Brain and consciousness
Brain and consciousness
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大脑和意识
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发表时间：
2002
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通讯作者：
A. FernándezdeMolinayCañas
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作者：
A. FernándezdeMolinayCañas
简要回顾了意识的哲学和生物学概念，从亚里士多德到笛卡尔，再到过去 15 年的现代神经生物学家。讨论了CRICK的皮质丘脑整合观、Edelman的初级和高级意识概念以及Edelman和Tononi的动态核心概念。随后报道了Llinas的皮质丘脑共振理论。利纳斯理论的核心是中枢神经系统中神经元的电固有特性的存在，这使得它们能够以不同的频率振荡，如果膜特性适合的话，也可以在特定频率下共振。这种振荡和神经元连接导致皮质丘脑动态环路特异性和非特异性。特定丘脑核团的动态皮质丘脑环直接或通过第 4 层的抑制性中间神经元与第 5 层和第 6 层的金字塔连接。金字塔的节律放电刺激丘脑特定神经元，并间接通过网状神经元在特定中继神经元中产生反弹爆发。皮质抑制性中间神经元的振荡特性启动循环回路的作用，其功能是将感觉通路的内容告知大脑皮层。另一方面，非特异性核团（特别是层内核团）的丘脑皮质共振环与第一层金字塔的顶端树突连接，其放电直接并通过网状核到达丘脑中继神经元。临床和 MEG 数据与层内核的作用一致，即为特定通路传递的感觉特定信息提供结合信号。通过这种方式，非特异性皮质丘脑环将充当沿着树突顶轴与特定感觉信息的连接机制。特定循环将给出内容，非特定循环将给出上下文。意识将是皮质丘脑共振环传递的特定和非特定 40 Hz 活动总和的最终结果。
The philosophical and biological concepts of consciousness are briefly reviewed, from Aristoteles to Descartes to the modern neurobiologist of the last 15 years. The CRICK's corticothalamic integration view, the Edelman's primary and higher order consciousness concept as well as the Edelman and Tononi's dynamic core concept were discussed. Then the corticothalamic resonance theory by Llinas was reported. Central to Llinas's theory is the existence of electrical intrinsic properties of neurones in the central nervous system that allows them to oscillate at different frequencies and if the membrane properties are suitable also to resonate at specific frequencies. From this oscillation and the neuronal connectivity result the corticothalamic dynamic loops specific and non specific. The dynamic corticothalamic loop of the specific thalamic nuclei connect directly as well as through the inhibitory interneurones in layer 4, with the pyramids in layer 5 and 6. The pyramids's rhythmic discharge excite the thalamic specific neurones and indirectly through the reticular neurones a rebound burst is also generated in the specific relay neurones. The oscillatory properties of cortical inhibitory interneurones initiates the action of the recurrent circuit whose function is to inform the cerebral cortex of the content of the sensory pathways. On the other side, the thalamocortical resonant loops of the non especific nuclei, particularly the intralaminar, connect with theapical dendrites of layer 1 pyramids whose discharge go to the thalamic relay neurones directly and through the reticular nucleus. The clinical and MEG data are consistent with the suggestion that the intralaminar nucleus works as providing the binding signal to the sensory specif le information conveyed by the specific pathways. In this way the non specific corticothalamic loop would act as the conjunction mechanism along the dendritic apical shaft with the specific sensory information. The specific loop will give the content and the non specific loop the context. Conciousness would be the final result of the summation of specific and non specific 40 Hz activity conveyed by the resonant corticothalamic loops.