Publications of Jean-François BRICHANT
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See detailThe spectral exponent of the resting EEG indexes the presence of consciousness during unresponsiveness induced by propofol, xenon, and ketamine
Colombo, M. A.; Napolitani, Martino; Boly, Mélanie et al

in NeuroImage (2019), 189

Despite the absence of responsiveness during anesthesia, conscious experience may persist. However, reliable, easily acquirable and interpretable neurophysiological markers of the presence of ... [more ▼]

Despite the absence of responsiveness during anesthesia, conscious experience may persist. However, reliable, easily acquirable and interpretable neurophysiological markers of the presence of consciousness in unresponsive states are still missing. A promising marker is based on the decay-rate of the power spectral density (PSD) of the resting EEG. We acquired resting electroencephalogram (EEG) in three groups of healthy participants (n = 5 each), before and during anesthesia induced by either xenon, propofol or ketamine. Dosage of each anesthetic agent was tailored to yield unresponsiveness (Ramsay score = 6). Delayed subjective reports assessed whether conscious experience was present (‘Conscious report’) or absent/inaccessible to recall (‘No Report’). We estimated the decay of the PSD of the resting EEG—after removing oscillatory peaks—via the spectral exponent β, for a broad band (1–40 Hz) and narrower sub-bands (1–20 Hz, 20–40 Hz). Within-subject anesthetic changes in β were assessed. Furthermore, based on β, ‘Conscious report’ states were discriminated against ‘no report’ states. Finally, we evaluated the correlation of the resting spectral exponent with a recently proposed index of consciousness, the Perturbational Complexity Index (PCI), derived from a previous TMS-EEG study. The spectral exponent of the resting EEG discriminated states in which consciousness was present (wakefulness, ketamine) from states where consciousness was reduced or abolished (xenon, propofol). Loss of consciousness substantially decreased the (negative) broad-band spectral exponent in each subject undergoing xenon or propofol anesthesia—indexing an overall steeper PSD decay. Conversely, ketamine displayed an overall PSD decay similar to that of wakefulness—consistent with the preservation of consciousness—yet it showed a flattening of the decay in the high-frequencies (20–40 Hz)—consistent with its specific mechanism of action. The spectral exponent was highly correlated to PCI, corroborating its interpretation as a marker of the presence of consciousness. A steeper PSD of the resting EEG reliably indexed unconsciousness in anesthesia, beyond sheer unresponsiveness. © 2019 The Authors [less ▲]

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See detailThe Edmonton Frail Scale Improves the Prediction of 30-Day Mortality in Elderly Patients Undergoing Cardiac Surgery: A Prospective Observational Study
AMABILI, Philippe ULiege; Wozolek, Aaron ULiege; ROEDIGER, Laurence ULiege et al

in Journal of Cardiothoracic and Vascular Anesthesia (2018)

Objectives: To investigate whether the Edmonton Frail Scale (EFS), a multidimensional frailty assessment tool, improves the prediction of 30-day or in-hospital mortality over the use of the European ... [more ▼]

Objectives: To investigate whether the Edmonton Frail Scale (EFS), a multidimensional frailty assessment tool, improves the prediction of 30-day or in-hospital mortality over the use of the European System for Cardiac Outcome Risk Evaluation (EuroSCORE) II alone. Design: Single-center prospective observational study. Setting: University hospital. Participants: Patients aged 75 years or older undergoing cardiac surgery between February 2014 and May 2017. Intervention: No intervention was performed. The EFS was administered the day before surgery. Measurements and Main Results: The primary endpoint was 30-day or in-hospital mortality. Secondary endpoints were times to discharge from the intensive care unit (ICU) and from the hospital, discharge to a health care facility, and ability to return home by postoperative day 30. The EFS had a good discriminative ability for 30-day mortality (area under the receiver operating characteristic curve = 0.69; 95% confidence interval [CI], 0.56-0.82). Adding frailty, defined by an EFS ≥8, to the EuroSCORE II significantly improved the prediction of 30-day (p = 0.04) mortality. The integrated discrimination index was 0.03 (95% CI, 0.01-0.06, p = 0.01), meaning that the difference in predicted risk between patients who died and those who survived increased by 3% due to the addition of frailty determined by the EFS to the EuroSCORE II. Frailty also was associated significantly with a decreased cumulative probability of discharge from the ICU (p = 0.02) and an increased incidence of discharge to a health care facility (p = 0.01). Conclusion: The EFS has a good predictive ability for 30-day mortality after cardiac surgery in elderly patients and improves the prediction of 30-day mortality over the use of the EuroSCORE II. © 2018 Elsevier Inc. [less ▲]

