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Staquet C, Vanhaudenhuyse A, Kandeepan S, Sanders RD, Ribeiro de Paula D, Brichant JF, Laureys S, Bonhomme V, Soddu A. Changes in Intrinsic Connectivity Networks Topology Across Levels of Dexmedetomidine-Induced Alteration of Consciousness. Anesth Analg 2024:00000539-990000000-00713. [PMID: 38289856 DOI: 10.1213/ane.0000000000006799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
BACKGROUND Human consciousness is generally thought to emerge from the activity of intrinsic connectivity networks (resting-state networks [RSNs]) of the brain, which have topological characteristics including, among others, graph strength and efficiency. So far, most functional brain imaging studies in anesthetized subjects have compared wakefulness and unresponsiveness, a state considered as corresponding to unconsciousness. Sedation and general anesthesia not only produce unconsciousness but also phenomenological states of preserved mental content and perception of the environment (connected consciousness), and preserved mental content but no perception of the environment (disconnected consciousness). Unresponsiveness may be seen during unconsciousness, but also during disconnectedness. Deep dexmedetomidine sedation is frequently a state of disconnected consciousness. In this study, we were interested in characterizing the RSN topology changes across 4 different and steady-state levels of dexmedetomidine-induced alteration of consciousness, namely baseline (Awake, drug-free state), Mild sedation (drowsy, still responding), Deep sedation (unresponsive), and Recovery, with a focus on changes occurring between a connected consciousness state and an unresponsiveness state. METHODS A functional magnetic resonance imaging database acquired in 14 healthy volunteers receiving dexmedetomidine sedation was analyzed using a method combining independent component analysis and graph theory, specifically looking at changes in connectivity strength and efficiency occurring during the 4 above-mentioned dexmedetomidine-induced altered consciousness states. RESULTS Dexmedetomidine sedation preserves RSN architecture. Unresponsiveness during dexmedetomidine sedation is mainly characterized by a between-networks graph strength alteration and within-network efficiency alteration of lower-order sensory RSNs, while graph strength and efficiency in higher-order RSNs are relatively preserved. CONCLUSIONS The differential dexmedetomidine-induced RSN topological changes evidenced in this study may be the signature of inadequate processing of sensory information by lower-order RSNs, and of altered communication between lower-order and higher-order networks, while the latter remain functional. If replicated in an experimental paradigm distinguishing, in unresponsive subjects, disconnected consciousness from unconsciousness, such changes would sustain the hypothesis that disconnected consciousness arises from altered information handling by lower-order sensory networks and altered communication between lower-order and higher-order networks, while the preservation of higher-order networks functioning allows for an internally generated mental content (or dream).
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Affiliation(s)
- Cecile Staquet
- From the Anesthesia and Perioperative Neuroscience Laboratory, GIGA-Consciousness, Liege University, Liege, Belgium
- Department of Anesthesia and Intensive Care Medicine, Liege University Hospital, Liege, Belgium
- GIGA-In Vivo Imaging (CRC) Platform, GIGA-Research, Liege University, Liege, Belgium
- Interdisciplinary Center of Algology, Liege University Hospital, Liege, Belgium
| | - Audrey Vanhaudenhuyse
- Interdisciplinary Center of Algology, Liege University Hospital, Liege, Belgium
- Sensation & Perception Research Group, GIGA-Consciousness, Liege University, Liege, Belgium
| | - Sivayini Kandeepan
- Department of Physics and Astronomy, Western Institute for Neuroscience, University of Western Ontario, London, Ontario, Canada
- Department of Physics, Faculty of Applied Sciences, University of Sri Jayewardenepura, Nugegoda, Sri Lanka
| | - Robert D Sanders
- University of Sydney, Sydney, New South Wales, Australia
- Department of Anaesthetics, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
- Institute of Academic Surgery, Sydney, New South Wales, Australia
| | - Demetrius Ribeiro de Paula
- Donders Institute for Brain Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Jean François Brichant
- Department of Anesthesia and Intensive Care Medicine, Liege University Hospital, Liege, Belgium
| | - Steven Laureys
- Coma Science Group, GIGA-Consciousness, Liege University, Liege, Belgium; and
- Centre du Cerveau, Liege University Hospital, Liege, Belgium
| | - Vincent Bonhomme
- From the Anesthesia and Perioperative Neuroscience Laboratory, GIGA-Consciousness, Liege University, Liege, Belgium
- Department of Anesthesia and Intensive Care Medicine, Liege University Hospital, Liege, Belgium
- Institute of Academic Surgery, Sydney, New South Wales, Australia
- Donders Institute for Brain Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Andrea Soddu
- Department of Physics and Astronomy, Western Institute for Neuroscience, University of Western Ontario, London, Ontario, Canada
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