References of "Gosseries, Olivia"
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See detailDisorders of Consciousness
Bodart, Olivier ULg; Thibaut, Aurore ULg; Laureys, Steven ULg et al

in Citerio, G.; Smith, M.; Kofke, A. (Eds.) Oxford Textbook of neurocritical care (in press)

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See detailControlled clinical trial of repeated left prefrontal transcranial direct current stimulation in patients with chronic minimally conscious state
Martial, Charlotte ULg; Thibaut, Aurore ULg; Wannez, Sarah ULg et al

Poster (2015, June)

A recent study showed that single-session anodal transcranial direct current stimulation (tDCS) applied to the left dorsolateral prefrontal cortex (LDLPF) transiently improves consciousness in 43% of ... [more ▼]

A recent study showed that single-session anodal transcranial direct current stimulation (tDCS) applied to the left dorsolateral prefrontal cortex (LDLPF) transiently improves consciousness in 43% of patients in minimally conscious state (MCS) (Thibaut et al., 2014). We here test the potential effects and safety of repeated tDCS in severely brain-damaged patients with MCS. In this double-blind cross-over sham-controlled experimental design, we delivered two sessions of repeated (5 days of stimulation) tDCS, either anodal or sham in a randomized order. We stimulated the LDLPF cortex during twenty minutes in 20 MCS patients (12 men, aged 48±16 years, time since onset 78±95 months, 12 post-traumatic). Consciousness was assessed by the French adaptation of the Coma Recovery Scale Revised (CRS-R; Schnakers et al., 2008) before and after each stimulation. A treatment effect was observed for the comparison between CRS-R total scores at baseline and after 5 days of real tDCS (p<0.01). Behaviorally, 10/20 patients showed a tDCS-related improvement; 5 patients responded after the first stimulation and 5 other patients responded after 2, 3 or 4 days of stimulation. No side effect (e.g. epilepsy) was reported. Our results demonstrate that repeated (5 days) anodal LDLPF tDCS is safe and might improve signs of consciousness in about half of patients in MCS. It is important to note that the first session is not predictive for a future positive effect of the efficacy of the non-invasive electrical stimulation. [less ▲]

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See detailCortical responses to transcranial magnetic stimulation during Non-Rapid Eye Movement Sleep
Gosseries, Olivia ULg; Jaakko, Nieminen; Siclari, Francesca et al

Poster (2015, March)

Transcranial magnetic stimulation coupled to high-density electroencephalography (TMS-EEG) allows for directly and non-invasively stimulating the brain and recording the subsequent cortical response ... [more ▼]

Transcranial magnetic stimulation coupled to high-density electroencephalography (TMS-EEG) allows for directly and non-invasively stimulating the brain and recording the subsequent cortical response. Previous TMS-EEG studies have shown clear-cut differences between conscious and unconscious conditions. When subjects are unconscious, as in non-rapid eye movement (NREM) sleep early in the night (stage N3), anesthesia or coma, TMS typically triggers a stereotypical and local slow-wave response. When they are conscious, as in normal wakefulness and rapid eye movement sleep (REM) sleep, brain responses to TMS are long-lasting, widespread, complex, and differentiated. In this study, we performed TMS-EEG during NREM sleep in stage 2 (N2) and N3 on 7 healthy participants. Brain activity was recorded using a 60-channel TMS-compatible EEG and single-pulse TMS was applied (up to 285 pulses per session) on the superior parietal cortex. After each TMS session (5 to 15 sessions per night), subjects were awakened to ask for a dream report. TMS-EEG responses were analyzed using the global mean field amplitude (GMFA), the perturbational complexity index (PCI), as well as time-frequency measures. Our results show that the TMS-EEG response during N3 is larger and slower than during N2 sleep. The GMFA is higher and PCI is lower in N3 as compared to N2 sleep. Moreover, N3 recordings showed activation at lower frequency bands after TMS as compared to N2 sleep. Additionally, TMS-EEG responses vary depending on whether subjects do or do not report a dream. TMS-EEG might provide valuable information for characterizing neurophysiological fluctuations and levels of consciousness within NREM sleep. [less ▲]

