Western Institute for Neuroscience, Department of Physics and Astronomy, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada.
Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, United Kingdom.
Commun Biol. 2023 Jul 5;6(1):692. doi: 10.1038/s42003-023-05063-y.
Integrated Information Theory was developed to explain and quantify consciousness, arguing that conscious systems consist of elements that are integrated through their causal properties. This study presents an implementation of Integrated Information Theory 3.0, the latest version of this framework, to functional MRI data. Data were acquired from 17 healthy subjects who underwent sedation with propofol, a short-acting anaesthetic. Using the PyPhi software package, we systematically analyze how Φ, a measure of integrated information, is modulated by the sedative in different resting-state networks. We compare Φ to other proposed measures of conscious level, including the previous version of integrated information, Granger causality, and correlation-based functional connectivity. Our results indicate that Φ presents a variety of sedative-induced behaviours for different networks. Notably, changes to Φ closely reflect changes to subjects' conscious level in the frontoparietal and dorsal attention networks, which are responsible for higher-order cognitive functions. In conclusion, our findings present important insight into different measures of conscious level that will be useful in future implementations to functional MRI and other forms of neuroimaging.
综合信息理论是为了解释和量化意识而发展起来的，它认为意识系统由通过因果关系属性整合的元素组成。本研究将综合信息理论 3.0 的实现，即该框架的最新版本，应用于功能磁共振成像数据。数据来自 17 名接受异丙酚镇静的健康受试者，异丙酚是一种短效麻醉剂。使用 PyPhi 软件包，我们系统地分析了 Φ，即综合信息的一个度量，如何被镇静剂在不同的静息态网络中调制。我们将 Φ 与其他提出的意识水平度量进行比较，包括综合信息的前一个版本、格兰杰因果关系和基于相关的功能连接。我们的结果表明，对于不同的网络，Φ 呈现出多种镇静诱导的行为。值得注意的是，Φ 的变化与受试者在额顶和背侧注意网络中的意识水平变化密切相关，这些网络负责更高阶的认知功能。总之，我们的发现为功能磁共振成像和其他形式的神经影像学的未来实现提供了对不同意识水平度量的重要见解。
