Department of Biomedical Engineering, Duke University, Durham, NC, United States.
Department of Biomedical Engineering, Duke University, Durham, NC, United States; Department of Electrical and Computer Engineering, Duke University, Durham, NC, United States; Department of Neurobiology, Duke University, Durham, NC, United States; Department of Neurosurgery, Duke University, Durham, NC, United States.
Clin Neurophysiol. 2023 Jan;145:26-35. doi: 10.1016/j.clinph.2022.11.002. Epub 2022 Nov 9.
To determine whether dipoles are an appropriate simplified representation of neural sources for stereo-EEG (sEEG).
We compared the distributions of voltages generated by a dipole, biophysically realistic cortical neuron models, and extended regions of cortex to determine how well a dipole represented neural sources at different spatial scales and at electrode to neuron distances relevant for sEEG. We also quantified errors introduced by the dipole approximation of neural sources in sEEG source localization using standardized low-resolution electrotomography (sLORETA).
For pyramidal neurons, the coefficient of correlation between voltages generated by a dipole and neuron model were > 0.9 for distances > 1 mm. For small regions of cortex (∼0.1 cm), the error in voltages between a dipole and region was < 100 µV for all distances. However, larger regions of active cortex (>5 cm) yielded > 50 µV errors within 1.5 cm of an electrode when compared to single dipoles. Finally, source localization errors were < 5 mm when using dipoles to represent realistic neural sources.
Single dipoles are an appropriate source model to represent both single neurons and small regions of active cortex, while multiple dipoles are required to represent large regions of cortex.
Dipoles are computationally tractable and valid source models for sEEG.
确定偶极子是否是立体脑电图（sEEG）神经源的合适简化表示。
我们比较了偶极子、生物物理上逼真的皮质神经元模型和扩展的皮质区域产生的电压分布，以确定偶极子在不同空间尺度和与 sEEG 相关的电极到神经元距离下如何很好地表示神经源。我们还通过标准化低分辨率电层析成像（sLORETA）量化了 sEEG 源定位中神经源的偶极子近似引入的误差。
对于锥形神经元，偶极子和神经元模型产生的电压之间的相关系数>0.9，距离>1mm。对于小的皮质区域（约 0.1cm），对于所有距离，偶极子和区域之间的电压误差<100µV。然而，与单个偶极子相比，当比较到距离电极 1.5cm 内的活跃皮质较大区域（>5cm）时，会产生>50µV 的误差。最后，使用偶极子表示实际神经源时，源定位误差<5mm。
单偶极子是表示单个神经元和小的活跃皮质区域的合适源模型，而多个偶极子则需要表示大的皮质区域。
偶极子是 sEEG 的计算上可行且有效的源模型。
