Journal of Cognitive Neuroscience
June 1, 2010
Audrey Vanhaudenhuyse, Athena Demertzi, Manuel Schabus et al.
460 citations
Resting brain activity reveals two anticorrelated cortical systems linked to conscious awareness: an extrinsic system (lateral fronto-parietal areas) associated with external awareness and an intrinsic system (medial brain areas) associated with internal awareness. In 31 healthy volunteers, external and internal awareness were significantly anticorrelated, with a mean switching frequency of 0.05 Hz, similar to BOLD fMRI slow oscillations. In 22 volunteers, fMRI showed that precuneus/posterior cingulate, anterior cingulate/mesiofrontal cortices, and parahippocampal areas (intrinsic system) correlated with internal awareness, while lateral fronto-parietal cortices (extrinsic system) correlated with external awareness.
Anesthesiology
August 9, 2016
Vincent Bonhomme, Audrey Vanhaudenhuyse, Athena Demertzi et al.
206 citations
Ketamine alters consciousness by disrupting connectivity within and between specific resting-state brain networks, particularly the default mode network (DMn) and salience network (SALn), while leaving sensory and motor networks largely intact. In healthy volunteers given stepwise ketamine infusions until they lost responsiveness, DMn connectivity between the medial prefrontal cortex and other network regions decreased (from 0.20 to 0.07), and the normal anticorrelated activity between the DMn and sensory regions reversed (e.g., right sensory cortex shifted from -0.07 to 0.04). SALn connectivity was also suppressed but nonuniformly. These specific changes, including preserved sensory network connectivity, are shared with propofol-induced unconsciousness.
bioRxiv Preprint Server
January 15, 2019
Sina Khajehabdollahi, Pubuditha M. Abeyasinghe, Adrian M. Owen et al.
preprint
Using the critical Ising model of the brain, integrated information—a measure of consciousness—was measured in toy models of generic neural networks. Monte Carlo simulations were run on 159 random weighted networks analogous to small 5-node neural network motifs. Integrated information, as a type of order parameter like magnetism, undergoes a phase transition at the model's critical point, where the system's 'consciousness' is maximally susceptible to perturbations and on the boundary between ordered and disordered forms. This adds evidence that the emergence of consciousness coincides with self-organized criticality, evolution, the emergence of complexity, and the integration of complex systems.