Mapping of primary somatosensory cortex of the hand area using a high-density electrocorticography grid for closed-loop brain computer interface
Mapping of primary somatosensory cortex of the hand area using a high-density electrocorticography grid for closed-loop brain computer interface
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DOI：
10.1088/1741-2552/ab7c8e
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发表时间：
2021-06-01
影响因子：
4
通讯作者：
Lee, Brian
中科院分区：
文献类型：
--
作者：
Kramer, Daniel R.;Lee, Morgan B.;Lee, Brian
目标。在感觉运动脑机接口(BCI)中产生感觉的理想模式尚未确定。在这里，我们报告了在体感脑机接口系统中使用高密度“迷你”皮质脑电(MECoG)网格的可行性。接近。对13例顽固性癫痫患者进行了标准硬膜下电极的临床植入，用于癫痫的定位。在初级躯体感觉皮质的手部区域放置额外的高密度mECoG栅格(Adtech，8×8，暴露1.2 mm，中心到中心间距3 mm)。植入后进行皮层标测，刺激参数为：频率：50 Hz，脉宽：250mU S，脉冲宽度：4 S，极性：交变，电流范围：0.5~12 mA，由癫痫专家自行决定。被唤起的感官知觉的位置被记录下来，并伴随着感觉的描述。这只手被分成48个不同的盒子。如果盒子里的任何地方都有感觉，就包括一个盒子。主要结果。手的覆盖率为63.9%(+/-34.4%)(平均+/-S.D.)。平均冗余度，以电极对刺激同一盒测量，为1.9(+/-2.2)个电极/盒；平均分辨率，测量为11.4(+/-13.7)盒，8.1(+/-10.7)盒在手指和3.4(+/-6.0)盒在手掌。通过量化可用的感知来评估系统的功能效用。在最严格的分类下，平均每个网格有2.8个可用知觉，即皮肤病排他性知觉。考虑到同一解剖位置的“感知上独特的”感知，平均每个网格有5.5个可用感知。意义重大。与微电极系统覆盖面积小、冗余度小或标准皮层脑电网格分辨率低相比，mECoG可能是体感脑机接口系统的最佳模式，具有良好的手覆盖和最小冗余。
Objective. The ideal modality for generating sensation in sensorimotor brain computer interfaces (BCI) has not been determined. Here we report the feasibility of using a high-density 'mini'-electrocorticography (mECoG) grid in a somatosensory BCI system. Approach. Thirteen subjects with intractable epilepsy underwent standard clinical implantation of subdural electrodes for the purpose of seizure localization. An additional high-density mECoG grid was placed (Adtech, 8 by 8, 1.2 mm exposed, 3 mm center-to-center spacing) over the hand area of primary somatosensory cortex. Following implantation, cortical mapping was performed with stimulation parameters of frequency: 50 Hz, pulse-width: 250 mu s, pulse duration: 4 s, polarity: alternating, and current that ranged from 0.5 mA to 12 mA at the discretion of the epileptologist. Location of the evoked sensory percepts was recorded along with a description of the sensation. The hand was partitioned into 48 distinct boxes. A box was included if sensation was felt anywhere within the box. Main results. The percentage of the hand covered was 63.9% (+/- 34.4%) (mean +/- s.d.). Mean redundancy, measured as electrode pairs stimulating the same box, was 1.9 (+/- 2.2) electrodes per box; and mean resolution, measured as boxes included per electrode pair stimulation, was 11.4 (+/- 13.7) boxes with 8.1 (+/- 10.7) boxes in the digits and 3.4 (+/- 6.0) boxes in the palm. Functional utility of the system was assessed by quantifying usable percepts. Under the strictest classification, 'dermatomally exclusive' percepts, the mean was 2.8 usable percepts per grid. Allowing 'perceptually unique' percepts at the same anatomical location, the mean was 5.5 usable percepts per grid. Significance. Compared to the small area of coverage and redundancy of a microelectrode system, or the poor resolution of a standard ECoG grid, a mECoG is likely the best modality for a somatosensory BCI system with good coverage of the hand and minimal redundancy.