Self-organized criticality as a framework for consciousness: A review study

Self-organized criticality (SOC) is a property of neural systems that may serve as a unifying framework for theories of consciousness. A review of 71 publications from 1998 to 2021 found that annual citations increased steadily; original articles made up 50.7% and reviews or theoretical articles 43.6%. Human data were reported in 16 studies, animal data in 7, and computational models in 12. EEG/MEG studies used diverse analytical tools—detrended fluctuation analysis, pair correlation function, neuronal avalanche parameters, and spectral exponent—to assess criticality. Critical dynamics align with global workspace theory and integrated information theory, but the small number of experimental studies and heterogeneity of methods limit generalizability.

Study at a glance

Abstract

ObjectiveNo current model of consciousness is univocally accepted on either theoretical or empirical grounds, and the need for a solid unifying framework is evident. Special attention has been given to the premise that self-organized criticality (SOC) is a fundamental property of neural system. SOC provides a competitive model to describe the physical mechanisms underlying spontaneous brain activity, and thus, critical dynamics were proposed as general gauges of information processing representing a strong candidate for a surrogate measure of consciousness. As SOC could be a neurodynamical framework, which may be able to bring together existing theories and experimental evidence, the purpose of this work was to provide a comprehensive overview of progress of research on SOC in association with consciousness.MethodsA comprehensive search of publications on consciousness and SOC published between 1998 and 2021 was conducted. The Web of Science database was searched, and annual number of publications and citations, type of articles, and applied methods were determined.ResultsA total of 71 publications were identified. The annual number of citations steadily increased over the years. Original articles comprised 50.7% and reviews/theoretical articles 43.6%. Sixteen studies reported on human data and in seven studies data were recorded in animals. Computational models were utilized in n = 12 studies. EcoG data were assessed in n = 4 articles, fMRI in n = 4 studies, and EEG/MEG in n = 10 studies. Notably, different analytical tools were applied in the EEG/MEG studies to assess a surrogate measure of criticality such as the detrended fluctuation analysis, the pair correlation function, parameters from the neuronal avalanche analysis and the spectral exponent.ConclusionRecent studies pointed out agreements of critical dynamics with the current most influencing theories in the field of consciousness research, the global workspace theory and the integrated information theory. Thus, the framework of SOC as a neurodynamical parameter for consciousness seems promising. However, identified experimental work was small in numbers, and a heterogeneity of applied analytical tools as a surrogate measure of criticality was observable, which limits the generalizability of findings.