Statistical diversity distinguishes global states of consciousness
Joseph Starkey, Robin Carhart-Harris, Andrea Pigorini, Lino Nobili, Adam B. Barrett
bioRxiv December 7, 2023 preprint DOI: 10.1101/2023.12.05.570101 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational study |
|---|---|
| Population | Humans |
| Interventions | ketamine lysergic acid diethylamide (LSD) psilocybin |
| Keywords | Consciousness states States of awareness Levels of consciousness Conscious states Brain states States of consciousness Brain activity analysis Brain signal analysis Neural activity analysis Brain pattern analysis Neurophysiological analysis Brain signal diversity Statistical neuroscience Neurostatistics Quantitative neuroscience Brain signal statistics Statistical brain patterns Neural markers Brain markers Biomarkers of consciousness Neural signatures Brain signal markers Objective metric |
| Key findings | Statistical complexity differentiates sleep stages and increases under ketamine, LSD, and psilocybin relative to placebo. |
Abstract
Abstract Application of complexity measures to neurophysiological time series has seen increased use in recent years to identify neural correlates of global states of consciousness. Lempel-Ziv complexity is currently the de-facto complexity measure used in these investigations. However, by simply counting the number of patterns, this measure theoretically takes its maximum value for data that are completely random. Recently, a measure of ‘statistical complexity’ - which calculates the diversity of statistical interactions - has been devised which aims to account for and remove randomness seen in data. It was recently found that this measure decreases during anaesthesia in fruit flies. This paper investigates this statistical complexity measure on human neurophysiology data from different stages of sleep, and from individuals under the effects of three psychedelic substances: ketamine, lysergic acid diethylamide (LSD), and psilocybin. Results indicate that statistical complexity: (i) differentiates the different stages of sleep analogously to Lempel-Ziv complexity; (ii) increases relative to placebo for all three psychedelic substances. Thus, statistical complexity is a useful alternative measure for investigating the complexity of neural activity associated with different states of consciousness.