Communications Biology
July 5, 2023
Idan E Nemirovsky, Nicholas J M Popiel, Jorge Rudas et al.
Integrated Information Theory was developed to explain and quantify consciousness, arguing that conscious systems consist of elements that are integrated through their causal properties. This study presents an implementation of Integrated Information Theory 3.0, the latest version of this framework, to functional MRI data. Data were acquired from 17 healthy subjects who underwent sedation with...
Neuroimage
September 12, 2020
Sivayini Kandeepan, Jorge Rudas, Francisco Gómez et al.
Propofol is a short-acting medication that results in decreased levels of consciousness and is used for general anesthesia. Although it is the most commonly used anesthetic in the world, much remains unknown about the mechanisms by which it induces a loss of consciousness. Characterizing anesthesia-induced alterations to brain network activity might provide a powerful framework for...
Entropy (Basel, Switzerland)
March 16, 2020
Nicholas J M Popiel, Sina Khajehabdollahi, Pubuditha M. Abeyasinghe et al.
Integrated Information Theory (IIT) posits that integrated information ( Φ ) represents the quantity of a conscious experience. Here, the generalized Ising model was used to calculate Φ as a function of temperature in toy models of fully connected neural networks. A Monte-Carlo simulation was run on 159 normalized, random, positively weighted networks analogous to small five-node excitatory...
PLoS One
January 30, 2020
Vanessa Charland-Verville, D. Ribeiro de Paula, Charlotte Martial et al.
20 citations
The notion that death represents a passing to an afterlife, where we are reunited with loved ones and live eternally in a utopian paradise, is common in the reports of people who have encountered a “Near-Death Experience” (NDE). NDEs are thoroughly portrayed by the media but empirical studies are rather recent. The definition of the phenomenon as well as the identification of NDE experiencers...
Functional MRI
December 1, 2018
Nasim Mortazavi, Cécile Staquet, Audrey Vanhaudenhuyse et al.
This chapter reviews current knowledge of the effects of hypnotic anesthetic agents on brain resting-state networks (RSNs) that sustain consciousness. Although full exploration of the networks under anesthesia is not yet available, current evidence indicates that anesthetic agents with hypnotic properties dose-dependently modulate RSN functioning. Each anesthetic agent has specific effects that...
Anesthesiology
August 9, 2016
Vincent Bonhomme, Audrey Vanhaudenhuyse, Athena Demertzi et al.
206 citations
BACKGROUND: Consciousness-altering anesthetic agents disturb connectivity between brain regions composing the resting-state consciousness networks (RSNs). The default mode network (DMn), executive control network, salience network (SALn), auditory network, sensorimotor network (SMn), and visual network sustain mentation. Ketamine modifies consciousness differently from other agents, producing...
Frontiers in Psychology
2012
Lizette Heine, Andrea Soddu, Francisco Gómez et al.
281 citations
In order to better understand the functional contribution of resting state activity to conscious cognition, we aimed to review increases and decreases in functional magnetic resonance imaging (fMRI) functional connectivity under physiological (sleep), pharmacological (anesthesia), and pathological altered states of consciousness, such as brain death, coma, vegetative state/unresponsive...
Progress in Brain Research
2011
Athena Demertzi, Andrea Soddu, M-E Faymonville et al.
Resting state fMRI (functional magnetic resonance imaging) acquisitions are characterized by low-frequency spontaneous activity in a default mode network (encompassing medial brain areas and linked to self-related processes) and an anticorrelated "extrinsic" system (encompassing lateral frontoparietal areas and modulated via external sensory stimulation). In order to better determine the...
Journal of Cognitive Neuroscience
June 1, 2010
Audrey Vanhaudenhuyse, Athena Demertzi, Manuel Schabus et al.
460 citations
Evidence from functional neuroimaging studies on resting state suggests that there are two distinct anticorrelated cortical systems that mediate conscious awareness: an "extrinsic" system that encompasses lateral fronto-parietal areas and has been linked with processes of external input (external awareness), and an "intrinsic" system which encompasses mainly medial brain areas and has been...