Intra-day signal instabilities affect decoding performance in an intracortical neural interface system.
Intra-day signal instabilities affect decoding performance in an intracortical neural interface system.
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DOI：
10.1088/1741-2560/10/3/036004
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发表时间：
2013-06
影响因子：
4
通讯作者：
Hochberg LR
中科院分区：
文献类型：
--
作者：
Perge JA;Homer ML;Malik WQ;Cash S;Eskandar E;Friehs G;Donoghue JP;Hochberg LR
运动神经接口系统 (NIS) 旨在将神经信号转换为运动假肢或辅助设备控制，使瘫痪患者能够重新获得运动或对周围环境的控制。如果记录的神经信号和预期运动行为之间的关系发生变化，效应器或假肢的控制可能会降低。因此，表征信号变异性的生物和技术来源对于可靠的 NIS 非常重要。为了解决基于尖峰的 NIS 中神经信号变异的频率和原因，我们分析了植入三名四肢瘫痪患者运动皮层中的硅微电极阵列记录的尖峰活动和动作电位振幅的日内波动（BrainGate 试点临床试验，IDE）。 84% 的记录单元在单个会话中执行的任务的几分钟周期内显示出表观放电频率（3.8±8.71Hz 或平均速率的 49%）具有统计学上的显着变化，并且 74% 的单元显示尖峰幅度的显着变化（3.7±6.5μV 或平均尖峰幅度的 5.5%）。百分之四十的记录会话显示电极间振幅变化的发生存在显着相关性，表明阵列存在微移动。尽管振幅变化相对频繁，但观察到的日内速率变化中只有 15% 源自尖峰振幅变化或电噪声等记录伪影，而 85% 的速率变化很可能来自生理机制。计算机模拟证实，单个神经元的系统速率变化可能会在解码的神经光标运动中产生方向“偏差”。表观神经元尖峰率的不稳定性确实在参与者光标控制的所有表现评估中的 56% 中产生了方向性偏差（n=2 名参与者，两年内进行了 108 次和 20 次评估），导致这些会话中的表现不佳。我们预计，能够适应所报告的不稳定性的信号采集和解码方法将进一步提高基于皮质内的 NIS 的性能。
Motor Neural Interface Systems (NIS) aim to convert neural signals into motor prosthetic or assistive device control, allowing people with paralysis to regain movement or control over their immediate environment. Effector or prosthetic control can degrade if the relationship between recorded neural signals and intended motor behavior changes. Therefore, characterizing both biological and technological sources of signal variability is important for a reliable NIS. To address the frequency and causes of neural signal variability in a spike-based NIS, we analyzed within-day fluctuations in spiking activity and action potential amplitude recorded with silicon microelectrode arrays implanted in the motor cortex of three people with tetraplegia (BrainGate pilot clinical trial, IDE). Eighty-four percent of the recorded units showed a statistically significant change in apparent firing rate (3.8±8.71Hz or 49% of the mean rate) across several-minute epochs of tasks performed on a single session, and seventy-four percent of the units showed a significant change in spike amplitude (3.7±6.5μV or 5.5% of mean spike amplitude). Forty percent of the recording sessions showed a significant correlation in the occurrence of amplitude changes across electrodes, suggesting array micro-movement. Despite the relatively frequent amplitude changes, only 15% of the observed within-day rate changes originated from recording artifacts such as spike amplitude change or electrical noise, while 85% of the rate changes most likely emerged from physiological mechanisms. Computer simulations confirmed that systematic rate changes of individual neurons could produce a directional “bias” in the decoded neural cursor movements. Instability in apparent neuronal spike rates indeed yielded a directional bias in fifty-six percent of all performance assessments in participant cursor control (n=2 participants, 108 and 20 assessments over two years), resulting in suboptimal performance in these sessions. We anticipate that signal acquisition and decoding methods that can adapt to the reported instabilities will further improve the performance of intracortically-based NISs.
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影响因子：
4
作者：
Chestek CA;Gilja V;Nuyujukian P;Foster JD;Fan JM;Kaufman MT;Churchland MM;Rivera-Alvidrez Z;Cunningham JP;Ryu SI;Shenoy KV
通讯作者：
Shenoy KV
影响因子：
2.5
作者：
Flint, Robert D.;Ethier, Christian;Slutzky, Marc W.
通讯作者：
Slutzky, Marc W.
影响因子：
2.5
作者：
Csicsvari, J;Henze, DA;Buzsáki, G
通讯作者：
Buzsáki, G
影响因子：
9.8
作者：
Ganguly K;Carmena JM
通讯作者：
Carmena JM
影响因子：
4
作者：
Flint RD;Lindberg EW;Jordan LR;Miller LE;Slutzky MW
通讯作者：
Slutzky MW