PLoS Computational Biology
October 16, 2014
Srivas Chennu, Paola Finoia, Evelyn Kamau et al.
249 citations
Consciousness is thought to require balanced integration and differentiation of brain activity, supported by efficient networks. Analyzing high-density EEG from 32 patients with chronic disorders of consciousness and healthy controls, the authors found that patient networks showed reduced local and global efficiency and fewer hubs in the alpha frequency band. A new metric, modular span, revealed that alpha network modules in patients were spatially limited, lacking the long-distance interactions seen in controls. However, delta and theta band networks were partially reversed and more similar to each other in patients. Alpha network efficiency correlated with behavioral awareness. Notably, some behaviorally unresponsive vegetative patients with covert awareness had well-preserved alpha networks resembling controls, suggesting network mechanisms that may support consciousness despite severe behavioral impairment.
Cerebral cortex (New York, N.Y. : 1991)
June 30, 2020
Andrés Canales-Johnson, Alexander J Billig, Francisco A Olivares et al.
51 citations
During auditory bistable perception, a sequence of tones can be heard either as a single stream (integrated percept) or as two parallel streams (differentiated percept). Neural recordings showed that when perceptual alternations arose spontaneously, the integrated percept corresponded to increased neural information integration and decreased neural information differentiation across frontoparietal regions, while the differentiated percept showed the opposite pattern. When perception was driven by an external change in the sound stream, neural oscillatory power distinguished between percepts but information measures did not. The findings demonstrate that integration and differentiation of conscious perception map onto theoretically motivated neural information signatures, suggesting a direct link between phenomenology and neurophysiology.
Neuroimage
February 9, 2021
Riku Ihalainen, Olivia Gosseries, Frederik van de Steen et al.
30 citations
Using dynamic causal modelling of high-density EEG recordings from 10 people during propofol anaesthesia, the study evaluated how three resting state networks—the default mode network, the salience network, and the central executive network—contribute to consciousness. Loss of consciousness reduced inter-network connectivity in the parietal cortex, especially feed-forward frontoparietal and parietal connections at the precuneus node within the default mode network. Within the salience and central executive networks, unconsciousness generated small increases in bidirectional connectivity. The most consistent predictions of consciousness came from a key set of frontoparietal connections, supporting the importance of the posterior hot zone in explaining loss of consciousness.
Journal of Cognitive Neuroscience
January 1, 2023
Rajanikant Panda, Audrey Vanhaudenhuyse, Andrea Piarulli et al.
15 citations
During hypnosis, brain connectivity changes in ways that suggest more efficient cognitive processing and less mind-wandering. In nine healthy participants, hypnosis increased delta-wave connections between frontal brain regions and between frontal and parietal regions. It decreased alpha and beta-2 connections among frontal, parietal, and midline areas. Network analysis showed greater segregation of short-range connections in delta and alpha bands and greater integration of long-range connections in beta-2 bands. Frontal and right parietal electrodes became central hubs. These altered dynamics may reflect a modified balance between internal and external awareness networks.
arXiv Preprint Archive
February 6, 2020
Marco Alberto Javarone, Olivia Gosseries, Daniele Marinazzo et al.
A mean-field model inspired by Integrated Information Theory and Tegmark's representation of consciousness analyzes order-disorder phase transitions on Curie-Weiss models generated from EEG signals recorded on healthy individuals undergoing deep sedation. A machine learning tool classifies mental states using critical temperatures computed from these models. The method discriminates between states of awareness and deep sedation. A state space representing the path between mental states is identified, with dimensions corresponding to critical temperatures over different EEG frequency bands. The method may have clinical applications.
Scientific Reports
June 20, 2019
Laura Sophie Imperatori, Monica Betta, Luca Cecchetti et al.
Two methods for measuring brain connectivity, wPLI and wSMI, detect different types of neural interactions. Using simulated EEG data, wPLI is sensitive to couplings that mix linear and nonlinear dependencies, while only wSMI detects purely nonlinear interactions. In real EEG recordings from 12 healthy adults during wakefulness and deep sleep, both methods showed different sensitivity to changes in brain connectivity across these states. The findings suggest that using both methods together provides a more complete picture of the functional basis of consciousness in both healthy and altered states.
Frontiers in Human Neuroscience
January 1, 2016
Rajanikant Panda, Rose D Bharath, Neeraj Upadhyay et al.
Meditation alters both the spatial extent and the temporal dynamics of the default mode network (DMN). Using simultaneous EEG and fMRI, experienced meditators showed reduced activity in the posterior cingulate hub of the DMN and increased activity in right frontal and left temporal areas compared to healthy controls, both during rest and during meditation. EEG analysis revealed that the DMN-related microstate occurred more frequently and lasted longer in meditators, and these parameters increased further during meditation. The change in microstate duration when entering meditation correlated negatively with years of experience, indicating that long-term practice produces durable changes in DMN dynamics.