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See detailChanges in cerebral metabolism in patients with a minimally conscious state responding to zolpidem.
Chatelle, Camille ULg; Thibaut, Aurore ULg; Gosseries, Olivia ULg et al

in Frontiers in Neuroscience (2014)

BACKGROUND: Zolpidem, a short-acting non-benzodiazepine GABA agonist hypnotic, has been shown to induce paradoxical responses in some patients with disorders of consciousness (DOC), leading to recovery of ... [more ▼]

BACKGROUND: Zolpidem, a short-acting non-benzodiazepine GABA agonist hypnotic, has been shown to induce paradoxical responses in some patients with disorders of consciousness (DOC), leading to recovery of arousal and cognitive abilities. We here assessed zolpidem-induced changes in regional brain metabolism in three patients with known zolpidem response in chronic post-anoxic minimally conscious state (MCS). METHODS: [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) and standardized clinical assessments using the Coma Recovery Scale-Revised were performed after administration of 10 mg zolpidem or placebo in a randomized double blind 2-day protocol. PET data preprocessing and comparison with a healthy age-matched control group were performed using statistical parametric mapping (SPM8). RESULTS: Behaviorally, all patients recovered functional communication after administration of zolpidem (i.e., emergence from the MCS). FDG-PET showed increased metabolism in dorsolateral prefrontal and mesiofrontal cortices after zolpidem but not after placebo administration. CONCLUSION: Our data show a metabolic activation of prefrontal areas, corroborating the proposed mesocircuit hypothesis to explain the paradoxical effect of zolpidem observed in some patients with DOC. It also suggests the key role of the prefrontal cortices in the recovery of functional communication and object use in hypoxic patients with chronic MCS. [less ▲]

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See detailTranscranial magnetic stimulation combined with high density EEG in altered states of consciousness
Napolitani, M.; Bodart, Olivier ULg; Canali, P. et al

in Brain injury : [BI] (2014), 28(9), 1180-1189

Background: This review discusses the advantages of transcranial magnetic stimulation combined with high-density electroencephalography (TMS-hdEEG) over other current techniques of brain imaging. Methods ... [more ▼]

Background: This review discusses the advantages of transcranial magnetic stimulation combined with high-density electroencephalography (TMS-hdEEG) over other current techniques of brain imaging. Methods and results: Its application was reviewed, focusing particularly on disorders of consciousness, in the perspective of recent theories of consciousness. Assessment of non-communicative patients with disorders of consciousness remains a clinical challenge and objective measures of the level of consciousness are still needed. Current theories suggest that a key requirement for consciousness is the brain’s capacity to rapidly integrate information across different specialized cortical areas. TMS-EEG allows the stimulation of any given cortical area and the recording of the immediate electrical cortical response. This technique has recently been successfully employed to measure changes in brain complexity under physiological, pharmacological and pathological conditions. Conclusions: This suggests that TMS-EEG is a reliable tool to discriminate between conscious and unconscious patients at the single subject level. Future works are needed to validate and implement this technique as a clinical tool. [less ▲]

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See detailThe Glasgow Coma Scale: time for critical reappraisal?
Laureys, Steven ULg; Bodart, Olivier ULg; Gosseries, Olivia ULg

in Lancet Neurology (2014), Vol 13

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See detailVolitional electromyographic responses in disorders of consciousness
Habbal, Dina; Gosseries, Olivia ULg; Noirhomme, Quentin ULg et al

in Brain Injury (2014)

The aim of the study was to validate the use of electromyography (EMG) for detecting responses to command in patients in vegetative state/unresponsive wakefulness syndrome (VS/UWS) or in minimally ... [more ▼]

