Sotiropoulos Stamatios N, Steinmetz Peter N
Brain Modeling Laboratory, Harrington Department of Bioengineering, Mail Code 9709, ASU Main Campus, Tempe, AZ 85287, USA.
J Neural Eng. 2007 Jun;4(2):107-19. doi: 10.1088/1741-2560/4/2/011. Epub 2007 Mar 28.
To better understand the spatial extent of the direct effects of deep brain stimulation (DBS) on neurons, we implemented a geometrically realistic finite element electrical model incorporating anisotropic and inhomogenous conductivities. The model included the subthalamic nucleus (STN), substantia nigra (SN), zona incerta (ZI), fields of Forel H2 (FF), internal capsule (IC) and Medtronic 3387/3389 electrode. To quantify the effects of stimulation, we extended previous studies by using multi-compartment axon models with geometry and orientation consistent with anatomical features of the brain regions of interest. Simulation of axonal firing produced a map of relative changes in axonal activation. Voltage-controlled stimulation, with clinically typical parameters at the dorso-lateral STN, caused axon activation up to 4 mm from the target. This activation occurred within the FF, IC, SN and ZI with current intensities close to the average injected during DBS (3 mA). A sensitivity analysis of model parameters (fiber size, fiber orientation, degree of inhomogeneity, degree of anisotropy, electrode configuration) revealed that the FF and IC were consistently activated. Direct activation of axons outside the STN suggests that other brain regions may be involved in the beneficial effects of DBS when treating Parkinsonian symptoms.
为了更好地理解深部脑刺激（DBS）对神经元的直接影响的空间范围，我们构建了一个包含各向异性和非均匀电导率的几何逼真的有限元电模型。该模型包括丘脑底核（STN）、黑质（SN）、未定带（ZI）、Forel H2区（FF）、内囊（IC）和美敦力3387/3389电极。为了量化刺激的效果，我们通过使用多室轴突模型扩展了先前的研究，该模型的几何形状和方向与感兴趣的脑区的解剖特征一致。轴突发火的模拟产生了轴突激活相对变化的图谱。在背外侧STN使用临床典型参数进行电压控制刺激，导致距靶点4毫米范围内的轴突激活。这种激活发生在FF、IC、SN和ZI内，电流强度接近DBS期间注入的平均值（3 mA）。对模型参数（纤维大小、纤维方向、非均匀程度、各向异性程度、电极配置）的敏感性分析表明，FF和IC持续被激活。STN以外的轴突直接激活表明，在治疗帕金森症状时，其他脑区可能参与了DBS的有益效果。
