Ongoing spontaneous activity controls access to consciousness: a neuronal model for inattentional blindness.
Ongoing spontaneous activity controls access to consciousness: a neuronal model for inattentional blindness.
复制标题
DOI：
10.1371/journal.pbio.0030141
复制
发表时间：
2005-05
期刊：
影响因子：
9.8
通讯作者：
中科院分区：
文献类型：
--
作者：
即使在没有感觉输入的情况下，皮质和丘脑神经元也可以表现出持续自发活动的结构化模式，其起源和功能意义尚不清楚。我们使用计算机模拟来探索自发活动从由远程、自上而下的兴奋性轴突连接的多个互连丘脑皮质柱的简化模型中产生的条件，并检查其与刺激诱导的激活的相互作用。模拟有助于表征两种主要的活动状态。首先，自发伽马能带振荡出现在由上行神经调节系统控制的精确阈值处。其次，在自发活动的网络中，我们观察到具有长距离投射的皮层神经元中许多可能的高级活动相干状态之一的突然“点燃”。在这种点燃状态下，自发活动可能会阻碍外部感觉处理。我们将这些特性与对内源性意识状态的神经基础的实验观察联系起来，特别是在“无意盲视”的心理物理现象中发生的意识获取障碍，其中正常受试者强烈地从事心理活动，无法注意到显着但不相关的感官刺激。尽管高度简化，但最小网络的通用属性可能有助于阐明意识自主性背后的一些基本大脑现象。对大脑皮层和丘脑底层活动回路的计算机模拟表明，精确控制的振荡状态可以控制感觉信息的中枢神经处理
Even in the absence of sensory inputs, cortical and thalamic neurons can show structured patterns of ongoing spontaneous activity, whose origins and functional significance are not well understood. We use computer simulations to explore the conditions under which spontaneous activity emerges from a simplified model of multiple interconnected thalamocortical columns linked by long-range, top-down excitatory axons, and to examine its interactions with stimulus-induced activation. Simulations help characterize two main states of activity. First, spontaneous gamma-band oscillations emerge at a precise threshold controlled by ascending neuromodulator systems. Second, within a spontaneously active network, we observe the sudden “ignition” of one out of many possible coherent states of high-level activity amidst cortical neurons with long-distance projections. During such an ignited state, spontaneous activity can block external sensory processing. We relate those properties to experimental observations on the neural bases of endogenous states of consciousness, and particularly the blocking of access to consciousness that occurs in the psychophysical phenomenon of “inattentional blindness,” in which normal subjects intensely engaged in mental activity fail to notice salient but irrelevant sensory stimuli. Although highly simplified, the generic properties of a minimal network may help clarify some of the basic cerebral phenomena underlying the autonomy of consciousness. Computer simulations of the circuits of activity in the cerebral cortex and underlying thalamus suggest that precisely controlled oscillatory states can control the central neural processing of sensory information