Changes in Resting Neural Connectivity during Propofol Sedation

Stamatakis, Emmanuel A.; Adapa, R.; Absalom, Anthony; Menon, David

doi:10.1371/journal.pone.0014224

Cited by 177 publications

(169 citation statements)

References 69 publications

(111 reference statements)

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“…Evidence for reduced coupling between posterior, parietal, and frontal cortices was reported in recent studies during deep NREM sleep (Horovitz et al, 2009;Sämann et al, 2011) and anesthesia (Boveroux et al, 2010;Schrouff et al, 2011). Reorganized connectivity of posterior nodes, such as PCC, has been reported already for moderate levels of propofol (Stamatakis et al, 2010). …”

Section: Effects Of Pi-loc On Subcortical and Cortical Functional Conmentioning

confidence: 86%

“…While early fMRI studies of BOLD signal fluctuations across levels of consciousness reported persistent intrinsic activity and relatively preserved spatial organization during light sleep and sedation (Greicius et al, 2008;Horovitz et al, 2008;LarsonPrior et al, 2009), recent studies point to a state-dependent modulation: during propofol-anesthesia, a linear association between functional connectivity of frontoparietal networks and levels of consciousness (Boveroux et al, 2010), a reorganization of key nodes of the default mode network (Stamatakis et al, 2010), and decreased subcortical-cortical connectivity have been reported (Mhuircheartaigh et al, 2010). State-dependent changes in functional connectivity have also been observed during deep NREM sleep (Horovitz et al, 2009;Sämann et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

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Spatiotemporal Reconfiguration of Large-Scale Brain Functional Networks during Propofol-Induced Loss of Consciousness

et al. 2012

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Applying graph theoretical analysis of spontaneous BOLD fluctuations in functional magnetic resonance imaging (fMRI), we investigated whole-brain functional connectivity of 11 healthy volunteers during wakefulness and propofol-induced loss of consciousness (PI-LOC). After extraction of regional fMRI time series from 110 cortical and subcortical regions, we applied a maximum overlap discrete wavelet transformation and investigated changes in the brain's intrinsic spatiotemporal organization. During PI-LOC, we observed a breakdown of subcortico-cortical and corticocortical connectivity. Decrease of connectivity was pronounced in thalamocortical connections, whereas no changes were found for connectivity within primary sensory cortices. Graph theoretical analyses revealed significant changes in the degree distribution and local organization metrics of brain functional networks during PI-LOC: compared with a random network, normalized clustering was significantly increased, as was small-worldness. Furthermore we observed a profound decline in long-range connections and a reduction in whole-brain spatiotemporal integration, supporting a topological reconfiguration during PI-LOC. Our findings shed light on the functional significance of intrinsic brain activity as measured by spontaneous BOLD signal fluctuations and help to understand propofol-induced loss of consciousness.

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Section: Effects Of Pi-loc On Subcortical and Cortical Functional Conmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Spatiotemporal Reconfiguration of Large-Scale Brain Functional Networks during Propofol-Induced Loss of Consciousness

et al. 2012

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“…Suppressed frontoparietal and thalamic activity appear to be a common finding in most anesthesia studies (Kaisti et al, 2002;Baars et al, 2003;Bonhomme et al, 2008;Mhuircheartaigh et al, 2010;Stamatakis et al, 2010;Schrouff et al, 2011;Tu et al, 2011). These changes have generally been interpreted directly as neural correlates for LOC.…”

Section: Discussionmentioning

confidence: 97%

“…A number of studies have now examined the connectivity effects associated with changing levels of consciousness (Imas et al, 2005;Massimini et al, 2005;Boveroux et al, 2010;Mhuircheartaigh et al, 2010;Stamatakis et al, 2010;Boly, 2011;Boly et al, 2011;Schrouff et al, 2011). It has been hypothesized that decreased frontal to parietal feedback is a likely correlate for the diminished consciousness associated with sleep (Massimini et al, 2005), brain injury , and anesthesia (Imas et al, 2005;Alkire et al, 2008;Ku et al, 2011).…”

Section: Discussionmentioning

confidence: 99%

“…Anesthesia is a tool for studying consciousness as it allows the level of consciousness to be directly manipulated (Beecher, 1947;Alkire et al, 2008;Stamatakis et al, 2010;Schrouff et al, 2011;. However, use of this tool requires overcoming the limitation that a drug-induced unconscious state is necessarily confounded by the presence of the drug used to induce unconsciousness (Tononi and Koch, 2008).…”

Section: Introductionmentioning

confidence: 99%

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Returning from Oblivion: Imaging the Neural Core of Consciousness