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See detailIntravenous infusion of lidocaine significantly reduces propofol dose for colonoscopy: a randomised placebo-controlled study
Forster, C.; VANHAUDENHUYSE, Audrey ULiege; GAST, Pierrette ULiege et al

in British Journal of Anaesthesia (2018), 121(5), 1059-1064

Background: Propofol use during sedation for colonoscopy can result in cardiopulmonary complications. Intravenous lidocaine can alleviate visceral pain and decrease propofol requirements during surgery ... [more ▼]

Background: Propofol use during sedation for colonoscopy can result in cardiopulmonary complications. Intravenous lidocaine can alleviate visceral pain and decrease propofol requirements during surgery. We tested the hypothesis that i.v. lidocaine reduces propofol requirements during colonoscopy and improves post-colonoscopy recovery. Methods: Forty patients undergoing colonoscopy were included in this randomised placebo-controlled study. After titration of propofol to produce unconsciousness, patients were given i.v. lidocaine (1.5 mg kg−1 then 4 mg kg−1 h−1) or the same volume of saline. Sedation was standardised and combined propofol and ketamine. The primary endpoint was propofol requirements. Secondary endpoints were: number of oxygen desaturation episodes, endoscopists’ working conditions, discharge time to the recovery room, post-colonoscopy pain, fatigue. Results: Lidocaine infusion resulted in a significant reduction in propofol requirements: 58 (47) vs 121 (109) mg (P=0.02). Doses of ketamine were similar in the two groups: 19 (2) vs 20 (3) mg in the lidocaine and saline groups, respectively. Number of episodes of oxygen desaturation, endoscopists’ comfort, and times for discharge to the recovery room were similar in both groups. Post-colonoscopy pain (P<0.01) and fatigue (P=0.03) were significantly lower in the lidocaine group. Conclusions: Intravenous infusion of lidocaine resulted in a 50% reduction in propofol dose requirements during colonoscopy. Immediate post-colonoscopy pain and fatigue were also improved by lidocaine. Clinical trial registration: NCT 02784860. © 2018 British Journal of Anaesthesia [less ▲]

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See detailDeep neural networks for automatic classification of anesthetic-induced unconsciousness
Patlatzoglou, K.; Chennu, S.; Boly, Mélanie et al

in Lecture Notes in Computer Science (2018), 11309 LNAI

Despite the common use of anesthetics to modulate consciousness in the clinic, brain-based monitoring of consciousness is uncommon. We combined electroencephalographic measurement of brain activity with ... [more ▼]

Despite the common use of anesthetics to modulate consciousness in the clinic, brain-based monitoring of consciousness is uncommon. We combined electroencephalographic measurement of brain activity with deep neural networks to automatically discriminate anesthetic states induced by propofol. Our results with leave-one-participant-out-cross-validation show that convolutional neural networks significantly outperform multilayer perceptrons in discrimination accuracy when working with raw time series. Perceptrons achieved comparable accuracy when provided with power spectral densities. These findings highlight the potential of deep convolutional networks for completely automatic extraction of useful spatio-temporo-spectral features from human EEG. © 2018, Springer Nature Switzerland AG. [less ▲]

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See detailEvoked Alpha Power is Reduced in Disconnected Consciousness During Sleep and Anesthesia
Darracq, M.; Funk, C. M.; Polyakov, D. et al

in Scientific Reports (2018), 8(1),

Sleep and anesthesia entail alterations in conscious experience. Conscious experience may be absent (unconsciousness) or take the form of dreaming, a state in which sensory stimuli are not incorporated ... [more ▼]

