Functional diversity of brain networks supports consciousness and verbal intelligence

Naçi, Lorina; Haugg, Amelie; MacDonald, Alex A.; Anello, Mimma; Houldin, Evan; Naqshbandi, Shakib; González-Lara, Laura E.; Arango, Miguel; Harle, Christopher; Cusack, Rhodri; Owen, Adrian M.

doi:10.1101/336859

Cited by 17 publications

(35 citation statements)

References 82 publications

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“…Although frontal-parietal connectivity did not reliably appear to decrease during general anesthesia, Naci et al recently demonstrated a number of complementary possibilities, including a disrupted frontal-parietal network or a maintained frontal-parietal connectivity that is functionally disconnected from sensory cortex. 48 Lastly, despite the outlined artifact-reduction and filtering strategies, artifactual contamination remains possible. Nonetheless, we have demonstrated the ability to acquire these neurophysiologic data in a pragmatic surgical setting.…”

Section: Discussionmentioning

confidence: 99%

Dynamic Cortical Connectivity during General Anesthesia in Surgical Patients

Vlisides

Zierau

et al. 2019

Anesthesiology

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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.

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Section: Discussionmentioning

confidence: 99%

Dynamic Cortical Connectivity during General Anesthesia in Surgical Patients

Vlisides

Zierau

et al. 2019

Anesthesiology

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“…The propofol data employed in this study have been published before (Luppi et al, 2019; Naci et al, 2018; Varley et al, 2020a). For clarity and consistency of reporting, where applicable we use the same wording as our previous study (Luppi et al, 2019).…”

Section: Methodsmentioning

confidence: 99%

A Synergistic Workspace for Human Consciousness Revealed by Integrated Information Decomposition

Ai¹,

Mediano

et al. 2020

Preprint

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A central goal of neuroscience is to understand how the brain synthesises information from multiple inputs to give rise to a unified conscious experience. This process is widely believed to require integration of information. Here, we combine information theory and network science to address two fundamental questions: how is the human information-processing architecture functionally organised? And how does this organisation support human consciousness? To address these questions, we leverage the mathematical framework of Integrated Information Decomposition to delineate a cognitive architecture wherein specialised modules interact with a “synergistic global workspace,” comprising functionally distinct gateways and broadcasters. Gateway regions gather information from the specialised modules for processing in the synergistic workspace, whose contents are then further integrated to later be made widely available by broadcasters. Through data-driven analysis of resting-state functional MRI, we reveal that gateway regions correspond to the brain’s well-known default mode network, whereas broadcasters of information coincide with the executive control network. Demonstrating that this synergistic workspace supports human consciousness, we further apply Integrated Information Decomposition to BOLD signals to compute integrated information across the brain. By comparing changes due to propofol anaesthesia and severe brain injury, we demonstrate that most changes in integrated information happen within the synergistic workspace. Furthermore, it was found that loss of consciousness corresponds to reduced integrated information between gateway, but not broadcaster, regions of the synergistic workspace. Thus, loss of consciousness may coincide with breakdown of information integration by this synergistic workspace of the human brain. Together, these findings demonstrate that refining our understanding of information-processing in the human brain through Integrated Information Decomposition can provide powerful insights into the human neurocognitive architecture, and its role in supporting consciousness.

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“…The characterization of the temporal latency structure in resting may represent a complementary tool for studying brain communication patterns by using fMRI BOLD signals (Mitra and Raichle, 2018). This approach would be highly relevant for the study of altered state of consciousness, for which the transmission, processing of information, as well as the complexity of communication seem disrupted, as suggested by evidence from transcranial magnetic stimulation (Casarotto et al, 2016) and audio stimulus fMRI studies (Naci et al, 2018). By using the time-delay approach, different source or sink brain regions related to high-order functions, such as perception, working memory, and processing of the stimulus, required for the emergence of consciousness, could be further investigated by analyzing their time-delay behaviors (Basar and Düzgün, 2016;Persuh et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Time-Delay Latency of Resting-State Blood Oxygen Level-Dependent Signal Related to the Level of Consciousness in Patients with Severe Consciousness Impairment

et al. 2020

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Recent evidence on resting-state functional magnetic resonance imaging (rs-fMRI) suggests that healthy human brains have a temporal organization represented in a widely complex time-delay structure. This structure seems to underlie brain communication flow, integration/propagation of brain activity, as well as information processing. Therefore, it is probably linked to the emergence of highly coordinated complex brain phenomena, such as consciousness. Nevertheless, possible changes in this structure during an altered state of consciousness remain poorly investigated. In this work, we hypothesized that due to a disruption in high-order functions and alterations of the brain communication flow, patients with disorders of consciousness (DOC) might exhibit changes in their time-delay structure of spontaneous brain activity. We explored this hypothesis by comparing the time-delay projections from fMRI resting-state data acquired in resting state from 48 patients with DOC and 27 healthy controls (HC) subjects. Results suggest that time-delay structure modifies for patients with DOC conditions when compared with HC. Specifically, the average value and the directionality of latency inside the midcingulate cortex (mCC) shift with the level of consciousness. In particular, positive values of latency inside the mCC relate to preserved states of consciousness, whereas negative values change proportionally with the level of consciousness in patients with DOC. These results suggest that the mCC may play a critical role as an integrator of brain activity in HC subjects, but this role vanishes in an altered state of consciousness.

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Functional diversity of brain networks supports consciousness and verbal intelligence

Cited by 17 publications

References 82 publications

Dynamic Cortical Connectivity during General Anesthesia in Surgical Patients

Dynamic Cortical Connectivity during General Anesthesia in Surgical Patients

A Synergistic Workspace for Human Consciousness Revealed by Integrated Information Decomposition

Time-Delay Latency of Resting-State Blood Oxygen Level-Dependent Signal Related to the Level of Consciousness in Patients with Severe Consciousness Impairment

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