Aix Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille 13005, France.
Aix Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille 13005, France; APHM, Timone Hospital, Epileptology and cerebral rhythmology, Marseille 13005, France.
Neuroimage. 2023 Apr 1;269:119905. doi: 10.1016/j.neuroimage.2023.119905. Epub 2023 Jan 28.
Stereo-electroencephalography (SEEG) is the surgical implantation of electrodes in the brain to better localize the epileptic network in pharmaco-resistant epileptic patients. This technique has exquisite spatial and temporal resolution. Still, the number and the position of the electrodes in the brain is limited and determined by the semiology and/or preliminary non-invasive examinations, leading to a large number of unexplored brain structures in each patient. Here, we propose a new approach to reconstruct the activity of non-sampled structures in SEEG, based on independent component analysis (ICA) and dipole source localization. We have tested this approach with an auditory stimulation dataset in ten patients. The activity directly recorded from the auditory cortex served as ground truth and was compared to the ICA applied on all non-auditory electrodes. Our results show that the activity from the auditory cortex can be reconstructed at the single trial level from contacts as far as ∼40 mm from the source. Importantly, this reconstructed activity is localized via dipole fitting in the proximity of the original source. In addition, we show that the size of the confidence interval of the dipole fitting is a good indicator of the reliability of the result, which depends on the geometry of the SEEG implantation. Overall, our approach allows reconstructing the activity of structures far from the electrode locations, partially overcoming the spatial sampling limitation of intracerebral recordings.
立体脑电图（SEEG）是将电极植入大脑，以更好地定位药物抵抗性癫痫患者的癫痫网络。这项技术具有精细的时空分辨率。然而，大脑中电极的数量和位置是有限的，由症状学和/或初步的非侵入性检查决定，导致每个患者都有大量未被探索的大脑结构。在这里，我们提出了一种基于独立成分分析（ICA）和偶极子源定位的新方法，用于重建 SEEG 中非采样结构的活动。我们已经在 10 名患者的听觉刺激数据集上测试了这种方法。直接从听觉皮层记录的活动作为真实值，并与所有非听觉电极上应用的 ICA 进行比较。我们的结果表明，从距离源最远约 40mm 的触点可以在单次试验水平上重建听觉皮层的活动。重要的是，通过在原始源附近进行偶极子拟合，可以对重建的活动进行定位。此外，我们还表明，偶极子拟合置信区间的大小是结果可靠性的良好指标，这取决于颅内记录的植入几何形状。总体而言，我们的方法允许重建远离电极位置的结构的活动，部分克服了脑内记录的空间采样限制。