Sleep and anesthesia entail alterations in conscious experience. Conscious experience may be absent (unconsciousness) or take the form of dreaming, a state in which sensory stimuli are not incorporated into conscious experience (disconnected consciousness). Recent work has identified features of cortical activity that distinguish conscious from unconscious states; however, less is known about how cortical activity differs between disconnected states and normal wakefulness. We employed transcranial magnetic stimulation–electroencephalography (TMS–EEG) over parietal regions across states of anesthesia and sleep to assess whether evoked oscillatory activity differed in disconnected states. We hypothesized that alpha activity, which may regulate perception of sensory stimuli, is altered in the disconnected states of rapid eye movement (REM) sleep and ketamine anesthesia. Compared to wakefulness, evoked alpha power (8–12 Hz) was decreased during disconnected consciousness. In contrast, in unconscious states of propofol anesthesia and non-REM (NREM) sleep, evoked low-gamma power (30–40 Hz) was decreased compared to wakefulness or states of disconnected consciousness. These findings were confirmed in subjects in which dream reports were obtained following serial awakenings from NREM sleep. By examining signatures of evoked cortical activity across conscious states, we identified novel evidence that suppression of evoked alpha activity may represent a promising marker of sensory disconnection. © 2018, The Author(s). [less ▲]

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See detailPropofol-induced unresponsiveness is associated with impaired feedforward connectivity in cortical hierarchy
Sanders, R. D.; Banks, M. I.; Darracq, M. et al

in British Journal of Anaesthesia (2018), 121(5), 1084-1096

Background: Impaired consciousness has been associated with impaired cortical signal propagation after transcranial magnetic stimulation (TMS). We hypothesised that the reduced current propagation under ... [more ▼]

Background: Impaired consciousness has been associated with impaired cortical signal propagation after transcranial magnetic stimulation (TMS). We hypothesised that the reduced current propagation under propofol-induced unresponsiveness is associated with changes in both feedforward and feedback connectivity across the cortical hierarchy. Methods: Eight subjects underwent left occipital TMS coupled with high-density EEG recordings during wakefulness and propofol-induced unconsciousness. Spectral analysis was applied to responses recorded from sensors overlying six hierarchical cortical sources involved in visual processing. Dynamic causal modelling (DCM) of induced time–frequency responses and evoked response potentials were used to investigate propofol's effects on connectivity between regions. Results: Sensor space analysis demonstrated that propofol reduced both induced and evoked power after TMS in occipital, parietal, and frontal electrodes. Bayesian model selection supported a DCM with hierarchical feedforward and feedback connections. DCM of induced EEG responses revealed that the primary effect of propofol was impaired feedforward responses in cross-frequency theta/alpha–gamma coupling and within frequency theta coupling (F contrast, family-wise error corrected P<0.05). An exploratory analysis (thresholded at uncorrected P<0.001) also suggested that propofol impaired feedforward and feedback beta band coupling. Post hoc analyses showed impairments in all feedforward connections and one feedback connection from parietal to occipital cortex. DCM of the evoked response potential showed impaired feedforward connectivity between left-sided occipital and parietal cortex (T contrast P=0.004, Bonferroni corrected). Conclusions: Propofol-induced loss of consciousness is associated with impaired hierarchical feedforward connectivity assessed by EEG after occipital TMS. © 2018 British Journal of Anaesthesia [less ▲]

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See detailThe role of the oxytocinergic system in pain physiology : new data and possible therapeutic strategies
Saveri, Maximilien ULiege; Stefenatto, Nicolas ULiege; BONHOMME, Vincent ULiege et al

in Acta Anaesthesiologica Belgica (2017), 68(4), 157-166

Pain is an essential subjective warning symptom that can transform into a disease when it becomes chronic and affects the patients’ quality of life. The oxytocinergic system has long been known to play a ... [more ▼]

Pain is an essential subjective warning symptom that can transform into a disease when it becomes chronic and affects the patients’ quality of life. The oxytocinergic system has long been known to play a physiological role in pain perception and its psychological aspects. Despite potential implications for pain treatment, the oxytocinergic system has not yet been therapeutically targeted in clinical practice. This narrative review explores the latest scientific findings on the subject, and discusses some of the unexplored leads for the clinical use of oxytocin in the domain of pain treatment. [less ▲]

