%0 Journal Article
%T An information integration theory of consciousness
%A Giulio Tononi
%J BMC Neuroscience
%D 2004
%I BioMed Central
%R 10.1186/1471-2202-5-42
%X 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 ¨C the availability of a very large number of conscious experiences; and integration ¨C the unity of each such experience. The theory states that the quantity of consciousness available to a system can be measured as the ¦µ value of a complex of elements. ¦µ 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 ¦µ>0 that is not part of a subset of higher ¦µ. 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.Consciousness is everything we experience. Think of it as what abandons us every night when we fall into dreamless sleep and
%U http://www.biomedcentral.com/1471-2202/5/42