Department of Physics, Indiana University, Bloomington, Indiana 47405, USA.
Department of Mathematical Sciences, Indiana University-Purdue University, Indianapolis, Indiana 46202, USA.
Phys Rev Lett. 2021 Mar 5;126(9):098101. doi: 10.1103/PhysRevLett.126.098101.
Much evidence seems to suggest the cortex operates near a critical point, yet a single set of exponents defining its universality class has not been found. In fact, when critical exponents are estimated from data, they widely differ across species, individuals of the same species, and even over time, or depending on stimulus. Interestingly, these exponents still approximately hold to a dynamical scaling relation. Here we show that the theory of quasicriticality, an organizing principle for brain dynamics, can account for this paradoxical situation. As external stimuli drive the cortex, quasicriticality predicts a departure from criticality along a Widom line with exponents that decrease in absolute value, while still holding approximately to a dynamical scaling relation. We use simulations and experimental data to confirm these predictions and describe new ones that could be tested soon.
大量证据似乎表明皮质在临界点附近运作，但尚未找到一组确定其普遍性类的指数。事实上，当从数据中估计临界指数时，它们在不同物种、同一物种的个体甚至在不同时间或取决于刺激时，差异很大。有趣的是，这些指数仍然大致符合动态缩放关系。在这里，我们表明，准临界性理论是大脑动力学的组织原则，可以解释这种自相矛盾的情况。当外部刺激驱动皮质时，准临界性预测会沿着 Widom 线偏离临界状态，其指数的绝对值减小，但仍然大致符合动态缩放关系。我们使用模拟和实验数据来验证这些预测，并描述了一些新的预测，这些预测很快就可以进行测试。
