Journal of Consciousness Studies
August 1, 2024
A. Hudetz
The debate over whether consciousness is unidimensional or consists of multiple fundamental dimensions is examined. Clinical assessment distinguishes awareness (content) from wakefulness (arousal), but this conflates first-person experience with third-person observation. The state of consciousness is better defined by subjective level and content, which are interdependent, with wakefulness as a predisposing factor. Unidimensional models fail to capture the variety of qualitatively different experiences in normal and altered states. Cognitive and abstract multidimensional models have been proposed but lack axiomatic support. A novel multidimensional characterization based on the brain's macroscale functional geometry offers an alternative, empirically grounded model whose dimensions are defined by neurofunctional attributes, representing the state of consciousness as a point in functional space.
Nature Communications
January 5, 2023
Zirui Huang, G. Mashour, A. Hudetz
Dimensions of consciousness such as wakefulness and awareness are encoded in multiple neurofunctional dimensions of the brain's cortical geometry. Disruptions of consciousness from pharmacological, neuropathological, or psychiatric causes degrade one or more major cortical gradients depending on the condition. Network-specific reconfigurations within this multidimensional gradient space are associated with behavioral unresponsiveness across various etiologies, and these spatial reconfigurations correlate with a temporal disruption of structured transitions of dynamic brain states. The work provides a unifying neurofunctional framework for multiple dimensions of human consciousness in both health and disease.
Science Advances
March 1, 2020
Zirui Huang, Jun Zhang, Jinsong Wu et al.
Consciousness depends on frequent access between two key brain networks: the default mode network and the dorsal attention network, which normally alternate their activity in an anticorrelated manner. A 'temporal circuit' of dynamic brain activity trajectories regulates transitions between these networks. Balanced reciprocal accessibility of brain states within this circuit characterizes consciousness, while isolation of the networks from the temporal circuit is associated with unresponsiveness from various causes. These findings advance understanding of how anticorrelated brain systems support consciousness.
Frontiers in Human Neuroscience
February 16, 2018
Hyoungkyu Kim, A. Hudetz, Joseph Lee et al.
A practical method estimates integrated information (Φ), a measure proposed by integrated information theory to be related to consciousness, from 128-channel EEG. The method alone cannot distinguish certain anesthetic states, but combining Φ with four EEG connectivity parameters—power, frequency, functional connectivity, and modularity—differentiates all states of consciousness. The association of Φ with EEG connectivity during anesthesia offers a new approach to applying the theory, potentially useful for characterizing consciousness in sleep, anesthesia, and coma.