Department of Biomedical Engineering, Duke University, Durham, NC 27708-0281, USA.
Clin Neurophysiol. 2012 Jan;123(1):160-72. doi: 10.1016/j.clinph.2011.06.005. Epub 2011 Jul 19.
The aim of this study was to determine the effects of electrode placement, geometry, and polarity during epidural cortical stimulation (ECS) on thresholds for direct activation of cortical neurons.
We used a computational model of epidural electrical stimulation of the motor cortex coupled to compartmental models of cortical neurons.
Thresholds varied with stimulation polarity and neuron position, and neurons deep within the sulci had much larger thresholds than those on the crowns or lips of the gyri. Axons were more excitable than cell bodies or dendrites. Delivering stimulation with the lead placed above or perpendicular to the sulci resulted in substantial stimulation of the gyri adjacent to the target gyrus. Electrode diameter and inter-electrode spacing influenced thresholds and affected the spread of activation in the cortex.
Electrode placement, geometry, and polarity during ECS influence excitation properties of cortical neurons substantially.
Epidural leads have varying geometries, and in clinical studies of ECS the placement of the lead has been inconsistent. These results provide an improved understanding of the effects of electrode placement, geometry, and polarity on the outcome of ECS and can facilitate the rational implantation and programming of ECS systems.
本研究旨在确定在硬膜外皮层刺激（ECS）期间电极放置、几何形状和极性对皮层神经元直接激活阈值的影响。
我们使用了一种运动皮层硬膜外电刺激的计算模型，该模型与皮层神经元的室模型相结合。
阈值随刺激极性和神经元位置而变化，且位于脑沟深部的神经元的阈值比位于脑回冠部或脑回唇部的神经元的阈值大得多。轴突比胞体或树突更易兴奋。与将导联置于脑沟上方或垂直于脑沟的方式相比，使用位于目标脑回上方或垂直于脑沟的导联进行刺激会导致相邻脑回的显著刺激。电极直径和电极之间的间距会影响阈值，并影响皮层的激活扩散。
在 ECS 期间，电极放置、几何形状和极性会极大地影响皮层神经元的兴奋特性。
硬膜外导联具有不同的几何形状，并且在 ECS 的临床研究中，导联的放置一直不一致。这些结果提供了对电极放置、几何形状和极性对 ECS 结果影响的更好理解，并可以促进 ECS 系统的合理植入和编程。