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See detailSedation of Patients With Disorders of Consciousness During Neuroimaging: Effects on Resting State Functional Brain Connectivity.
KIRSCH, Murielle ULiege; Guldenmund, Pieter; Bahri, Mohamed Ali ULiege et al

in Anesthesia and Analgesia (2017), 124(2),

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See detailPre-Operative Ability of Clinical Scores to Predict Obstructive Sleep Apnea (OSA) Severity in Susceptible Surgical Patients.
Deflandre, Eric ULiege; Degey, S.; Brichant, Jean-François ULiege et al

in Obesity Surgery (2016)

BACKGROUND: Severe obstructive sleep apnea (OSA) is an independent risk factor for perioperative complications. Clinical scores such as Snoring, Tiredness, Observed apnea, high blood Pressure, Body Mass ... [more ▼]

BACKGROUND: Severe obstructive sleep apnea (OSA) is an independent risk factor for perioperative complications. Clinical scores such as Snoring, Tiredness, Observed apnea, high blood Pressure, Body Mass Index (BMI) higher than 35 kg m-2, Age older than 50 years, Neck circumference larger than 40 cm, and male gender (STOP-Bang), perioperative sleep apnea prediction (P-SAP), and OSA50 have been proposed for detecting OSA. We recently proposed a new score based on morphological metrics only, the DES-OSA score. This study compared the DES-OSA score to the three other ones with regard to their ability to detect OSA. Obese patients are particularly at risk of OSA. METHODS: Following informed consent and institutional review board (IRB) approval, 1584 consecutive adults were. Should the STOP-Bang be indicative of increased risk of severe OSA, the patient was referred to complementary polysomnography (PSG). Eventual already existing recent PSG data were also collected. The abilities of the four scores to predict OSA severity were compared using sensitivity, specificity, Cohen's kappa coefficient (CKC), and area under ROC curve (AUROC) analysis. RESULTS: PSG was performed in 150 patients. For detecting severe OSA, OSA50 had the highest sensitivity [value (95 % CI) 0.98 (0.90-1)]. STOP-Bang was significantly less sensitive than P-SAP and OSA50. In that respect, DES-OSA was significantly more specific than the three other ones [0.75 (0.65-0.83)]. The AUROC of DES-OSA was significantly the largest [0.9 (0.84-0.95)]. The highest CKC at detecting severe OSA was 0.62 (0.49-0.74) for DES-OSA. Similar results were obtained for moderate to severe OSA prediction. CONCLUSIONS: DES-OSA, which is the only exclusively morphological score available, appears to surpass the three other scores in their ability to predict moderate to severe and severe OSA, at least in our setting and in our screened population. CLINICAL TRIAL REGISTRATION: ClinicalTrial.gov NCT02051829. [less ▲]

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See detailInfluence of premedication with alprazolam on the occurrence of obstructive apneas
Deflandre, Eric; BONHOMME, Vincent ULiege; Courtois, Anne-Catherine et al

in Journal of Physiology and Pharmacology (2016), 67(4), 617-624

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See detailTHE IMPLEMENTATION OF REGIONAL ANAESTHESIA BLOCK ROOMS IN BELGIUM: A NATIONAL SURVEY
BINDELLE, Simon ULiege; LECOQ, Jean-Pierre ULiege; Sermeus, Luc et al

in Regional Anesthesia and Pain Medicine (2015, September), 40(5), 162

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See detailConsciousness and complexity during unresponsiveness induced by propofol, xenon, and ketamine
Sarasso, Simone; Boly, Mélanie; Napolitani, Martino et al

in Current Biology (2015), 25(23), 3099-3105

A common endpoint of general anesthetics is behavioral unresponsiveness [1], which is commonly associated with loss of consciousness. However, subjects can become disconnected from the environment while ... [more ▼]

