|
The neural correlates of consciousness (NCC) constitute the minimal set of neuronal events and mechanisms sufficient for a specific conscious percept.〔Koch 2004, p. 304.〕 Neuroscientists use empirical approaches to discover neural correlates of subjective phenomena.〔See (here ) for a glossary of related terms.〕 The set should be ''minimal'' because, under the assumption that the brain is sufficient to give rise to any given conscious experience, the question is which of its components is necessary to produce it. ==Neurobiological approach to consciousness== A science of consciousness must explain the exact relationship between subjective mental states and brain states, the nature of the relationship between the conscious mind and the electro-chemical interactions in the body. Progress in neurophilosophy has come from focusing on the body rather than the mind. In this context the neuronal correlates of consciousness may be viewed as its causes, and consciousness may be thought of as a state-dependent property of some undefined complex, adaptive, and highly interconnected biological system.〔Squire 2008, p. 1223.〕 Discovering and characterizing neural correlates does not offer a theory of consciousness that can explain how particular systems experience anything at all, or how they are associated with consciousness, the so-called hard problem of consciousness,〔Kandel 2007, p. 382.〕 but understanding the NCC may be a step toward such a theory. Most neurobiologists assume that the variables giving rise to consciousness are to be found at the neuronal level, governed by classical physics, though a few scholars have proposed theories of quantum consciousness based on quantum mechanics.〔(【引用サイトリンク】author=Jeffrey M. Schwartz, Henry P. Stapp, Mario Beauregard )〕 There is great apparent redundancy and parallelism in neural networks so, while activity in one group of neurons may correlate with a percept in one case, a different population might mediate a related percept if the former population is lost or inactivated. It may be that every phenomenal, subjective state has a neural correlate. Where the NCC can be induced artificially the subject will experience the associated percept, while perturbing or inactivating the region of correlation for a specific percept will affect the percept or cause it to disappear, giving a cause-effect relationship from the neural region to the nature of the percept. What characterizes the NCC? What are the commonalities between the NCC for seeing and for hearing? Will the NCC involve all the pyramidal neurons in the cortex at any given point in time? Or only a subset of long-range projection cells in the frontal lobes that project to the sensory cortices in the back? Neurons that fire in a rhythmic manner? Neurons that fire in a synchronous manner? These are some of the proposals that have been advanced over the years.〔See Chalmers 1998, available online.〕 The growing ability of neuroscientists to manipulate neurons using methods from molecular biology in combination with optical tools (e.g., Adamantidis et al. 2007) depends on the simultaneous development of appropriate behavioral assays and model organisms amenable to large-scale genomic analysis and manipulation. It is the combination of such fine-grained neuronal analysis in animals with ever more sensitive psychophysical and brain imaging techniques in humans, complemented by the development of a robust theoretical predictive framework, that will hopefully lead to a rational understanding of consciousness, one of the central mysteries of life. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Neural correlates of consciousness」の詳細全文を読む スポンサード リンク
|