January 2019: ENeuro
Heonsoo Lee, Zirui Huang, Xiaolin Liu, UnCheol Lee, Anthony G Hudetz
Theoretical consideration predicts that the alteration of local and shared information in the brain is a key element in the mechanism of anesthetic-induced unconsciousness. Ordinal pattern analysis, such as permutation entropy (PE) and symbolic mutual information (SMI), have been successful in quantifying local and shared information in neurophysiological data; however, they have been rarely applied to altered states of consciousness, especially to data obtained with functional magnetic resonance imaging (fMRI)...
July 2018: Entropy
A Demertzi, E Tagliazucchi, S Dehaene, G Deco, P Barttfeld, F Raimondo, C Martial, D Fernández-Espejo, B Rohaut, H U Voss, N D Schiff, A M Owen, S Laureys, L Naccache, J D Sitt
Adopting the framework of brain dynamics as a cornerstone of human consciousness, we determined whether dynamic signal coordination provides specific and generalizable patterns pertaining to conscious and unconscious states after brain damage. A dynamic pattern of coordinated and anticoordinated functional magnetic resonance imaging signals characterized healthy individuals and minimally conscious patients. The brains of unresponsive patients showed primarily a pattern of low interareal phase coherence mainly mediated by structural connectivity, and had smaller chances to transition between patterns...
February 2019: Science Advances
G Bazzu, P A Serra, R Hamelink, M G P Feenstra, I Willuhn, D Denys
BACKGROUND: Translational studies investigating the effects of deep brain stimulation (DBS) on brain function up to now mainly relied on BOLD responses measured with fMRI. However, fMRI studies in rodents face technical and practical limitations (e.g., immobilization, sedation or anesthesia, spatial and temporal resolution of data). Direct measurement of oxygen concentration in the brain using electrochemical sensors is a promising alternative to the use of fMRI. Here, we tested for the first time if such measurements can be combined with DBS...
February 1, 2019: Journal of Neuroscience Methods
Miles Berger, Deborah Oyeyemi, Mobolaji O Olurinde, Heather E Whitson, Kent J Weinhold, Marty G Woldorff, Lewis A Lipsitz, Eugene Moretti, Charles M Giattino, Kenneth C Roberts, Junhong Zhou, Thomas Bunning, Michael Ferrandino, Randall P Scheri, Mary Cooter, Cliburn Chan, Roberto Cabeza, Jeffrey N Browndyke, David M Murdoch, Michael J Devinney, Leslie M Shaw, Harvey Jay Cohen, Joseph P Mathew
BACKGROUND/OBJECTIVES: Every year, up to 40% of the more than 16 million older Americans who undergo anesthesia/surgery develop postoperative cognitive dysfunction (POCD) or delirium. Each of these distinct syndromes is associated with decreased quality of life, increased mortality, and a possible increased risk of Alzheimer's disease. One pathologic process hypothesized to underlie both delirium and POCD is neuroinflammation. The INTUIT study described here will determine the extent to which postoperative increases in cerebrospinal fluid (CSF) monocyte chemoattractant protein 1 (MCP-1) levels and monocyte numbers are associated with delirium and/or POCD and their underlying brain connectivity changes...
January 23, 2019: Journal of the American Geriatrics Society
Zhe Han, Wenjing Chen, Xifan Chen, Kaiwei Zhang, Chuanjun Tong, Xiaoxing Zhang, Chengyu T Li, Zhifeng Liang
Functional magnetic imaging (fMRI) has been widely used to examine the functional neural networks in both the evoked and resting states. However, most fMRI studies in rodents are performed under anesthesia, which greatly limits the scope of their application, and behavioral relevance. Efforts have been made to image rodents in the awake condition, either in the resting state or in response to sensory or optogenetic stimulation. However, fMRI in awake behaving rodents has not yet been achieved. In the current study, a novel fMRI paradigm for awake and behaving mice was developed, allowing functional imaging of the mouse brain in an olfaction-based go/no-go task...
January 3, 2019: NeuroImage
Yang Gao, Pinyi Wang, Meizhen Qian, Jie Zhao, Hangzhe Xu, Xiaotong Zhang
Small animals such as non-human primate (NHP) and rodent are valuable models in frontier neuroscience researches, and comparative research between the animal model and human is helpful to understand and reveal the functional brain circuits in cognition and underlying mechanism in psychological disease. Small animals can be trained or anesthetized to endure long-term and multiple imaging scans; however, the concomitant needs in subcortical structure and function investigations pose major challenges in, e.g., spatial resolution, scan time efficiency, spatial/temporal signal-to-noise-ratio, as well as apparatus mechanical fixation...
