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functional connectivity under anesthesia

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https://www.readbyqxmd.com/read/30090873/high-energy-brain-dynamics-during-anesthesia-induced-unconsciousness
#1
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/30067128/isoflurane-and-ketamine-differentially-influence-spontaneous-and-evoked-laminar-electrophysiology-in-mouse-v1
#2
Nicholas J Michelson, Takashi Daniel Yoshida Kozai
General anesthesia is ubiquitous in research and medicine, yet although the molecular mechanisms of anesthetics are well characterized, their ultimate influence on cortical electrophysiology remains unclear. Moreover, the influence that different anesthetics have on sensory cortices at neuronal and ensemble scales is mostly unknown, and represents an important gap in knowledge that has widespread relevance for neural sciences. To address this knowledge gap, this work explored the effects of isoflurane and ketamine/xylazine, two widely used anesthetic paradigms, on electrophysiological behavior in mouse primary visual cortex...
August 1, 2018: Journal of Neurophysiology
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
#3
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/29788295/intrinsic-functional-connectivity-resembles-cortical-architecture-at-various-levels-of-isoflurane-anesthesia
#4
Felix Fischer, Florian Pieper, Edgar Galindo-Leon, Gerhard Engler, Claus C Hilgetag, Andreas K Engel
Cortical single neuron activity and local field potential patterns change at different depths of general anesthesia. Here, we investigate the associated network level changes of functional connectivity. We recorded ongoing electrocorticographic (ECoG) activity from temporo-parieto-occipital cortex of 6 ferrets at various levels of isoflurane/nitrous oxide anesthesia and determined functional connectivity by computing amplitude envelope correlations. Through hierarchical clustering, we derived typical connectivity patterns corresponding to light, intermediate and deep anesthesia...
August 1, 2018: Cerebral Cortex
https://www.readbyqxmd.com/read/29771718/evaluation-of-drug-effects-on-cerebral-blood-flow-and-glucose-uptake-in-un-anesthetized-and-un-stimulated-rats-application-of-free-moving-apparatus-enabling-to-keep-rats-free-during-pet-spect-tracer-injection-and-uptake
#5
Taku Sugita, Yusuke Kondo, Seigo Ishino, Ikuo Mori, Takashi Horiguchi, Mikako Ogawa, Yasuhiro Magata
OBJECTIVES: The purpose of this study is the development of novel fluorine-18-fluorodeoxyglucose (F-FDG)-PET and Tc-hexamethylpropylene amine oxime (HMPAO) SPECT methods with free-moving apparatus on conscious rats to investigate brain activity without the effects of anesthesia and tactual stimulation. We also assessed the sensitivity of the experimental system by an intervention study using fluoxetine as a reference drug. MATERIALS AND METHODS: A catheter was inserted into the femoral vein and connected to a free-moving cannula system...
August 2018: Nuclear Medicine Communications
https://www.readbyqxmd.com/read/29734894/-in-situ-vascular-nerve-graft-for-restoration-of-intrinsic-hand-function-an-anatomical-study
#6
Kamran Mozaffarian, Hamid Reza Zemoodeh, Mohammad Zarenezhad, Mohammad Owji
BACKGROUND: In combined high median and ulnar nerve injury, transfer of the posterior interosseous nerve branches to the motor branch of the ulnar nerve (MUN) is previously described in order to restore intrinsic hand function. In this operation a segment of sural nerve graft is required to close the gap between the donor and recipient nerves. However the thenar muscles are not innervated by this nerve transfer. The aim of the present study was to evaluate whether the superficial radial nerve (SRN) can be used as an "in situ vascular nerve graft" to connect the donor nerves to the MUN and the motor branch of median nerve (MMN) at the same time in order to address all denervated intrinsic and thenar muscles...
