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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/30029990/new-insights-into-the-pathophysiology-of-postoperative-hemorrhage-in-thyroid-surgery-an-experimental-study-in-a-porcine-model
#4
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
https://www.readbyqxmd.com/read/30028727/resting-state-dynamics-as-a-cortical-signature-of-anesthesia-in-monkeys
#5
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)...
July 20, 2018: Anesthesiology
https://www.readbyqxmd.com/read/30004907/breakdown-of-neural-function-under-isoflurane-anesthesia-in-vivo-multineuronal-imaging-in-caenorhabditis-elegans
#6
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
https://www.readbyqxmd.com/read/30002419/increasing-isoflurane-dose-reduces-homotopic-correlation-and-functional-segregation-of-brain-networks-in-mice-as-revealed-by-resting-state-fmri
#7
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
https://www.readbyqxmd.com/read/29974570/disrupted-neural-variability-during-propofol-induced-sedation-and-unconsciousness
#8
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
https://www.readbyqxmd.com/read/29878344/resting-state-functional-connectivity-after-sphenopalatine-ganglion-blocks-in-chronic-migraine-with-medication-overuse-headache-a-pilot-longitudinal-fmri-study
#9
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
https://www.readbyqxmd.com/read/29755332/neurofeedback-and-the-neural-representation-of-self-lessons-from-awake-state-and-sleep
#10
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
https://www.readbyqxmd.com/read/29730495/mouse-fmri-under-ketamine-and-xylazine-anesthesia-robust-contralateral-somatosensory-cortex-activation-in-response-to-forepaw-stimulation
#11
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
#12
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
#13
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/29606579/spontaneous-infra-slow-brain-activity-has-unique-spatiotemporal-dynamics-and-laminar-structure
#14
Anish Mitra, Andrew Kraft, Patrick Wright, Benjamin Acland, Abraham Z Snyder, Zachary Rosenthal, Leah Czerniewski, Adam Bauer, Lawrence Snyder, Joseph Culver, Jin-Moo Lee, Marcus E Raichle
Systems-level organization in spontaneous infra-slow (<0.1Hz) brain activity, measured using blood oxygen signals in fMRI and optical imaging, has become a major theme in the study of neural function in both humans and animal models. Yet the neurophysiological basis of infra-slow activity (ISA) remains unresolved. In particular, is ISA a distinct physiological process, or is it a low-frequency analog of faster neural activity? Here, using whole-cortex calcium/hemoglobin imaging in mice, we show that ISA in each of these modalities travels through the cortex along stereotypical spatiotemporal trajectories that are state dependent (wake versus anesthesia) and distinct from trajectories in delta (1-4 Hz) activity...
April 18, 2018: Neuron
https://www.readbyqxmd.com/read/29600499/isoflurane-anesthesia-does-not-affect-spinal-cord-neurovascular-coupling-evidence-from-decerebrated-rats
#15
Thierry Paquette, Hugues Leblond, Mathieu Piché
Neurological examination remains the primary clinical investigation in patients with spinal cord injury. However, neuroimaging methods such as functional magnetic resonance imaging (fMRI) are promising tools for following functional changes in the course of injury, disease and rehabilitation. However, the relationship between neuronal activity and blood flow in the spinal cord on which fMRI relies has been largely overlooked. The objective of this study was to examine neurovascular coupling in the spinal cord of decerebrated rats during electrical stimulation of the sciatic nerve with and without isoflurane anesthesia (1...
March 29, 2018: Journal of Physiological Sciences: JPS
https://www.readbyqxmd.com/read/29524643/sequential-variation-in-brain-functional-magnetic-resonance-imaging-after-peripheral-nerve-injury-a-rat-study
#16
Okihiro Onishi, Kazuya Ikoma, Ryo Oda, Tetsuro Yamazaki, Hiroyoshi Fujiwara, Shunji Yamada, Masaki Tanaka, Toshikazu Kubo
Although treatment protocols are available, patients experience both acute neuropathic pain and chronic neuropathic pain, hyperalgesia, and allodynia after peripheral nerve injury. The purpose of this study was to identify the brain regions activated after peripheral nerve injury using functional magnetic resonance imaging (fMRI) sequentially and assess the relevance of the imaging results using histological findings. To model peripheral nerve injury in male Sprague-Dawley rats, the right sciatic nerve was crushed using an aneurysm clip, under general anesthesia...
April 23, 2018: Neuroscience Letters
https://www.readbyqxmd.com/read/29486001/comparison-of-nrem-sleep-and-intravenous-sedation-through-local-information-processing-and-whole-brain-network-to-explore-the-mechanism-of-general-anesthesia
#17
COMPARATIVE STUDY
Yun Li, Shengpei Wang, Chuxiong Pan, Fushan Xue, Junfang Xian, Yaqi Huang, Xiaoyi Wang, Tianzuo Li, Huiguang He
BACKGROUND: The mechanism of general anesthesia (GA) has been explored for hundreds of years, but unclear. Previous studies indicated a possible correlation between NREM sleep and GA. The purpose of this study is to compare them by in vivo human brain function to probe the neuromechanism of consciousness, so as to find out a clue to GA mechanism. METHODS: 24 healthy participants were equally assigned to sleep or propofol sedation group by sleeping ability. EEG and Ramsay Sedation Scale were applied to determine sleep stage and sedation depth respectively...
2018: PloS One
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
#18
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/29439328/impact-of-total-knee-arthroplasty-with-general-anesthesia-on-brain-networks-cognitive-efficiency-and-ventricular-volume-predict-functional-connectivity-decline-in-older-adults
#19
Haiqing Huang, Jared Tanner, Hari Parvataneni, Mark Rice, Ann Horgas, Mingzhou Ding, Catherine Price
 Using resting state functional magnetic resonance imaging (RS-fMRI), we explored: 1) pre- to post-operative changes in functional connectivity in default mode, salience, and central executive networks after total knee arthroplasty (TKA) with general anesthesia, and 2) the contribution of cognitive/brain reserve metrics these resting state functional declines. Individuals age 60 and older electing unilateral total knee arthroplasty (TKA; n = 48) and non-surgery peers with osteoarthritis (n = 45) completed baseline cognitive testing and baseline and post-surgery (post-baseline, 48-h post-surgery) brain MRI...
2018: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/29421324/effects-of-propofol-anesthesia-on-the-processing-of-noxious-stimuli-in-the-spinal-cord-and-the-brain
#20
Gregor Lichtner, Ryszard Auksztulewicz, Evgeniya Kirilina, Helena Velten, Dionysios Mavrodis, Michael Scheel, Felix Blankenburg, Falk von Dincklage
Drug-induced unconsciousness is an essential component of general anesthesia, commonly attributed to attenuation of higher-order processing of external stimuli and a resulting loss of information integration capabilities of the brain. In this study, we investigated how the hypnotic drug propofol at doses comparable to those in clinical practice influences the processing of somatosensory stimuli in the spinal cord and in primary and higher-order cortices. Using nociceptive reflexes, somatosensory evoked potentials and functional magnet resonance imaging (fMRI), we found that propofol abolishes the processing of innocuous and moderate noxious stimuli at low to medium concentration levels, but that intense noxious stimuli evoked spinal and cerebral responses even during deep propofol anesthesia that caused profound electroencephalogram (EEG) burst suppression...
May 15, 2018: NeuroImage
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