December 19, 2018: Physics in Medicine and Biology
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
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
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
Stefan Schopf, Thomas von Ahnen, Martin von Ahnen, Hans Martin Schardey, Ulrich Wirth
BACKGROUND: Postoperative cervical hemorrhage is a rare but life-threatening complication that can cause severe morbidity. Different mechanisms leading to asphyxia have been described based only on clinical observation. METHODS: We performed a series of in vivo animal studies simulating post-thyroidectomy hemorrhage and its effect on respiratory drive. Three series of tests were carried out in 12 German domestic pigs under general anesthesia. The pigs were breathing spontaneously with secured airways...
September 2018: Surgery
Lynn Uhrig, Jacobo D Sitt, Amaury Jacob, Jordy Tasserie, Pablo Barttfeld, Morgan Dupont, Stanislas Dehaene, Bechir Jarraya
WHAT WE ALREADY KNOW ABOUT THIS TOPIC: WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: The mechanism by which anesthetics induce a loss of consciousness remains a puzzling problem. We hypothesized that a cortical signature of anesthesia could be found in an increase in similarity between the matrix of resting-state functional correlations and the anatomical connectivity matrix of the brain, resulting in an increased function-structure similarity. METHODS: We acquired resting-state functional magnetic resonance images in macaque monkeys during wakefulness (n = 3) or anesthesia with propofol (n = 3), ketamine (n = 3), or sevoflurane (n = 3)...
November 2018: Anesthesiology
Mehraj R Awal, Doug Austin, Jeremy Florman, Mark Alkema, Christopher V Gabel, Christopher W Connor
WHAT WE ALREADY KNOW ABOUT THIS TOPIC: WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Previous work on the action of volatile anesthetics has focused at either the molecular level or bulk neuronal measurement such as electroencephalography or functional magnetic resonance imaging. There is a distinct gulf in resolution at the level of cellular signaling within neuronal systems. The authors hypothesize that anesthesia is caused by induced dyssynchrony in cellular signaling rather than suppression of individual neuron activity...
October 2018: Anesthesiology
Q Bukhari, A Schroeter, M Rudin
Effects of anesthetics on brain functional networks are not fully understood. In this work, we investigated functional brain networks derived from resting-state fMRI data obtained under different doses of isoflurane in mice using stationary and dynamic functional connectivity (dFC) analysis. Stationary network analysis using FSL Nets revealed a modular structure of functional networks, which could be segregated into a lateral cortical, an associative cortical network, elements of the prefrontal network, a subcortical network, and a thalamic network...
July 12, 2018: Scientific Reports
Zirui Huang, Jun Zhang, Jinsong Wu, Xiaoge Liu, Jianghui Xu, Jianfeng Zhang, Pengmin Qin, Rui Dai, Zhong Yang, Ying Mao, Anthony G Hudetz, Georg Northoff
Variability quenching is a widespread neural phenomenon in which trial-to-trial variability (TTV) of neural activity is reduced by repeated presentations of a sensory stimulus. However, its neural mechanism and functional significance remain poorly understood. Recurrent network dynamics are suggested as a candidate mechanism of TTV, and they play a key role in consciousness. We thus asked whether the variability-quenching phenomenon is related to the level of consciousness. We hypothesized that TTV reduction would be compromised during reduced level of consciousness by propofol anesthetics...
November 2018: Human Brain Mapping
Kaitlin Krebs, Chris Rorden, X Michelle Androulakis
OBJECTIVE: In this pilot study, the purpose is to investigate if a series of sphenopalatine ganglion (SPG) blockade treatments modulate the functional connectivity within the salience and central executive network (CEN) in chronic migraine with medication overuse headaches (CMw/MOH ). BACKGROUND: Using intranasal local anesthesia to block the SPG for the treatment of various headache disorders has been employed in clinical practice since the early 1900s. However, the exact mechanism of how SPG modulate resting state intrinsic functional brain networks connectivity remains to be elucidated...
May 2018: Headache
Andreas A Ioannides
Neurofeedback has been around for half a century, but despite some promising results it is not yet widely appreciated. Recently, some of the concerns about neurofeedback have been addressed with functional magnetic resonance imaging and magnetoencephalography adding their contributions to the long history of neurofeedback with electroencephalography. Attempts to address other concerns related to methodological issues with new experiments and meta-analysis of earlier studies, have opened up new questions about its efficacy...
2018: Frontiers in Human Neuroscience
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
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
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