scholarly journals High-energy brain dynamics during anesthesia-induced unconsciousness

2017 ◽  
Vol 1 (4) ◽  
pp. 431-445 ◽  
Author(s):  
James R. Riehl ◽  
Ben J. Palanca ◽  
ShiNung Ching
Keyword(s):  
General Anesthesia ◽  
Lower Energy ◽  
Temporal Dynamics ◽  
High Energy ◽  
Brain Network ◽  
Brain Dynamics ◽  
Energy Principle ◽  
Eyes Closed ◽  
Anesthetic Drugs ◽  
Energy States

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. We specifically engaged the hypothesis that such low-energy states play an important role in maintaining conscious awareness. To investigate this hypothesis, we analyzed resting-state BOLD fMRI data from human volunteers during wakefulness and under sevoflurane general anesthesia. Our approach, which extends an idea previously used in the characterization of neuron-scale populations, involves thresholding the BOLD time series and using a normalized Hamiltonian energy function derived from the Ising model. Our major finding is that the brain spends significantly more time in lower energy states during eyes-closed wakefulness than during general anesthesia. This effect is especially pronounced in networks thought to be critical for maintaining awareness, suggesting a crucial cognitive role for both the structure and the dynamical landscape of these networks.

scholarly journals Measurement of the structure of potential cluster bands and absolute branching ratios of high-energy states in 18O*

2020 ◽  
Vol 1643 ◽  
pp. 012155
Author(s):  
S. Pirrie ◽  
C. Wheldon ◽  
Tz. Kokalova ◽  
J. Bishop ◽  
R. Hertenberger ◽  
...  
Keyword(s):  
High Energy ◽  
Branching Ratios ◽  
Energy States

scholarly journals Upconversion emissions from high-energy states of Eu^3+ sensitized by Yb^3+ and Ho^3+ in β-NaYF_4 microcrystals under 980 nm excitation

2011 ◽  
Vol 19 (25) ◽  
pp. 25471 ◽  
Author(s):  
Lili Wang ◽  
Zhenyu Liu ◽  
Zhe Chen ◽  
Dan Zhao ◽  
Guanshi Qin ◽  
...  
Keyword(s):  
High Energy ◽  
Energy States ◽  
Upconversion Emissions

scholarly journals Olfactory Dysfunction After Oral and Maxillofacial Surgery

2021 ◽  
Author(s):  
Yaxi Wang ◽  
Hua Li ◽  
Xuanping Huang ◽  
Nuo Zhou
Keyword(s):  
General Anesthesia ◽  
Nasal Septum ◽  
Rare Complication ◽  
Nasotracheal Intubation ◽  
Maxillofacial Surgery ◽  
Olfactory Dysfunction ◽  
Oral And Maxillofacial Surgery ◽  
General Anesthetic ◽  
Anesthetic Drugs ◽  
Nasal Septum Deviation

Abstract Background: Although anesthesia can contribute to olfactory dysfunction, it is a rare complication after oral and maxillofacial surgery by general anesthesia.Cases presentation: In this study, we introduced 3 cases of patient suffering from anosmia (complete loss of smell), after oral and maxillofacial surgery by general anesthesia. We also investigated possible etiologies of anosmia. Conclusions: There are some evidences that anosmia is caused by nasotracheal intubation, which may cause OM injury and/or swing of the nasal septum in patients with nasal septum deviation. Olfactory dysfunction via general anesthetic drugs, however, may have a different etiology.

scholarly journals Negative energy states in the Reissner–Nordström metric

2021 ◽  
pp. 2150120
Author(s):  
O. B. Zaslavskii
Keyword(s):  
Turning Point ◽  
High Energy ◽  
Negative Energy ◽  
Infinite Chain ◽  
White Hole ◽  
Negative Energy States ◽  
Energy Formula ◽  
High Energy Collisions ◽  
Energy States

