Kramer Daniel R, Kellis Spencer, Barbaro Michael, Salas Michelle Armenta, Nune George, Liu Charles Y, Andersen Richard A, Lee Brian
Department of Neurosurgery, University of Southern California, Los Angeles, CA, USA.
Department of Neurosurgery, University of Southern California, Los Angeles, CA, USA; Department of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA; Tianqiao and Chrissy Chen Brain-machine Interface Center, California Institute of Technology, Pasadena, CA, USA.
J Clin Neurosci. 2019 May;63:116-121. doi: 10.1016/j.jocn.2019.01.027. Epub 2019 Jan 31.
Somatosensory feedback is the next step in brain computer interface (BCI). Here, we compare three cortical stimulating array modalities for generating somatosensory percepts in BCI. We compared human subjects with either a 64-channel "mini"-electrocorticography grid (mECoG; 1.2-mm diameter exposed contacts with 3-mm spacing, N = 1) over the hand area of primary somatosensory cortex (S1), or a standard grid (sECoG; 1.5-mm diameter exposed contacts with 1-cm spacing, N = 1), to generate artificial somatosensation through direct electrical cortical stimulation. Finally, we reference data in the literature from a patient implanted with microelectrode arrays (MEA) placed in the S1 hand area. We compare stimulation results to assess coverage and specificity of the artificial percepts in the hand. Using the mECoG array, hand mapping revealed coverage of 41.7% of the hand area versus 100% for the sECoG array, and 18.8% for the MEA. On average, stimulation of a single electrode corresponded to sensation reported in 4.42 boxes (range 1-11 boxes) for the mECoG array, 19.11 boxes (range 4-48 boxes) for the sECoG grid, and 2.3 boxes (range 1-5 boxes) for the MEA. Sensation in any box, on average, corresponded to stimulation from 2.65 electrodes (range 1-5 electrodes) for the mECoG grid, 3.58 electrodes for the sECoG grid (range 2-4 electrodes), and 11.22 electrodes (range 2-17 electrodes) for the MEA. Based on these findings, we conclude that mECoG grids provide an excellent balance between spatial cortical coverage of the hand area of S1 and high-density resolution.
体感反馈是脑机接口（BCI）的下一步发展方向。在此，我们比较了三种皮质刺激阵列模式，以在BCI中产生体感感知。我们将人类受试者与放置在初级体感皮层（S1）手部区域的64通道“微型”脑电皮层电图网格（mECoG；直径1.2毫米的暴露触点，间距3毫米，N = 1）或标准网格（sECoG；直径1.5毫米的暴露触点，间距1厘米，N = 1）进行比较，通过直接皮层电刺激来产生人工体感。最后，我们参考了文献中一位在S1手部区域植入微电极阵列（MEA）的患者的数据。我们比较刺激结果，以评估手部人工感知的覆盖范围和特异性。使用mECoG阵列，手部映射显示手部区域的覆盖范围为41.7%，而sECoG阵列的覆盖范围为100%，MEA的覆盖范围为18.8%。平均而言，对于mECoG阵列，单个电极的刺激对应于4.42个方格（范围为1 - 11个方格）报告的感觉，对于sECoG网格为19.11个方格（范围为4 - 48个方格），对于MEA为2.3个方格（范围为1 - 5个方格）。平均而言，任何一个方格中的感觉对应于mECoG网格中2.65个电极（范围为1 - 5个电极）的刺激，sECoG网格为3.58个电极（范围为2 - 4个电极），MEA为11.22个电极（范围为2 - 17个电极）。基于这些发现，我们得出结论，mECoG网格在S1手部区域的空间皮层覆盖范围和高密度分辨率之间提供了出色的平衡。