A common endpoint of general anesthetics is behavioral unresponsiveness [1], which is commonly associated with loss of consciousness. However, subjects can become disconnected from the environment while still having conscious experiences, as demonstrated by sleep states associated with dreaming [2]. Among anesthetics, ketamine is remarkable [3] in that it induces profound unresponsiveness, but subjects often report ketamine dreams upon emergence from anesthesia [4-9]. Here, we aimed at assessing consciousness during anesthesia with propofol, xenon, and ketamine, independent of behavioral responsiveness. To do so, in 18 healthy volunteers, we measured the complexity of the cortical response to transcranial magnetic stimulation (TMS) - an approach that has proven helpful in assessing objectively the level of consciousness irrespective of sensory processing and motor responses [10]. In addition, upon emergence from anesthesia, we collected reports about conscious experiences during unresponsiveness. Both frontal and parietal TMS elicited a low-amplitude electroencephalographic (EEG) slow wave corresponding to a local pattern of cortical activation with low complexity during propofol anesthesia, a high-amplitude EEG slow wave corresponding to a global, stereotypical pattern of cortical activation with low complexity during xenon anesthesia, and a wakefulness-like, complex spatiotemporal activation pattern during ketamine anesthesia. Crucially, participants reported no conscious experience after emergence from propofol and xenon anesthesia, whereas after ketamine they reported long, vivid dreams unrelated to the external environment. These results are relevant because they suggest that brain complexity may be sensitive to the presence of disconnected consciousness in subjects who are considered unconscious based on behavioral responses. © 2015 Elsevier Ltd All rights reserved. [less ▲]

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See detailPosterior Cingulate Cortex-Related Co-Activation Patterns: A Resting State fMRI Study in Propofol-Induced Loss of Consciousness
Amico, Enrico ULiege; Gomez, Francisco; Di Perri, Carol ULiege et al

in PLoS ONE (2014), 9

Background: Recent studies have been shown that functional connectivity of cerebral areas is not a static phenomenon, but exhibits spontaneous fluctuations over time. There is evidence that fluctuating ... [more ▼]

Background: Recent studies have been shown that functional connectivity of cerebral areas is not a static phenomenon, but exhibits spontaneous fluctuations over time. There is evidence that fluctuating connectivity is an intrinsic phenomenon of brain dynamics that persists during anesthesia. Lately, point process analysis applied on functional data has revealed that much of the information regarding brain connectivity is contained in a fraction of critical time points of a resting state dataset. In the present study we want to extend this methodology for the investigation of resting state fMRI spatial pattern changes during propofol-induced modulation of consciousness, with the aim of extracting new insights on brain networks consciousness-dependent fluctuations. Methods: Resting-state fMRI volumes on 18 healthy subjects were acquired in four clinical states during propofol injection: wakefulness, sedation, unconsciousness, and recovery. The dataset was reduced to a spatio-temporal point process by selecting time points in the Posterior Cingulate Cortex (PCC) at which the signal is higher than a given threshold (i.e., BOLD intensity above 1 standard deviation). Spatial clustering on the PCC time frames extracted was then performed (number of clusters = 8), to obtain 8 different PCC co-activation patterns (CAPs) for each level of consciousness. Results: The current analysis shows that the core of the PCC-CAPs throughout consciousness modulation seems to be preserved. Nonetheless, this methodology enables to differentiate region-specific propofol-induced reductions in PCC-CAPs, some of them already present in the functional connectivity literature (e.g., disconnections of the prefrontal cortex, thalamus, auditory cortex), some others new (e.g., reduced co-activation in motor cortex and visual area). Conclusion: In conclusion, our results indicate that the employed methodology can help in improving and refining the characterization of local functional changes in the brain associated to propofol-induced modulation of consciousness. [less ▲]

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See detailQuelle est la place de l'humain au sein des recommandations, des concertations oncologiques multidisciplinaires et du projet thérapeutique
BARTHELEMY, Nicole ULiege; BOGA, Deniz ULiege; PRINCEN, Fabienne ULiege et al

in Revue Médicale de Liège (2014), 69(Supp 1), 9-12

Le patient atteint de cancer bénéficie à l’heure actuelle d’une médecine très technique, de plus en plus ciblée et individualisée. Et l’Homme dans tout cela ? Divers outils ont été développés afin d’aider ... [more ▼]

