Skip to content

Measures of entropy and complexity in altered states of consciousness

Diego M. Mateos, Ramon Guevara Erra, Richard Wennberg, J. L. Perez Velazquez

Cognitive Neurodynamics October 20, 2017 DOI: 10.1007/s11571-017-9459-8 (opens in new tab)

Read Full Text
Relevant Not relevant

Study at a glance

AI-extracted from the abstract
Characteristics Observational study Peer reviewed
Population Subjects during resting wakefulness, different sleep stages, and epileptic seizures
Topics Altered states of consciousness
Citations 124
Key findings Entropy and complexity of brain signals are greatest during fully alert states and decrease during states with loss of awareness or consciousness.

Abstract

Quantification of complexity in neurophysiological signals has been studied using different methods, especially those from information or dynamical system theory. These studies have revealed a dependence on different states of consciousness, and in particular that wakefulness is characterized by a greater complexity of brain signals, perhaps due to the necessity for the brain to handle varied sensorimotor information. Thus, these frameworks are very useful in attempts to quantify cognitive states. We set out to analyze different types of signals obtained from scalp electroencephalography (EEG), intracranial EEG and magnetoencephalography recording in subjects during different states of consciousness: resting wakefulness, different sleep stages and epileptic seizures. The signals were analyzed using a statistical (permutation entropy) and a deterministic (permutation Lempel-Ziv complexity) analytical method. The results are presented in complexity versus entropy graphs, showing that the values of entropy and complexity of the signals tend to be greatest when the subjects are in fully alert states, falling in states with loss of awareness or consciousness. These findings were robust for all three types of recordings. We propose that the investigation of the structure of cognition using the frameworks of complexity will reveal mechanistic aspects of brain dynamics associated not only with altered states of consciousness but also with normal and pathological conditions.

Comparable studies

Other observational and cohort studies on altered states of consciousness, most cited first.

Study Year Design Participants
Neural correlates of the DMT experience assessed with multivariate EEG. 6 female, 7 male human participants 2019 Observational cohort n = 13
Altered States of Consciousness and Short-Term Psychological After-Effects Induced by the First Time Ritual Use of Ayahuasca in an Urban Context in Brazil First-time ayahuasca users in Santo Daime and União do Vegetal rituals 2005 Observational cohort n = 28
Quantifying arousal and awareness in altered states of consciousness using interpretable deep learning Healthy individuals during sleep, individuals under general anesthesia, and patients... 2022 Observational cohort n = 71
Subanaesthetic ketamine and altered states of consciousness in humans Human volunteers 2018 Observational study n = 15
Neural and subjective effects of inhaled N,N-dimethyltryptamine in natural settings. Healthy and experienced participants 2021 Observational field study n = 35

Citations in the library

Cited by 32

and 27 more in the library

Cites 6

and 1 more in the library

Related reading

Explore topics

Altered states of consciousness Addiction Philosophy of mind