We consider electrogeodesics on which the energy [Formula: see text] in the Reissner–Nordström metric. It is shown that outside the horizon there is exactly one turning point inside the ergoregion for such particles. This entails that such a particle passes through an infinite chain of black–white hole regions or terminates in the singularity. These properties are relevant for two scenarios of high energy collisions in which the presence of white holes is essential.

scholarly journals Age-dependent electroencephalogram (EEG) patterns during sevoflurane general anesthesia in infants

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Laura Cornelissen ◽  
Seong-Eun Kim ◽  
Patrick L Purdon ◽  
Emery N Brown ◽  
Charles B Berde
Keyword(s):  
General Anesthesia ◽  
Temporal Dynamics ◽  
Brain Activity ◽  
Body Movement ◽  
Video Recording ◽  
Brain State ◽  
Alpha Power ◽  
State Monitoring ◽  
Spatio Temporal ◽  
Electroencephalogram Eeg

Electroencephalogram (EEG) approaches may provide important information about developmental changes in brain-state dynamics during general anesthesia. We used multi-electrode EEG, analyzed with multitaper spectral methods and video recording of body movement to characterize the spatio-temporal dynamics of brain activity in 36 infants 0–6 months old when awake, and during maintenance of and emergence from sevoflurane general anesthesia. During maintenance: (1) slow-delta oscillations were present in all ages; (2) theta and alpha oscillations emerged around 4 months; (3) unlike adults, all infants lacked frontal alpha predominance and coherence. Alpha power was greatest during maintenance, compared to awake and emergence in infants at 4–6 months. During emergence, theta and alpha power decreased with decreasing sevoflurane concentration in infants at 4–6 months. These EEG dynamic differences are likely due to developmental factors including regional differences in synaptogenesis, glucose metabolism, and myelination across the cortex. We demonstrate the need to apply age-adjusted analytic approaches to develop neurophysiologic-based strategies for pediatric anesthetic state monitoring.

scholarly journals Comparison of Anesthesia Depth Monitoring using Conventional and Bispectral Index on Incidence and Severity of Nausea and Vomiting after Urological Surgeries

2018 ◽  
Vol 6 (2) ◽  
pp. 25
Author(s):  
Reihan Shenasi ◽  
Hamzeh Hoseinzadeh ◽  
Hasan Mohammadpor-Anvari ◽  
Davod Aghamohammadi ◽  
Reza Sari-Motlagh
Keyword(s):  
General Anesthesia ◽  
Bispectral Index ◽  
Postoperative Nausea ◽  
Operating Time ◽  
Postoperative Nausea And Vomiting ◽  
Nausea And Vomiting ◽  
Control Group ◽  
Anesthetic Drugs ◽  
Urological Surgery ◽  
Anesthesia Depth

Bispectral index parameter is used to guide the titration of general anesthesia. This monitoring improves recovery times and hospital discharges, as well as minimizes adverse events. The objective of this study is the comparison of anesthesia depth monitoring by conventional and bispectral index on nausea and vomiting after urological surgery. 180 participants who were scheduled for abdominal urological surgery were studied. Patients before induction of anesthesia were randomize into two groups with and without bispectral index monitoring. Incidence and severity of nausea and vomiting were recorded every 30 minutes for 2 hours and every 6 hours to 24 hours after surgery. The incidence of postoperative nausea and vomiting in Bispectral index group is 14.4% and 8.9% and in control group 28.9% and 23.3%, respectively. The risk of nausea and vomiting after surgery was reduced by 14.5% and 14.4%, respectively in patients monitored with bispectral index.INTRODUCTIONNausea is the conscious perception of medulla stimulation that is associated with vomiting center and create vomiting response (1). General anesthesia with the use of inhalants can cause nausea and vomiting after surgery (Postoperative nausea and vomiting, PONV). The incidence of PONV is reported about 20-30 percent (2). It seems that multiple-factor can cause PONV and few items such as anesthetic drugs, kind of surgery and personal risk factors is effective on PONV. These factors make into two categories that includes factors out of control by anesthesiologists and factors can control by anesthesiologists.1. Factors out of control by anesthesiologists: some of these factors are age, gender, past history of PONV and motion sickness, smoking, kind of surgery, operating time and anesthesia time, anxiety of patients and parents. 2. Factors controlled by anesthesiologists: these factors are associated of anesthesia settings, including premedications, kind of anesthesia, anesthesia drugs during surPublishedby Australian

