An information integration theory of consciousness.
An information integration theory of consciousness.
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DOI：
10.1186/1471-2202-5-42
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发表时间：
2004-11-02
期刊：
影响因子：
2.4
通讯作者：
Tononi G
中科院分区：
文献类型：
--
作者：
Tononi G
意识提出了两个主要问题。第一个是理解决定一个系统在多大程度上具有意识体验的条件。例如，为什么我们的意识是由大脑的某些部分产生的，比如丘脑皮质系统，而不是由其他部分产生的，比如小脑？为什么我们在清醒的时候有意识，而在无梦的睡眠中却很少有意识？第二个问题是理解决定一个系统具有何种意识的条件。例如，为什么大脑的特定部分会为我们的意识体验提供特定的品质，比如视觉和听觉？本文提出了一个关于什么是意识以及如何测量意识的理论。根据该理论，意识对应于系统整合信息的能力。这一主张的动机是意识的两个关键现象学性质：分化--大量意识经验的可用性;整合--每一种意识经验的统一性。该理论指出，系统可用的意识量可以用元素复合体的Φ值来衡量。Φ是可以跨元素子集的信息最薄弱环节整合的因果有效信息量。复形是Φ>0的元素的子集，其不是更高Φ的子集的一部分。该理论还声称，意识的质量是由复合体的元素之间的信息关系决定的，这些信息关系由它们之间的有效信息值指定。最后，每一个特定的意识体验都是由在任何给定时间内，在复合体的元素之间调节信息交互的变量的值来指定的。信息整合理论以一种原则性的方式解释了几种关于意识的神经生物学观察。如图所示，这些因素包括意识与某些神经系统而不是与其他神经系统的关联;意识背后的神经过程可以影响保持无意识的神经过程或被保持无意识的神经过程影响;无梦睡眠和全身性癫痫发作期间意识的减少;以及支持意识的神经相互作用的时间要求。该理论认为，意识是一个基本的量，它是分等级的，它存在于婴儿和动物中，并且应该有可能构建有意识的人工制品。
Consciousness poses two main problems. The first is understanding the conditions that determine to what extent a system has conscious experience. For instance, why is our consciousness generated by certain parts of our brain, such as the thalamocortical system, and not by other parts, such as the cerebellum? And why are we conscious during wakefulness and much less so during dreamless sleep? The second problem is understanding the conditions that determine what kind of consciousness a system has. For example, why do specific parts of the brain contribute specific qualities to our conscious experience, such as vision and audition? This paper presents a theory about what consciousness is and how it can be measured. According to the theory, consciousness corresponds to the capacity of a system to integrate information. This claim is motivated by two key phenomenological properties of consciousness: differentiation – the availability of a very large number of conscious experiences; and integration – the unity of each such experience. The theory states that the quantity of consciousness available to a system can be measured as the Φ value of a complex of elements. Φ is the amount of causally effective information that can be integrated across the informational weakest link of a subset of elements. A complex is a subset of elements with Φ>0 that is not part of a subset of higher Φ. The theory also claims that the quality of consciousness is determined by the informational relationships among the elements of a complex, which are specified by the values of effective information among them. Finally, each particular conscious experience is specified by the value, at any given time, of the variables mediating informational interactions among the elements of a complex. The information integration theory accounts, in a principled manner, for several neurobiological observations concerning consciousness. As shown here, these include the association of consciousness with certain neural systems rather than with others; the fact that neural processes underlying consciousness can influence or be influenced by neural processes that remain unconscious; the reduction of consciousness during dreamless sleep and generalized seizures; and the time requirements on neural interactions that support consciousness. The theory entails that consciousness is a fundamental quantity, that it is graded, that it is present in infants and animals, and that it should be possible to build conscious artifacts.