Långsjö

Alkire²,

Kaskinoro³

et al. 2012

J. Neurosci.

190

147

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One of the greatest challenges of modern neuroscience is to discover the neural mechanisms of consciousness and to explain how they produce the conscious state. We sought the underlying neural substrate of human consciousness by manipulating the level of consciousness in volunteers with anesthetic agents and visualizing the resultant changes in brain activity using regional cerebral blood flow imaging with positron emission tomography. Study design and methodology were chosen to dissociate the state-related changes in consciousness from the effects of the anesthetic drugs. We found the emergence of consciousness, as assessed with a motor response to a spoken command, to be associated with the activation of a core network involving subcortical and limbic regions that become functionally coupled with parts of frontal and inferior parietal cortices upon awakening from unconsciousness. The neural core of consciousness thus involves forebrain arousal acting to link motor intentions originating in posterior sensory integration regions with motor action control arising in more anterior brain regions. These findings reveal the clearest picture yet of the minimal neural correlates required for a conscious state to emerge.

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Mouth Closure and Airflow in Patients With Obstructive Sleep Apnea

Yang,

Huyett,

Wang

et al. 2024

JAMA Otolaryngol Head Neck Surg

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ImportanceMouth breathing is associated with increased airway resistance, pharyngeal collapsibility, and obstructive sleep apnea (OSA) severity. The common belief is that closing the mouth can mitigate the negative effects of mouth breathing during sleep. However, mouth breathing may serve as an essential route to bypassing obstruction along the nasal route (eg, the velopharynx).ObjectiveTo investigate the role of mouth breathing as an essential route in some patients with OSA and its association with upper airway anatomical factors.Design, Setting, and ParticipantsThis nonrandomized clinical trial included participants diagnosed with OSA who underwent drug-induced sleep endoscopy. Patients were stratified into 3 quantiles based on oral-breathing level (quantile 1: oral airflow &lt; 0.05 L/min; quantile 2: oral airflow 0.05-2.2 L/min; quantile 3: oral airflow &gt; 2.2 L/min).InterventionsClosing the mouth during sleep during alternating breaths by applying pressure to the mentum until teeth are in occlusion.Main Outcomes and MeasuresThe primary outcome was total inspiratory flow defined as the change in airflow in the transition from mouth relaxed to mouth closed, analyzed overall and by 3 oral-breathing quantiles. The association of velopharyngeal obstruction on the change in total inspiratory airflow was also investigated.ResultsOf 66 enrolled patients with OSA, 12 were excluded due to insufficient baseline airflow. The analytic cohort consisted of 54 patients (39 [72%] male; median [IQR] age, 55 [46-64] years; apnea-hypopnea index, 26.9 [17.6-39.9] events/h; and body mass index calculated as weight in kilograms divided by height in meters squared, 28.9 [27.1-31.6]). Mouth closure increased total inspiratory flow by 27.8 percentage points overall (β, 1.0 [95% CI, 0.4-1.9] L/min). However, outcomes varied based on the degree of baseline oral breathing. No association was found for 10 patients with near-zero mouth breathing (0.9 [95% CI, −0.2 to 2.1] L/min). Airflow improved with mouth closure in 32 patients with moderate levels of mouth breathing (2.0 [95% CI, 1.3-2.7] L/min), whereas it worsened in patients with high levels of mouth breathing (−1.9 [95% CI, −3.1 to −0.6] L/min). Velopharyngeal obstruction was associated with increased mouth breathing (0.6 [95% CI, 0.1-3.0] L/min) and reduced airflow with mouth closure (−1.9 [95% CI, −3.1 to −0.7] L/min).Conclusion and RelevanceAlthough mouth closure increased inspiratory airflow in the overall cohort of this nonrandomized clinical trial, the outcomes were heterogeneous. In patients who breathe primarily through their mouth during sleep and have velopharyngeal obstruction, airflow worsens with mouth closure. Hence, personalized approaches to treating mouth breathing should be considered.Trial RegistrationClinicalTrials.gov Identifier: NCT06547658

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Changes in Resting Neural Connectivity during Propofol Sedation

Cited by 177 publications

References 69 publications

Spatiotemporal Reconfiguration of Large-Scale Brain Functional Networks during Propofol-Induced Loss of Consciousness

Spatiotemporal Reconfiguration of Large-Scale Brain Functional Networks during Propofol-Induced Loss of Consciousness

Returning from Oblivion: Imaging the Neural Core of Consciousness

Mouth Closure and Airflow in Patients With Obstructive Sleep Apnea

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