The aim of the study was to validate the use of electromyography (EMG) for detecting responses to command in patients in vegetative state/unresponsive wakefulness syndrome (VS/UWS) or in minimally conscious state (MCS). Methods: Thirty-eight patients were included in the study (23 traumatic, 25 patients >1 year post-onset), 10 diagnosed as being in VS/UWS, eight in MCS- (no response to command) and 20 in MCS+ (response to command). Eighteen age-matched controls participated in the experiment. The paradigm consisted of three commands (i.e. 'Move your hands', 'Move your legs' and 'Clench your teeth') and one control sentence (i.e. 'It is a sunny day') presented in random order. Each auditory stimulus was repeated 4-times within one block with a stimulus-onset asynchrony of 30 seconds. Results: Post-hoc analyses with Bonferroni correction revealed that EMG activity was higher solely for the target command in one patient in permanent VS/UWS and in three patients in MCS+. Conclusion: The use of EMG could help clinicians to detect conscious patients who do not show any volitional response during standard behavioural assessments. However, further investigations should determine the sensitivity of EMG as compared to neuroimaging and electrophysiological assessments. [less ▲]

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See detailDiagnostic precision of PET imaging and functional MRI in disorders of consciousness: a clinical validation study
Stender, Johan; Gosseries, Olivia ULg; Bruno, Marie-Aurélie ULg et al

in Lancet Neurology (2014)

Background: Bedside clinical examinations can have high rates of misdiagnosis of unresponsive wakefulness syndrome (vegetative state) or minimally conscious state. The diagnostic and prognostic usefulness ... [more ▼]

Background: Bedside clinical examinations can have high rates of misdiagnosis of unresponsive wakefulness syndrome (vegetative state) or minimally conscious state. The diagnostic and prognostic usefulness of neuroimaging-based approaches has not been established in a clinical setting. We did a validation study of two neuroimaging-based diagnostic methods: PET imaging and functional MRI (fMRI). Methods: For this clinical validation study, we included patients referred to the University Hospital of Liège, Belgium, between January, 2008, and June, 2012, who were diagnosed by our unit with unresponsive wakefulness syndrome, locked-in syndrome, or minimally conscious state with traumatic or non-traumatic causes. We did repeated standardised clinical assessments with the Coma Recovery Scale—Revised (CRS—R), cerebral 18F-fluorodeoxyglucose (FDG) PET, and fMRI during mental activation tasks. We calculated the diagnostic accuracy of both imaging methods with CRS—R diagnosis as reference. We assessed outcome after 12 months with the Glasgow Outcome Scale—Extended. Findings: We included 41 patients with unresponsive wakefulness syndrome, four with locked-in syndrome, and 81 in a minimally conscious state (48=traumatic, 78=non-traumatic; 110=chronic, 16=subacute). 18F-FDG PET had high sensitivity for identification of patients in a minimally conscious state (93%, 95% CI 85—98) and high congruence (85%, 77—90) with behavioural CRS—R scores. The active fMRI method was less sensitive at diagnosis of a minimally conscious state (45%, 30—61) and had lower overall congruence with behavioural scores (63%, 51—73) than PET imaging. 18F-FDG PET correctly predicted outcome in 75 of 102 patients (74%, 64—81), and fMRI in 36 of 65 patients (56%, 43—67). 13 of 42 (32%) of the behaviourally unresponsive patients (ie, diagnosed as unresponsive with CRS—R) showed brain activity compatible with (minimal) consciousness (ie, activity associated with consciousness, but diminished compared with fully conscious individuals) on at least one neuroimaging test; 69% of these (9 of 13) patients subsequently recovered consciousness. Interpretation: Cerebral 18F-FDG PET could be used to complement bedside examinations and predict long-term recovery of patients with unresponsive wakefulness syndrome. Active fMRI might also be useful for differential diagnosis, but seems to be less accurate. Funding: The Belgian National Funds for Scientific Research (FNRS), Fonds Léon Fredericq, the European Commission, the James McDonnell Foundation, the Mind Science Foundation, the French Speaking Community Concerted Research Action, the University of Copenhagen, and the University of Liège. [less ▲]

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See detailEffect of zolpidem in chronic disorders of consciousness: a prospective open-label study.
Thonnard, Marie ULg; Gosseries, Olivia ULg; Demertzi, Athina ULg et al

in Functional Neurology (2014)

