Global workspace theory of consciousness: toward a cognitive neuroscience of human experience

Baars, Bernard J.

doi:10.1016/s0079-6123(05)50004-9

Cited by 584 publications

(435 citation statements)

References 30 publications

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“…Scan parameters consisted of a 10-ms repetition time, 14 ms echo time, 10°flip angle, 216 mm × 216-mm in-plane field of view, 72 × 72 matrix, and 40 slices (covering 120 mm superior-inferior). Each functional scan included either 410 brain volumes (subjects 1-12) or 545 brain volumes (subjects [13][14][15][16][17][18][19][20][21][22][23][24].…”

Section: Methodsmentioning

confidence: 99%

“…By contrast, network-level theories posit that awareness is tightly associated with activation of parietofrontal attention networks of the brain (5)(6)(7)(8)(9)(10)(11). Finally, global models propose that awareness results from widespread changes in the activation state (12)(13)(14)(15) and functional connectivity (16)(17)(18)(19) of the brain. Though there is strong experimental support for network-level theories, there is scant experimental evidence in favor of truly sweeping, widespread changes in brain activity with conscious perception despite the fact that global scale models have recently come to prominence in the theoretical landscape of this field.…”

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confidence: 99%

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Breakdown of the brain’s functional network modularity with awareness

Godwin¹,

Barry

Marois

2015

Proc. Natl. Acad. Sci. U.S.A.

130

106

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Neurobiological theories of awareness propose divergent accounts of the spatial extent of brain changes that support conscious perception. Whereas focal theories posit mostly local regional changes, global theories propose that awareness emerges from the propagation of neural signals across a broad extent of sensory and association cortex. Here we tested the scalar extent of brain changes associated with awareness using graph theoretical analysis applied to functional connectivity data acquired at ultra-high field while subjects performed a simple masked target detection task. We found that awareness of a visual target is associated with a degradation of the modularity of the brain's functional networks brought about by an increase in intermodular functional connectivity. These results provide compelling evidence that awareness is associated with truly global changes in the brain's functional connectivity.awareness | graph theory | functional connectivity | consciousness T hree broad classes of models have been proposed to explain the neural basis of awareness, with these classes primarily differing on the predicted extent of neural information changes associated with conscious perception. According to focal theories, awareness results from local changes in neural activity in either the perceptual substrates (1-3) or in higher-level nodes of information processing pathways (4). By contrast, network-level theories posit that awareness is tightly associated with activation of parietofrontal attention networks of the brain (5-11). Finally, global models propose that awareness results from widespread changes in the activation state (12-15) and functional connectivity (16-19) of the brain. Though there is strong experimental support for network-level theories, there is scant experimental evidence in favor of truly sweeping, widespread changes in brain activity with conscious perception despite the fact that global scale models have recently come to prominence in the theoretical landscape of this field.Using a graph theoretical approach applied to ultra-high-field fMRI data, here we experimentally tested a key tenet of global theories: the widespread emergence of large-scale functional connectivity with awareness. Graph theory analyses are ideal tools to test global models of awareness because they can provide concise measures of the integration and segregation of interconnected nodes of a system (20). Applied to functional imaging data, we treat individual brain regions of interest (ROIs) as nodes, functional connectivity between ROIs as edges, and functional brain networks as interconnected modules of nodes. When examining a large set of ROIs that encompass the different networks of the human cerebral cortex (21, 22), we can apply graph theory analyses to estimate the extent to which key measures of global information processing are altered by the state of awareness. This approach has been previously applied to study differences in cognitive states (23)(24)(25)(26)(27)(28)(29)(30)(31). Although recent studies have t...

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Breakdown of the brain’s functional network modularity with awareness

Godwin¹,

Barry

Marois

2015

Proc. Natl. Acad. Sci. U.S.A.

130

106

View full text Add to dashboard Cite

show abstract

“…In particular, the recruitment of frontal and parietal associative cortices has repeatedly been associated with conscious representations (Dehaene et al, 2006;Laureys et al, 1999;Rees et al, 2002). These areas are thought to materialize a global workspace in which unified and integrated mental representations reach consciousness (Baars, 2005). The second aim of the present paper was to assess quantitatively the functional integration between frontal and parietal areas during resting wakefulness and general anesthesia.…”

Section: Introductionmentioning

confidence: 91%

Brain functional integration decreases during propofol-induced loss of consciousness

et al. 2011

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Consciousness has been related to the amount of integrated information that the brain is able to generate.In this paper, we tested the hypothesis that the loss of consciousness caused by propofol anesthesia is associated with a significant reduction in the capacity of the brain to integrate information. To assess the functional structure of the whole brain, functional integration and partial correlations were computed from fMRI data acquired from 18 healthy volunteers during resting wakefulness and propofol-induced deep sedation. Total integration was significantly reduced from wakefulness to deep sedation in the whole brain as well as within and between its constituent networks (or systems). Integration was systematically reduced within each system (i.e., brain or networks), as well as between networks. However, the ventral attentional network maintained interactions with most other networks during deep sedation. Partial correlations further suggested that functional connectivity was particularly affected between parietal areas and frontal or temporal regions during deep sedation. Our findings suggest that the breakdown in brain integration is the neural correlate of the loss of consciousness induced by propofol. They stress the important role played by parietal and frontal areas in the generation of consciousness.

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“…A second theory that is discussed here is the global workspace theory, according to which widespread broadcasting of information in the brain is necessary for consciousness (Baars, 2005). It has previously been suggested that the global workspace theory fails to explain conscious odor perception (Young, 2012).…”

Section: Theory Testing In Olfactionmentioning

confidence: 99%

Olfactory Consciousness across Disciplines

2015

Frontiers Research Topics

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Although vision is the de facto model system of consciousness research, studying olfactory consciousness has its own advantages, as this collection of articles emphatically demonstrates. One advantage of olfaction is its computational and phenomenological simplicity, which facilitates the identification of basic principles. Other researchers study olfactory consciousness not because of its simplicity, but because of its unique features. Together, olfaction's simplicity and its distinctiveness make it an ideal system for testing theories of consciousness. In this research topic, the results of recent research into olfactory consciousness are presented.

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Global workspace theory of consciousness: toward a cognitive neuroscience of human experience

Cited by 584 publications

References 30 publications

Breakdown of the brain’s functional network modularity with awareness

Breakdown of the brain’s functional network modularity with awareness

Brain functional integration decreases during propofol-induced loss of consciousness

Olfactory Consciousness across Disciplines

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