COMPARISON OF THE EFFECT OF DEXAMETHASONE ON THE BLOOD GLUCOSE LEVEL IN PREGNANT AND NON-PREGNANT WOMEN UNDER GENERAL ANESTHESIA

2021 ◽  
Vol 74 (9) ◽  
pp. 2277-2280
Author(s):  
Hanan Fawzi ◽  
Alaa Hussen Ali
Keyword(s):  
Blood Glucose ◽  
Blood Glucose Level ◽  
General Anesthesia ◽  
Pregnant Women ◽  
Glucose Level ◽  
Elective Cesarean Section ◽  
Glucose Levels ◽  
Anesthetic Drugs ◽  
Study Results ◽  
Blood Glucose Concentrations

The aim: To compared blood glucose concentrations after intravenous injection of dexamethasone in the pregnant and non-pregnant women under general anesthesia. Materials and methods: Eighty patients aged 18-50 years took part in the study (ASA class 1 and 2). Forty of patients were undergoing elective cesarean section under G/A and the other forty undergoing elective laparoscopic Cholecystectomy under G/A. Anesthesia was induced using IV anesthetic drugs (0.5mg/kg ketamine, sleeping dose of propofol up to 2mg/kg, muscle relaxant was 0.6 mg/kg rocuronium and maintained with isoflurane). All of patients have been injected with 0,1mg/kg dexamethasone intravenously, at induction of anesthesia, Blood glucose concentrations were measured at induction and then in 60min, 180min and in 360 min after injection of dexamethasone and results were compared between the groups; IV fluid added was normal saline (0.9%) during the study. Results: Regarding to blood glucose levels, we noticed that its level significantly increased over time and peaked in 180min after dexamethasone injection in both groups. The difference percentage between the lower reading (pre injection) and the upper reading (in 180min after) was 33.5% in pregnant woman and 46.2%for non-pregnant women, this difference was statistically significant relative to the pre injection, as this difference was lower in the pregnant women. In 360min after blood glucose level began to drop in both groups. After giving 0.1 mg/kg of dexamethasone, blood glucose level increased in both groups, but it was lower in pregnant women.

scholarly journals Dynamic Cortical Connectivity during General Anesthesia in Surgical Patients

2019 ◽  
Vol 130 (6) ◽  
pp. 885-897 ◽  
Author(s):  
Phillip E. Vlisides ◽  
Duan Li ◽  
Mackenzie Zierau ◽  
Andrew P. Lapointe ◽  
Ka I. Ip ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
General Anesthesia ◽  
Temporal Dynamics ◽  
Transition Probabilities ◽  
Surgical Patients ◽  
Phase Lag ◽  
Cortical Connectivity ◽  
Single Measure ◽  
Connectivity Patterns ◽  
Weighted Phase Lag Index

Abstract Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background Functional connectivity across the cortex has been posited to be important for consciousness and anesthesia, but functional connectivity patterns during the course of surgery and general anesthesia are unknown. The authors tested the hypothesis that disrupted cortical connectivity patterns would correlate with surgical anesthesia. Methods Surgical patients (n = 53) were recruited for study participation. Whole-scalp (16-channel) wireless electroencephalographic data were prospectively collected throughout the perioperative period. Functional connectivity was assessed using weighted phase lag index. During anesthetic maintenance, the temporal dynamics of connectivity states were characterized via Markov chain analysis, and state transition probabilities were quantified. Results Compared to baseline (weighted phase lag index, 0.163, ± 0.091), alpha frontal–parietal connectivity was not significantly different across the remaining anesthetic and perioperative epochs, ranging from 0.100 (± 0.041) to 0.218 (± 0.136) (P > 0.05 for all time periods). In contrast, there were significant increases in alpha prefrontal–frontal connectivity (peak = 0.201 [0.154, 0.248]; P < 0.001), theta prefrontal–frontal connectivity (peak = 0.137 [0.091, 0.182]; P < 0.001), and theta frontal–parietal connectivity (peak = 0.128 [0.084, 0.173]; P < 0.001) during anesthetic maintenance. Additionally, shifts occurred between states of high prefrontal–frontal connectivity (alpha, beta) with suppressed frontal–parietal connectivity, and high frontal–parietal connectivity (alpha, theta) with reduced prefrontal–frontal connectivity. These shifts occurred in a nonrandom manner (P < 0.05 compared to random transitions), suggesting structured transitions of connectivity during general anesthesia. Conclusions Functional connectivity patterns dynamically shift during surgery and general anesthesia but do so in a structured way. Thus, a single measure of functional connectivity will likely not be a reliable correlate of surgical anesthesia.