June 2018: Journal of Hand Surgery Asian-Pacific Volume
https://www.readbyqxmd.com/read/29730495/mouse-fmri-under-ketamine-and-xylazine-anesthesia-robust-contralateral-somatosensory-cortex-activation-in-response-to-forepaw-stimulation
#7
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/29713266/the-effect-of-single-pyramidal-neuron-firing-within-layer-2-3-and-layer-4-in-mouse-v1
#8
Jochen F Meyer, Peyman Golshani, Stelios M Smirnakis
The influence of cortical cell spiking activity on nearby cells has been studied extensively in vitro . Less is known, however, about the impact of single cell firing on local cortical networks in vivo . In a pioneering study, Kwan and Dan (Kwan and Dan, 2012) reported that in mouse layer 2/3 (L2/3), under anesthesia , stimulating a single pyramidal cell recruits ~2.1% of neighboring units. Here we employ two-photon calcium imaging in layer 2/3 of mouse V1, in conjunction with single-cell patch clamp stimulation in layer 2/3 or layer 4, to probe, in both the awake and lightly anesthetized states , how (i) activating single L2/3 pyramidal neurons recruits neighboring units within L2/3 and from layer 4 (L4) to L2/3, and whether (ii) activating single pyramidal neurons changes population activity in local circuit...
2018: Frontiers in Neural Circuits
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
#9
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
#10
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...
February 15, 2018: NeuroImage
https://www.readbyqxmd.com/read/29414498/functional-connectivity-under-six-anesthesia-protocols-and-the-awake-condition-in-rat-brain
#11
Jaakko Paasonen, Petteri Stenroos, Raimo A Salo, Vesa Kiviniemi, Olli Gröhn
Resting-state functional magnetic resonance imaging (rsfMRI) is a translational imaging method with great potential in several neurobiologic applications. Most preclinical rsfMRI studies are performed in anesthetized animals, but the confounding effects of anesthesia on the measured functional connectivity (FC) are poorly understood. Therefore, we measured FC under six commonly used anesthesia protocols and compared the findings with data obtained from awake rats. The results demonstrated that each anesthesia protocol uniquely modulated FC...
May 15, 2018: NeuroImage
https://www.readbyqxmd.com/read/29324934/stem-cells-therapy-the-future-in-the-management-of-systemic-sclerosis-a-case-report
#12
Jung In Song, Silvanie Volz, Maria Eirini Liodaki, Peter Mailänder, Konstantinos Kalousis
OBJECTIVE: Systemic sclerosis (SSc) is a connective tissue disorder of unknown etiology, with heterogeneous clinical manifestations and chronic and often progressive course. The diffuse cutaneous form of SSc (dcSSc) is characterized by thickening of the skin (scleroderma) and distinctive involvement of multiple internal organs. Patients with limited cutaneous SSc (lcSSc) generally have long-standing Raynaud's phenomenon before other manifestations of SSc appear. Over the last decade the Interest of adipose-derived cell therapy in regenerative medicine has increased continuously...
September 2017: Hellenic Journal of Nuclear Medicine
https://www.readbyqxmd.com/read/29212921/bold-temporal-variability-differentiates-wakefulness-from-anesthesia-induced-unconsciousness
#13
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/29121108/spatio-temporal-dynamics-of-multimodal-eeg-fnirs-signals-in-the-loss-and-recovery-of-consciousness-under-sedation-using-midazolam-and-propofol
#14
Seul-Ki Yeom, Dong-Ok Won, Seong In Chi, Kwang-Suk Seo, Hyun Jeong Kim, Klaus-Robert Müller, Seong-Whan Lee
On sedation motivated by the clinical needs for safety and reliability, recent studies have attempted to identify brain-specific signatures for tracking patient transition into and out of consciousness, but the differences in neurophysiological effects between 1) the sedative types and 2) the presence/absence of surgical stimulations still remain unclear. Here we used multimodal electroencephalography-functional near-infrared spectroscopy (EEG-fNIRS) measurements to observe electrical and hemodynamic responses during sedation simultaneously...
2017: PloS One
https://www.readbyqxmd.com/read/29106499/autism-related-neuroligin-4-knockout-impairs-intracortical-processing-but-not-sensory-inputs-in-mouse-barrel-cortex
#15
Petr Unichenko, Jenq-Wei Yang, Sergei Kirischuk, Sergei Kolbaev, Werner Kilb, Matthieu Hammer, Dilja Krueger-Burg, Nils Brose, Heiko J Luhmann
Neuroligin-4 (Nlgn4) is a cell adhesion protein that regulates synapse organization and function. Mutations in human NLGN4 are among the causes of autism spectrum disorders. In mouse, Nlgn4 knockout (KO) perturbs GABAergic synaptic transmission and oscillatory activity in hippocampus, and causes social interaction deficits. The complex profile of cellular and circuit changes that are caused by Nlgn4-KO is still only partly understood. Using Nlgn4-KO mice, we found that Nlgn4-KO increases the power in the alpha frequency band of spontaneous network activity in the barrel cortex under urethane anesthesia in vivo...
