Rudolf Magnus Institute of Neuroscience, Dept. of Neurology and Neurosurgery, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
J Neurosci Methods. 2010 Mar 30;187(2):270-9. doi: 10.1016/j.jneumeth.2010.01.019. Epub 2010 Jan 28.
Invasive brain signal recordings generally rely on bioelectrodes implanted on the cortex underneath the dura. Subdural recordings have strong advantages in terms of bandwidth, spatial resolution and signal quality. However, subdural electrodes also have the drawback of compromising the long-term stability of such implants and heighten the risk of infection. Epidurally implanted electrodes might provide a viable alternative to subdural electrodes, offering a compromise between signal quality and invasiveness. Determining the feasibility of epidural electrode implantation for e.g., clinical research, brain-computer interfacing (BCI) and cognitive experiments, requires the characterization of the electrical properties of the dura, and its effect on signal feature detection. In this paper we report measurements of brain signal attenuation by the human dura in vivo. In addition, we use signal detection theory to study how the presence of the dura between the sources and the recording electrodes affects signal power features in motor BCI experiments. For noise levels typical of clinical brain signal recording equipment, we observed no detrimental effects on signal feature detection due to the dura. Subdural recordings were found to be more robust with respect to increased instrumentation noise level as compared to their epidural counterpart nonetheless. Our findings suggest that epidural electrode implantation is a viable alternative to subdural implants from the feature detection viewpoint.
侵入性脑信号记录通常依赖于植入硬脑膜下皮层的生物电极。在带宽、空间分辨率和信号质量方面，硬脑膜下记录具有很强的优势。然而，硬脑膜下电极也存在植入物长期稳定性差和感染风险增加的缺点。硬膜外植入电极可能是硬脑膜下电极的一种可行替代品，在信号质量和侵入性之间提供了一种折衷。例如，为了临床研究、脑机接口 (BCI) 和认知实验，确定硬膜外电极植入的可行性需要对硬脑膜的电特性及其对信号特征检测的影响进行表征。在本文中，我们报告了人体硬脑膜对脑信号衰减的测量。此外，我们使用信号检测理论研究了硬脑膜在源和记录电极之间的存在如何影响运动 BCI 实验中的信号功率特征。对于临床脑信号记录设备中典型的噪声水平，我们没有观察到由于硬脑膜而对信号特征检测产生不利影响。然而，与硬膜外记录相比，硬脑膜下记录在增加仪器噪声水平方面具有更高的稳健性。我们的发现表明，从特征检测的角度来看，硬膜外电极植入是硬脑膜下植入的一种可行替代方案。
