Integration and segregation in whole-brain networks: implications for altered states of consciousness
Oxford University Research Archive (ORA) January 1, 2018 Louis-David Lord
The brain must balance integrating information across regions with segregating it into specialized modules. This thesis examines that balance in two altered states of consciousness: slow-wave sleep and the psychedelic experience from psilocybin. Using fMRI data, a novel method identifies highly integrative brain nodes based on persistent homology, which have high betweenness-centrality and participation coefficient but avoid dense clusters. Global synchrony and metastability decrease in slow-wave sleep while chimeraness increases; opposite effects occur under psilocybin. Psilocybin increases occurrence of a globally coherent functional connectivity state and decreases occupancy of a fronto-parietal control network.