August 1, 2018: Cerebral Cortex
https://www.readbyqxmd.com/read/29068830/propofol-induced-changes-in-%C3%AE-%C3%AE-sensorimotor-cortical-connectivity
#16
Mahsa Malekmohammadi, Nicholas AuYong, Collin M Price, Evangelia Tsolaki, Andrew E Hudson, Nader Pouratian
BACKGROUND: Anesthetics are believed to alter functional connectivity across brain regions. However, network-level analyses of anesthesia, particularly in humans, are sparse. The authors hypothesized that propofol-induced loss of consciousness results in functional disconnection of human sensorimotor cortices underlying the loss of volitional motor responses. METHODS: The authors recorded local field potentials from sensorimotor cortices in patients with Parkinson disease (N = 12) and essential tremor (N = 7) undergoing deep brain stimulation surgery, before and after propofol-induced loss of consciousness...
February 2018: Anesthesiology
https://www.readbyqxmd.com/read/29058592/ureteral-reconstruction-using-a-tapered-non-vascularized-bladder-graft-an-experimental-study-in-a-canine-animal-model
#17
Lujia Zou, Shanhua Mao, Shenghua Liu, Limin Zhang, Tian Yang, Yun Hu, Qiang Ding, Haowen Jiang
BACKGROUND: Reconstruction of ureteral defects and strictures remains problematic for urologists. We aimed to investigate the possibility of a tapered non-vascularized bladder graft as a novel substitute for ureteral reconstruction. METHODS: This experimental study was conducted on nine beagles. Under general anesthesia, a full-thickness graft with 5-6 cm in length was disassociated from the anterior upper wall of the bladder, and tapered into 1/3 to 1/2 thickness, remaining the urothelial surface...
October 23, 2017: BMC Urology
https://www.readbyqxmd.com/read/28955209/bi-directional-theta-modulation-between-the-septo-hippocampal-system-and-the-mammillary-area-in-free-moving-rats
#18
Ming Ruan, Calvin K Young, Neil McNaughton
Hippocampal (HPC) theta oscillations have long been linked to various functions of the brain. Many cortical and subcortical areas that also exhibit theta oscillations have been linked to functional circuits with the hippocampus on the basis of coupled activities at theta frequencies. We examine, in freely moving rats, the characteristics of diencephalic theta local field potentials (LFPs) recorded in the supramammillary/mammillary (SuM/MM) areas that are bi-directionally connected to the HPC through the septal complex...
2017: Frontiers in Neural Circuits
https://www.readbyqxmd.com/read/28927746/-proposal-of-screening-for-diffuse-low-grade-gliomas-in-the-population-from-20-to-40years
#19
Emmanuel Mandonnet, Luc Taillandier, Hugues Duffau
Diffuse low-grade gliomas (DLGG) are cerebral tumors occurring in young adults, with an inescapable progression to higher grade of malignancy, resulting in functional impairment and death. DLGG evolve in several phases: an asymptomatic period despite a slow radiological growth; a period in which inaugural symptoms occur, usually epilepsy with possible mild cognitive disorders; then a phase with malignant transformation generating disabling neurological deficits; and ultimately the terminal stage. Early maximal surgical resection significantly increases overall survival while preserving quality of life...
October 2017: La Presse Médicale
https://www.readbyqxmd.com/read/28634149/a-non-invasive-restraining-system-for-awake-mouse-imaging
#20
Dan Madularu, Axel P Mathieu, Chathura Kumaragamage, Lauren M Reynolds, Jamie Near, Cecilia Flores, M Natasha Rajah
BACKGROUND: Preclinical neuroimaging allows for the assessment of brain anatomy, connectivity and function in laboratory animals, such as mice and rats. Most of these studies are performed under anesthesia to avoid movement during the scanning sessions. METHOD: Due to the limitations associated with anesthetized imaging, recent efforts have been made to conduct rodent imaging studies in awake animals, habituated to the restraint systems used in these instances. As of now, only one such system is commercially available for mouse scanning (Animal Imaging Research, Boston, MA, USA) integrating the radiofrequency coil electronics with the restraining element, an approach which, although effective in reducing head motion during awake imaging, has some limitations...
August 1, 2017: Journal of Neuroscience Methods
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