scholarly journals Approximate Entropy of Brain Network in the Study of Hemispheric Differences

Entropy ◽  
2020 ◽  
Vol 22 (11) ◽  
pp. 1220
Author(s):  
Francesca Alù ◽  
Francesca Miraglia ◽  
Alessandro Orticoni ◽  
Elda Judica ◽  
Maria Cotelli ◽  
...  
Keyword(s):  
Brain Networks ◽  
Approximate Entropy ◽  
Brain Network ◽  
Hemispheric Differences ◽  
Eyes Closed ◽  
Age Related ◽  
Eeg Recordings ◽  
The Right ◽  
The Impact ◽  
Adult Volunteers

Human brain, a dynamic complex system, can be studied with different approaches, including linear and nonlinear ones. One of the nonlinear approaches widely used in electroencephalographic (EEG) analyses is the entropy, the measurement of disorder in a system. The present study investigates brain networks applying approximate entropy (ApEn) measure for assessing the hemispheric EEG differences; reproducibility and stability of ApEn data across separate recording sessions were evaluated. Twenty healthy adult volunteers were submitted to eyes-closed resting EEG recordings, for 80 recordings. Significant differences in the occipital region, with higher values of entropy in the left hemisphere than in the right one, show that the hemispheres become active with different intensities according to the performed function. Besides, the present methodology proved to be reproducible and stable, when carried out on relatively brief EEG epochs but also at a 1-week distance in a group of 36 subjects. Nonlinear approaches represent an interesting probe to study the dynamics of brain networks. ApEn technique might provide more insight into the pathophysiological processes underlying age-related brain disconnection as well as for monitoring the impact of pharmacological and rehabilitation treatments.

scholarly journals Early alterations of large-scale brain networks temporal dynamics in young children with autism

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Aurélie Bochet ◽  
Holger Franz Sperdin ◽  
Tonia Anahi Rihs ◽  
Nada Kojovic ◽  
Martina Franchini ◽  
...  
Keyword(s):  
Large Scale ◽  
Developmental Stages ◽  
Temporal Dynamics ◽  
Brain Networks ◽  
Autism Spectrum ◽  
Brain Network ◽  
Clustering Methods ◽  
Early Developmental Stages ◽  
Spatio Temporal ◽  
Early Developmental

AbstractAutism spectrum disorders (ASD) are associated with disruption of large-scale brain network. Recently, we found that directed functional connectivity alterations of social brain networks are a core component of atypical brain development at early developmental stages in ASD. Here, we investigated the spatio-temporal dynamics of whole-brain neuronal networks at a subsecond scale in 113 toddlers and preschoolers (66 with ASD) using an EEG microstate approach. We first determined the predominant microstates using established clustering methods. We identified five predominant microstate (labeled as microstate classes A–E) with significant differences in the temporal dynamics of microstate class B between the groups in terms of increased appearance and prolonged duration. Using Markov chains, we found differences in the dynamic syntax between several maps in toddlers and preschoolers with ASD compared to their TD peers. Finally, exploratory analysis of brain–behavioral relationships within the ASD group suggested that the temporal dynamics of some maps were related to conditions comorbid to ASD during early developmental stages.

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