Rhythmic activity in the brain fluctuates with behaviour and cognitive state, through a combination of coexisting and interacting frequencies. At large spatial scales such as those studied in human M/EEG, measured oscillatory dynamics are believed to arise primarily from a combination of cortical (intracolumnar) and corticothalamic rhythmogenic mechanisms. Whilst considerable progress has been made in characterizing these two types of neural circuit separately, relatively little work has been done that attempts to unify them into a single consistent picture. This is the aim of the present paper. We present and examine a whole-brain, connectome-based neural mass model with detailed long-range cortico-cortical connectivity and strong, recurrent corticothalamic circuitry. This system reproduces a variety of known features of human M/EEG recordings, including spectral peaks at canonical frequencies, and functional connectivity structure that is shaped by the underlying anatomical connectivity. Importantly, our model is able to capture state- (e.g., idling/active) dependent fluctuations in oscillatory activity and the coexistence of multiple oscillatory phenomena, as well as frequency-specific modulation of functional connectivity. We find that increasing the level of sensory drive to the thalamus triggers a suppression of the dominant low frequency rhythms generated by corticothalamic loops, and subsequent disinhibition of higher frequency endogenous rhythmic behaviour of intracolumnar microcircuits. These combine to yield simultaneous decreases in lower frequency and increases in higher frequency components of the M/EEG power spectrum during states of high sensory or cognitive drive. Building on this, we also explored the effect of pulsatile brain stimulation on ongoing oscillatory activity, and evaluated the impact of coexistent frequencies and state-dependent fluctuations on the response of cortical networks. Our results provide new insight into the role played by cortical and corticothalamic circuits in shaping intrinsic brain rhythms, and suggest new directions for brain stimulation therapies aimed at state-and frequency-specific control of oscillatory brain activity.

中文翻译：

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基于连接组的皮质丘脑节律神经活动和连接的状态和刺激依赖性调节模型

通过共存和相互作用的频率的组合，大脑中的节律活动随着行为和认知状态而波动。在大空间尺度上，例如在人类脑电图研究中，测量到的振荡动力学被认为主要是由皮质（柱内）和皮质丘脑节律机制的组合产生的。虽然在分别表征这两种类型的神经回路方面已经取得了相当大的进展，但尝试将它们统一成单一一致图像的工作相对较少。这就是本文的目的。我们提出并检查了一个全脑、基于连接组的神经质量模型，具有详细的远程皮质-皮质连接和强大的、循环的皮质丘脑回路。该系统再现了人类 M/EEG 记录的各种已知特征，包括规范频率的频谱峰值，以及由底层解剖连接形成的功能连接结构。重要的是，我们的模型能够捕获振荡活动中的状态（例如，空闲/活动）相关波动和多种振荡现象的共存，以及功能连接的频率特定调制。我们发现，增加丘脑的感觉驱动水平会触发对皮质丘脑环路产生的主导低频节律的抑制，以及随后对柱内微电路的高频内源节律行为的去抑制。在高感觉或认知驱动状态期间，这些结合在一起会产生 M/EEG 功率谱的低频分量同时减少和高频分量增加。在此基础上，我们还探讨了脉动脑刺激对持续振荡活动的影响，并评估了共存频率和状态依赖性波动对皮质网络响应的影响。我们的研究结果为皮质和皮质丘脑回路在塑造内在大脑节律中所发挥的作用提供了新的见解，并为旨在对大脑振荡活动进行状态和频率特异性控制的脑刺激疗法提出了新方向。