Maximizing Sensory Dynamic Range by Tuning the Cortical State to Criticality
Maximizing Sensory Dynamic Range by Tuning the Cortical State to Criticality
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DOI：
10.1371/journal.pcbi.1004576
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发表时间：
2015-12-01
影响因子：
4.3
通讯作者：
Shew, Woodrow L.
中科院分区：
文献类型：
--
作者：
Gautam, Hari;Hoang, Thanh T.;Shew, Woodrow L.
神经元之间相互作用的调节可以表现为大脑皮层中群体动力学状态的显著变化。皮质状态的这种转变如何影响皮质回路执行的信息处理尚不清楚。在这里，我们进行了实验和计算建模，以确定如何体感动态范围取决于皮层状态。我们使用微电极阵列记录正在进行的和触须刺激诱发的群体尖峰活动在体觉皮层的乌拉坦麻醉大鼠。我们观察到一个连续的不同的皮质状态，在一个极端的人口活动表现出小规模的变化和弱相关性，另一个极端有大规模的波动和强相关性。在实验中，连续体的沿着移动通常是自然发生的，无需直接操作。此外，在实验和模型中，我们通过操纵抑制性突触相互作用来直接调节皮质状态。我们的主要发现是，体感动态范围在特定的皮质状态下最大化，称为临界状态，接近连续体两端之间的临界点。最佳皮质状态的独特特点是无标度的持续人口动态和适度的相关性，符合理论预测的临界性。然而，为了重现我们的实验结果，我们发现现有的理论需要修改，以解释活动依赖性抑郁症。总之，我们的实验表明，在体内的感觉动态范围是最大限度地接近临界和我们的模型揭示了一个意想不到的作用，活动依赖性抑郁症在这个基本原则的皮质功能。
Modulation of interactions among neurons can manifest as dramatic changes in the state of population dynamics in cerebral cortex. How such transitions in cortical state impact the information processing performed by cortical circuits is not clear. Here we performed experiments and computational modeling to determine how somatosensory dynamic range depends on cortical state. We used microelectrode arrays to record ongoing and whisker stimulus-evoked population spiking activity in somatosensory cortex of urethane anesthetized rats. We observed a continuum of different cortical states; at one extreme population activity exhibited small scale variability and was weakly correlated, the other extreme had large scale fluctuations and strong correlations. In experiments, shifts along the continuum often occurred naturally, without direct manipulation. In addition, in both the experiment and the model we directly tuned the cortical state by manipulating inhibitory synaptic interactions. Our principal finding was that somatosensory dynamic range was maximized in a specific cortical state, called criticality, near the tipping point midway between the ends of the continuum. The optimal cortical state was uniquely characterized by scale-free ongoing population dynamics and moderate correlations, in line with theoretical predictions about criticality. However, to reproduce our experimental findings, we found that existing theory required modifications which account for activity-dependent depression. In conclusion, our experiments indicate that in vivo sensory dynamic range is maximized near criticality and our model revealed an unanticipated role for activity-dependent depression in this basic principle of cortical function.