Entropy
January 30, 2019
Aline Viol, Fernanda Palhano-Fontes, Heloisa Onias et al.
37 citations
A new network metric, geodesic entropy, measures the Shannon entropy of distances from one node to all others in a network, characterizing how much influence a node has based on the overall network structure. Applied to resting-state functional brain networks of humans, the metric differentiates ordinary consciousness from the altered state induced by Ayahuasca ingestion. On average, functional networks from subjects in the altered state show larger geodesic entropy than those in the ordinary state, suggesting the metric can reveal differences in brain network organization across states of consciousness.
Journal of Physics Complexity
March 1, 2023
Aline Viol, G. M. Viswanathan, Oleksandra Soldatkina et al.
4 citations
The physical basis of consciousness is a central open question in science. This work compares resting-state functional brain networks of individuals before and after ingesting the psychedelic brew Ayahuasca. Using a measure called pairwise information parity, which quantifies statistical symmetries between brain region connections across the entire network, the authors found an increase in average information parity under psychedelic influence. Notably, information parity between regions of the limbic system and frontal cortex was consistently higher for all individuals while under the influence. These findings suggest that the resemblance of statistical influences between pairs of brain region activities tends to increase under Ayahuasca, possibly as a mechanism to maintain network functional resilience.
arXiv Preprint Archive
September 26, 2018
A. Viol, Fernanda Palhano-Fontes, Heloisa Onias et al.
A new network metric called geodesic entropy quantifies the Shannon entropy of the distance distribution from each node to all others, capturing the structural role of individual nodes in a network. Applied to functional brain networks of humans in two states of consciousness—ordinary waking and after ingestion of Ayahuasca—the metric distinguished the states. Brain networks under Ayahuasca showed, on average, larger geodesic entropy than those in the ordinary waking state. The authors suggest geodesic entropy is a useful tool for analyzing complex networks and may improve understanding of emergent behaviors such as self-organized criticality.