Zolpidem has been reported as an "awakening drug" in some patients with disorders of consciousness (DOC). We here present the results of a prospective openlabel study in chronic DOC patients. Sixty ... [more ▼]

Zolpidem has been reported as an "awakening drug" in some patients with disorders of consciousness (DOC). We here present the results of a prospective openlabel study in chronic DOC patients. Sixty patients (35±15 years; 18 females; mean time since insult ± SD: 4±5.5 years; 31 with traumatic etiology) with a diagnosis of vegetative state/unresponsive wakefulness syndrome (n=28) or minimally conscious state (n=32) were behaviorally assessed using the Coma Recovery Scale-Revised (CRS-R) before and one hour after administration of 10 mg of zolpidem. At the group level, the diagnosis did not change after intake of zolpidem (p=0.10) and CRS-R total scores decreased (p=0.01). Twelve patients (20%) showed improved behaviors and/or CRS-R total scores after zolpidem administration but in only one patient was the diagnosis after zolpidem intake found to show a significant improvement (functional object use), which suggested a change of diagnosis. However, in this patient, a double-blind placebo-controlled trial was performed in order to better specify the effects of zolpidem, but the patient, on this trial, failed to show any clinical improvements. The present open-label study therefore failed to show any clinically significant improvement (i.e., change of Effect of zolpidem in chronic disorders of consciousness: a prospective open-label study diagnosis) in any of the 60 studied chronic DOC patients. [less ▲]

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See detailAssessing consciousness in coma and related states using transcranial magnetic stimulation combined with electroencephalography.
Gosseries, Olivia ULg; Thibaut, Aurore ULg; Boly, Mélanie ULg et al

in Annales Françaises d'Anesthésie et de Réanimation (2014)

Thanks to advances in medical care, an increased number of patients recover from coma. However, some remain in vegetative/unresponsive wakefulness syndrome or in a minimally conscious state. Detection of ... [more ▼]

Thanks to advances in medical care, an increased number of patients recover from coma. However, some remain in vegetative/unresponsive wakefulness syndrome or in a minimally conscious state. Detection of awareness in severely brain-injured patients is challenging because it relies on behavioral assessments, which can be affected by motor, sensory and cognitive impairments of the patients. Other means of evaluation are needed to improve the accuracy of the diagnosis in this challenging population. We will here review the different altered states of consciousness occurring after severe brain damage, and explain the difficulties associated with behavioral assessment of consciousness. We will then describe a non-invasive technique, transcranial magnetic stimulation combined with high-density electroencephalography (TMS-EEG), which has allowed us to detect the presence or absence of consciousness in different physiological, pathological and pharmacological states. Some potential underlying mechanisms of the loss of consciousness will then be discussed. In conclusion, TMS-EEG is highly promising in identifying markers of consciousness at the individual level and might be of great value for clinicians in the assessment of consciousness. [less ▲]

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See detailQuantifying cortical EEG responses to TMS in (un)consciousness
Sarasso, S; Rosanova, M; Casali, A.G et al

in Clinical EEG and Neuroscience : Official Journal of the EEG and Clinical Neuroscience Society (ENCS) (2014)

We normally assess another individual's level of consciousness based on her or his ability to interact with the surrounding environment and communicate. Usually, if we observe purposeful behavior ... [more ▼]

We normally assess another individual's level of consciousness based on her or his ability to interact with the surrounding environment and communicate. Usually, if we observe purposeful behavior, appropriate responses to sensory inputs, and, above all, appropriate answers to questions, we can be reasonably sure that the person is conscious. However, we know that consciousness can be entirely within the brain, even in the absence of any interaction with the external world; this happens almost every night, while we dream. Yet, to this day, we lack an objective, dependable measure of the level of consciousness that is independent of processing sensory inputs and producing appropriate motor outputs. Theoretically, consciousness is thought to require the joint presence of functional integration and functional differentiation, otherwise defined as brain complexity. Here we review a series of recent studies in which Transcranial Magnetic Stimulation combined with electroencephalography (TMS/EEG) has been employed to quantify brain complexity in wakefulness and during physiological (sleep), pharmacological (anesthesia) and pathological (brain injury) loss of consciousness. These studies invariably show that the complexity of the cortical response to TMS collapses when consciousness is lost during deep sleep, anesthesia and vegetative state following severe brain injury, while it recovers when consciousness resurges in wakefulness, during dreaming, in the minimally conscious state or locked-in syndrome. The present paper will also focus on how this approach may contribute to unveiling the pathophysiology of disorders of consciousness affecting brain-injured patients. Finally, we will underline some crucial methodological aspects concerning TMS/EEG measurements of brain complexity. [less ▲]

