Event-related fields of the magnetoencephalogram are triggered by sensory stimuli and appear as a series of waves extending hundreds of milliseconds after stimulus onset. They reflect the processing of the stimulus in cortex and have a highly subject-specific morphology. However, we still have an incomplete picture of how event-related fields are generated, what the various waves signify, and why they are so subject-specific. Here, we focus on this problem through the lens of a computational model which describes auditory cortex in terms of interconnected cortical columns as part of hierarchically placed fields of the core, belt, and parabelt areas. We develop an analytical approach arriving at solutions to the system dynamics in terms of normal modes: damped harmonic oscillators emerging out of the coupled excitation and inhibition in the system. Each normal mode is a global feature which depends on the anatomical structure of the entire auditory cortex. Further, normal modes are fundamental dynamical building blocks, in that the activity of each cortical column represents a combination of all normal modes. This approach allows us to replicate a typical auditory event-related response as a weighted sum of the single-column activities. Our work offers an alternative to the view that the event-related field arises out of spatially discrete, local generators. Rather, there is only a single generator process distributed over the entire network of the auditory cortex. We present predictions for testing to what degree subject-specificity is due to cross-subject variations in dynamical parameters rather than in the cortical surface morphology.

中文翻译：

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通过封装听觉皮层解剖结构的机械模型解释与事件相关的场。

脑波的与事件相关的场由感觉刺激触发，并在刺激发作后以一系列延伸数百毫秒的波的形式出现。它们反映了皮层中刺激的处理，并具有高度特定于受试者的形态。但是，对于事件相关字段的生成方式，各种波的含义以及它们为何如此具有特定主题，我们仍然不完整。在这里，我们通过计算模型的角度来关注这个问题，该模型以相互连接的皮质柱作为核心，皮带和副带区域的分层放置字段的一部分来描述听觉皮质。我们开发一种分析方法，以常规模式解决系统动力学问题：阻尼谐波振荡器从系统中的耦合激励和抑制中脱颖而出。每个正常模式都是一个全局特征，它取决于整个听觉皮层的解剖结构。此外，正常模式是基本的动态构建块，因为每个皮层柱的活动表示所有正常模式的组合。这种方法使我们能够将典型的与听觉事件相关的反应复制为单列活动的加权总和。我们的工作提供了另一种观点，即与事件相关的字段源自空间离散的本地生成器。相反，只有单个生成器过程分布在听觉皮层的整个网络上。我们提出了预测，以测试受试者特异性在多大程度上是由于动态参数而不是皮质表面形态的跨学科变化所致。