Le patient atteint de cancer bénéficie à l’heure actuelle d’une médecine très technique, de plus en plus ciblée et individualisée. Et l’Homme dans tout cela ? Divers outils ont été développés afin d’aider les médecins et l’ensemble des soignants à concilier la médecine contemporaine et les droits fondamentaux du patient. Parmi ceux-ci, on trouve les Concertations Oncologiques Multidisciplinaires (COM) ainsi que les recommandations de traitement publiées par les socié - tés scientifiques nationales ou internationales. La prise en charge des patients doit être interdisciplinaire et basée sur une médecine factuelle. Ce processus de prise de décisions parta - gée doit, au final, être en accord avec les souhaits du patient. Cette approche doit lui permettre de conserver son autonomie et d’être l’acteur principal dans les prises de décision. [less ▲]

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See detailHow electroencephalography serves the anesthesiologist.
Marchant, Nicolas ULiege; Sanders, Robert; Sleigh, Jamie et al

in Clinical EEG and Neuroscience (2014), 45(1), 22-32

Major clinical endpoints of general anesthesia, such as the alteration of consciousness, are achieved through effects of anesthetic agents on the central nervous system, and, more precisely, on the brain ... [more ▼]

Major clinical endpoints of general anesthesia, such as the alteration of consciousness, are achieved through effects of anesthetic agents on the central nervous system, and, more precisely, on the brain. Historically, clinicians and researchers have always been interested in quantifying and characterizing those effects through recordings of surface brain electrical activity, namely electroencephalography (EEG). Over decades of research, the complex signal has been dissected to extract its core substance, with significant advances in the interpretation of the information it may contain. Methodological, engineering, statistical, mathematical, and computer progress now furnishes advanced tools that not only allow quantification of the effects of anesthesia, but also shed light on some aspects of anesthetic mechanisms. In this article, we will review how advanced EEG serves the anesthesiologist in that respect, but will not review other intraoperative utilities that have no direct relationship with consciousness, such as monitoring of brain and spinal cord integrity. We will start with a reminder of anesthestic effects on raw EEG and its time and frequency domain components, as well as a summary of the EEG analysis techniques of use for the anesthesiologist. This will introduce the description of the use of EEG to assess the depth of the hypnotic and anti-nociceptive components of anesthesia, and its clinical utility. The last part will describe the use of EEG for the understanding of mechanisms of anesthesia-induced alteration of consciousness. We will see how, eventually in association with transcranial magnetic stimulation, it allows exploring functional cerebral networks during anesthesia. We will also see how EEG recordings during anesthesia, and their sophisticated analysis, may help corroborate current theories of mental content generation. [less ▲]

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See detailThalamus, Brainstem and Salience Network Connectivity Changes During Propofol-Induced Sedation and Unconsciousness
Guldenmund, Justus Pieter ULiege; Demertzi, Athina ULiege; BOVEROUX, Pierre ULiege et al

in Brain Connectivity (2013), 3

In this functional magnetic resonance imaging study, we examined the effect of mild propofol sedation and propofol-induced unconsciousness on resting state brain connectivity, using graph analysis based ... [more ▼]

In this functional magnetic resonance imaging study, we examined the effect of mild propofol sedation and propofol-induced unconsciousness on resting state brain connectivity, using graph analysis based on independent component analysis and a classical seed-based analysis. Contrary to previous propofol research, which mainly emphasized the importance of connectivity in the default mode network (DMN) and external control network (ECN), we focused on the salience network, thalamus, and brainstem. The importance of these brain regions in brain arousal and organization merits a more detailed examination of their connectivity response to propofol. We found that the salience network disintegrated during propofol-induced unconsciousness. The thalamus decreased connectivity with the DMN, ECN, and salience network, while increasing connectivity with sensorimotor and auditory/insular cortices. Brainstem regions disconnected from the DMN with unconsciousness, while the pontine tegmental area increased connectivity with the insulae during mild sedation. These findings illustrate that loss of consciousness is associated with a wide variety of decreases and increases of both cortical and subcortical connectivity. It furthermore stresses the necessity of also examining resting state connectivity in networks representing arousal, not only those associated with awareness. [less ▲]

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