Intracranial potentials are used as functional biomarkers of neural networks. As potentials spread away from the source populations, they become mixed in the recordings. In humans, interindividual differences in the gyral architecture of the cortex pose an additional challenge, as functional areas vary in location and extent. We used source separation techniques to disentangle mixing potentials obtained by exploratory deep arrays implanted in epileptic patients of either sex to gain access to the number, location, relative contribution and dynamics of co-active sources. The unique spatial profiles of separated generators made it possible to discern dozens of independent cortical areas for each patient, whose stability maintained even during seizure, enabling the follow up of activity for days and across states. Through matching these profiles to MRI, we associated each with limited portions of sulci and gyri, and determined the local or remote origin of the corresponding sources. We also plotted source-specific 3D coverage across arrays. In average, individual recording sites are contributed to by 3-5 local and distant generators from areas up to several centimeters apart. During seizure, 13-85 % of generators were involved, and a few appeared anew. Significant bias in location assignment using raw potentials is revealed, including numerous false positives when determining the site of origin of a seizure. This is not amended by bipolar montage, which introduce additional errors of its own. In this way, source disentangling reveals the multisource nature and far intracranial spread of potentials in humans, while efficiently addressing patient-specific anatomofunctional cortical divergence.Significance Statement Field potentials are used to better localize zones showing normal and pathological activity. However, as potentials spread throughout the brain volume, they mix with others and make their place of origin uncertain, even when recorded intracranially. We used advanced algorithms to disentangle the activity of each these zones by their unique spatial profiles, which allowed us to determine the 3D outline of normal and epileptic areas and follow their activity for days. Dozens of independent sources per patient can be explored and precisely located. The findings show that standard stereoEEG recordings are contributed by 3-5 populations, which after separation will help to plan clinical intervention to break epileptic networks by more accurately marking epileptic foci and avoiding false positives.

中文翻译：

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来自解开的人类深部来源的颅内电压曲线揭示了多源组成和源分配偏差。


颅内电位用作神经网络的功能生物标志物。随着电位从源种群中扩散开来，它们在记录中变得混合。在人类中，皮层脑回结构的个体间差异带来了额外的挑战，因为功能区域的位置和范围各不相同。我们使用源分离技术来解开通过植入任何性别的癫痫患者体内的探索性深度阵列获得的混合电位，以获得共活性源的数量、位置、相对贡献和动态。分离发生器的独特空间轮廓使得能够为每位患者识别数十个独立的皮质区域，即使在癫痫发作期间，其稳定性也保持稳定，从而能够跨状态跟踪数天的活动。通过将这些图谱与 MRI 匹配，我们将每个图谱与脑沟和脑回的有限部分相关联，并确定相应来源的本地或远程来源。我们还绘制了跨阵列的特定源 3D 覆盖率。平均而言，单个记录站点由 3-5 个本地和远距离发电机提供，距离可达几厘米。在癫痫发作期间，涉及 13-85% 的发电机，还有一些重新出现。揭示了使用原始电位的位置分配存在显着偏差，包括在确定癫痫发作起源部位时出现许多假阳性。这没有被双极蒙太奇所修正，它本身就引入了额外的错误。通过这种方式，源解缠揭示了人类电位的多源性质和远颅内扩散，同时有效地解决了患者特异性解剖功能皮质分歧。显著性陈述 场电位用于更好地定位显示正常和病理活动的区域。然而，随着电位扩散到整个脑体积中，它们会与其他电位混合，使它们的原点变得不确定，即使颅内记录也是如此。我们使用先进的算法，通过独特的空间剖面来解开每个区域的活动，这使我们能够确定正常和癫痫区域的 3D 轮廓，并跟踪它们的活动数天。可以探索和精确定位每位患者的数十个独立来源。研究结果表明，标准的立体脑电图记录由 3-5 个人群贡献，分离后将有助于规划临床干预，通过更准确地标记癫痫病灶和避免假阳性来打破癫痫网络。