2015/09/14 by Enzo Tagliazucchi, Tagliazucchi, Enzo, Dante R. Chialvo +14 · 2 citations
Biochemistry, Genetics and Molecular Biology · Neuroscience · Psychology · #EEG and Brain-Computer Interfaces #FOS: Biological sciences #Functional Brain Connectivity Studies #Neural dynamics and brain function #Neurons and Cognition (q-bio.NC) #Paranormal Experiences and Beliefs #q-bio.NC
paper · pdf · doi:10.48550/arxiv.1509.04304
to appear in Journal of the Royal Society Interface
openalex publication_date 2015/09/14 · arxiv created 2015/12/23 · arxiv updated 2015/12/24 · openalex created_date 2022/10/03 · openalex updated_date 2026/07/28
Loss of cortical integration and changes in the dynamics of electrophysiological brain signals characterize the transition from wakefulness towards unconsciousness. The common mechanism underlying these observations remains unknown. In this study we arrive at a basic model, which explains these empirical observations based on the theory of phase transitions in complex systems. We studied the link between spatial and temporal correlations of large-scale brain activity recorded with functional magnetic resonance imaging during wakefulness, propofol-induced sedation and loss of consciousness, as well as during the subsequent recovery. We observed that during unconsciousness activity in frontal and thalamic regions exhibited a reduction of long-range temporal correlations and a departure of functional connectivity from the underlying anatomical constraints. These changes in dynamics and anatomy-function coupling were correlated across participants, suggesting that temporal complexity and an efficient exploration of anatomical connectivity are inter-related phenomena. A model of a system exhibiting a phase transition reproduced our findings, as well as the diminished sensitivity of the cortex to external perturbations during unconsciousness. This theoretical framework unifies different empirical observations about brain activity during unconsciousness and predicts that the principles we identified are universal and independent of the causes behind loss of awareness.