Makarova Julia, Toledano Rafael, Blázquez-Llorca Lidia, Sánchez-Herráez Erika, Gil-Nagel Antonio, DeFelipe Javier, Herreras Oscar
Translational Neuroscience, Cajal Institute - CSIC, Madrid 28002, Spain.
Hospital Ruber International, Madrid 28034, Spain.
J Neurosci. 2025 Jan 1;45(1):e0695242024. doi: 10.1523/JNEUROSCI.0695-24.2024.
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 coactive 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.
颅内电位被用作神经网络的功能生物标志物。随着电位从源群体传播开来，它们在记录中会相互混合。在人类中，皮质脑回结构的个体差异带来了额外的挑战，因为功能区域在位置和范围上各不相同。我们使用源分离技术来解开通过植入不同性别的癫痫患者的探索性深部阵列获得的混合电位，以了解共同激活源的数量、位置、相对贡献和动态变化。分离出的发生器独特的空间分布使得为每个患者辨别出数十个独立的皮质区域成为可能，即使在癫痫发作期间这些区域的稳定性依然保持，从而能够对数天内和不同状态下的活动进行追踪。通过将这些分布与磁共振成像（MRI）相匹配，我们将每个区域与脑沟和脑回的有限部分相关联，并确定了相应源的局部或远程起源。我们还绘制了跨阵列的源特异性三维覆盖图。平均而言，单个记录位点由相距数厘米的区域中的3 - 5个局部和远处的发生器产生。在癫痫发作期间，13 - 85%的发生器会参与其中，并且会出现一些新的发生器。结果显示，使用原始电位进行位置分配时存在显著偏差，包括在确定癫痫发作起源部位时出现大量假阳性。双极导联法并不能修正这一问题，反而会引入其自身的额外误差。通过这种方式，源分离揭示了人类电位的多源性质和远颅内传播，同时有效地解决了患者特异性的解剖功能皮质差异问题。