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See detailDIRECTED INFORMATION TRANSFER IN SCALP ELECTROENCEPHALOGRAPHIC RECORDINGS: INSIGHTS ON DISORDERS OF CONSCIOUSNESS
Marinazzo, Daniele; Gosseries, Olivia ULg; Boly, Mélanie ULg et al

in Clinical EEG and Neuroscience : Official Journal of the EEG and Clinical Neuroscience Society (ENCS) (2014)

Introduction: The neural mechanisms underlying electrophysiological changes observed in patients with disorders of consciousness following a coma remain poorly understood. The aim of this article is to ... [more ▼]

Introduction: The neural mechanisms underlying electrophysiological changes observed in patients with disorders of consciousness following a coma remain poorly understood. The aim of this article is to investigate the mechanisms underlying the differences in spontaneous electroencephalography between patients in vegetative/unresponsive wakefulness syndrome, minimally conscious state, emergence of the minimally conscious state and age-matched healthy control subjects. <br />Methods: Forty recording of spontaneous scalp electroencephalography were performed in 27 patients who were comatose on admission, and on healthy controls. Multivariate Granger Causality and Transfer Entropy were applied on the data. <br />Results: Distinctive patterns of putative bottlenecks of information were associated to each conscious state. Healthy controls are characterized by a greater amount of synergetic contributions from duplets of variables. <br />Conclusion: A novel set of measures was tested to get a novel insight on the pattern of information transfer in a network of scalp electrodes in patients with disorders of consciousness. [less ▲]

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See detailFunctional neuroanatomy of disorders of consciousness
Di Perri, Carol; Stender, Johan; Laureys, Steven ULg et al

in CAVANNA, Andrea (Ed.) Epilepsy and behavior Alteration of Counsciousness in Epilepsy (2014)

Our understanding of the mechanisms of loss and recovery of consciousness, following severe brain injury or during anesthesia, is changing rapidly. Recent neuroimaging studies have shown that patients ... [more ▼]

Our understanding of the mechanisms of loss and recovery of consciousness, following severe brain injury or during anesthesia, is changing rapidly. Recent neuroimaging studies have shown that patients with chronic disorders of consciousness and subjects undergoing general anesthesia present a complex dysfunctionality in the architecture of brain connectivity. At present, the global hallmark of impaired consciousness appears to be amultifaceted dysfunctional connectivity pattern with both within-network loss of connectivity in awidespread frontoparietal network and between-network hyperconnectivity involving other regions such as the insula and ventral tegmental area. Despite ongoing efforts, the mechanisms underlying the emergence of consciousness after severe brain injury are not thoroughly understood. Important questions remain unanswered:What triggers the connectivity impairment leading to disorders of consciousness? Why do some patients recover from coma, while others with apparently similar brain injuries do not? Understanding these mechanisms could lead to a better comprehension of brain function and, hopefully, lead to new therapeutic strategies in this challenging patient population. [less ▲]

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See detailNeuroimaging in Disorders of Consciousness
Bodart, Olivier ULg; Charland-Verville, Vanessa ULg; Laureys, Steven ULg et al

in Filippi, M. (Ed.) Oxford Textbook of Clinical Neurology (2014)

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See detailAmantadine, Apomorphine and Zolpidem in the Treatment of Disorders of Consciousness
Gosseries, Olivia ULg; Charland-Verville, Vanessa ULg; Thonnard, Marie ULg et al

in Current Pharmaceutical Design (2014), 20

Survivors of severe brain injuries may end up in a state of 'wakeful unresponsiveness' or in a minimally conscious state. Pharmacological treatments of patients with disorders of consciousness aim to ... [more ▼]

Survivors of severe brain injuries may end up in a state of 'wakeful unresponsiveness' or in a minimally conscious state. Pharmacological treatments of patients with disorders of consciousness aim to improve arousal levels and recovery of consciousness. We here provide a systematic overview of the therapeutic effects of amantadine, apomorphine and zolpidem in patients recovering from coma. Evidence from clinical trials using these commonly prescribed pharmacological agents suggests positive changes in the neurological status in patients, leading sometimes to dramatic improvements. These findings are discussed in the context of current hypotheses of these agents' therapeutic mechanisms on cerebral function. In order to enhance our understanding of the underlying pathophysiological mechanisms of these drugs, we suggest combining sensitive and specific behavioral tools with neuroimaging and electrophysiological measures in large randomized, double-blind, placebo-controlled experimental designs. We conclude that the pharmacokinetics and pharmacodynamics of amantadine, apomorphine and zolpidem need further exploration to determine which treatment would provide a better neurological outcome regarding the patient's etiology, diagnosis, time since injury and overall condition. [less ▲]

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See detailCommon resting brain dynamics indicate a possible mechanism underlying zolpidem response in severe brain injury
Williams, Shawniqua; Conte, Mary; Goldfine, Andrew et al

in eLife (2013)

Zolpidem produces paradoxical recovery of speech, cognitive and motor functions in select subjects with severe brain injury but underlying mechanisms remain unknown. In three diverse patients with known ... [more ▼]

Zolpidem produces paradoxical recovery of speech, cognitive and motor functions in select subjects with severe brain injury but underlying mechanisms remain unknown. In three diverse patients with known zolpidem responses we identify a distinctive pattern of EEG dynamics that suggests a mechanistic model. In the absence of zolpidem, all subjects show a strong low frequency oscillatory peak ∼6–10 Hz in the EEG power spectrum most prominent over frontocentral regions and with high coherence (∼0.7–0.8) within and between hemispheres. Zolpidem administration sharply reduces EEG power and coherence at these low frequencies. The ∼6–10 Hz activity is proposed to arise from intrinsic membrane properties of pyramidal neurons that are passively entrained across the cortex by locally-generated spontaneous activity. Activation by zolpidem is proposed to arise from a combination of initial direct drug effects on cortical, striatal, and thalamic populations and further activation of underactive brain regions induced by restoration of cognitively-mediated behaviors. [less ▲]

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See detailDynamic change of global and local information processing in Propofol-induced loss and recovery of consciousness
Monti, Martin; Lutkenoff, Evan; Rubinov, Mikail et al

in PLoS Computational Biology (2013), 9

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See detailChanges in Effective Connectivity by Propofol Sedation
Gomez Jaramillo, Francisco Albeiro ULg; Phillips, Christophe ULg; Soddu, Andrea ULg et al

in PLoS ONE (2013), 8(8), 71370

Mechanisms of propofol-induced loss of consciousness remain poorly understood. Recent fMRI studies have shown decreases in functional connectivity during unconsciousness induced by this anesthetic agent ... [more ▼]

Mechanisms of propofol-induced loss of consciousness remain poorly understood. Recent fMRI studies have shown decreases in functional connectivity during unconsciousness induced by this anesthetic agent. Functional connectivity does not provide information of directional changes in the dynamics observed during unconsciousness. The aim of the present study was to investigate, in healthy humans during an auditory task, the changes in effective connectivity resulting from propofol induced loss of consciousness. We used Dynamic Causal Modeling for fMRI (fMRI-DCM) to assess how causal connectivity is influenced by the anesthetic agent in the auditory system. Our results suggest that the dynamic observed in the auditory system during unconsciousness induced by propofol, can result in a mixture of two effects: a local inhibitory connectivity increase and a decrease in the effective connectivity in sensory cortices. [less ▲]

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