HermesB: A continuous neural recording system for freely behaving primates
HermesB: A continuous neural recording system for freely behaving primates
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DOI：
10.1109/tbme.2007.895753
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发表时间：
2007-11-01
影响因子：
4.6
通讯作者：
Shenoy, Krishna V.
中科院分区：
文献类型：
--
作者：
Santhanam, Gopal;Linderman, Michael D.;Shenoy, Krishna V.
长期植入的电极阵列使基础电生理学和神经修复学取得了广泛的进步。这些成功激发了新的实验，特别是开发原型植入式假肢处理器，以便在自由行为的受试者（猴子和人类）中持续使用。然而，传统的实验技术要求受试者受到限制，限制了实验的类型和持续时间。在本文中，我们提出了一种双通道、电池供电的神经记录系统，带有集成的三轴加速度计，可与自由行为的灵长类动物中长期植入的电极阵列一起使用。名为 HermesB 的记录系统是独立的、自主的、可编程的，能够将宽带神经（以 30 kS/s 采样）和加速度数据记录到可移动紧凑型闪存卡上长达 48 小时。我们使用 HermesB 从成年猕猴那里收集了长期数据集，这些数据集提供了对传统实验中无法获得的时间尺度和自由行为的洞察。在一系列时间尺度内观察到动作电位形状和均方根 (RMS) 噪声的变化。动作电位的峰间电压在 24 小时内变化高达 30%，其中包括与头部高速运动同时发生的波形幅度的阶跃变化（高达 25%）。这些初步结果表明尖峰排序算法不能再假设稳定的神经信号，并且需要过渡到自适应信号处理方法以最大限度地提高性能。在身体活动期间（由头戴式加速度计定义），观察到 5-25 Hz 局部场电位 (LFP) 功率显着降低，放电频率变异性增加。使用适合 LFP 功率的阈值，403 个 5 分钟记录块中的 93% 被正确分类为活动或非活动，这可能为识别假肢应用中的不同行为环境提供有效的工具。这些结果证明了 HermesB 系统的实用性，并激励使用此类系统来推进神经修复和电生理学实验。
Chronically implanted electrode arrays have enabled a broad range of advances in basic electrophysiology and neural prosthetics. Those successes motivate new experiments, particularly, the development of prototype implantable prosthetic processors for continuous use in freely behaving subjects, both monkeys and humans. However, traditional experimental techniques require the subject to be restrained, limiting both the types and duration of experiments. In this paper, we present a dual-channel, battery-powered neural recording system with an integrated three-axis accelerometer for use with chronically implanted electrode arrays in freely behaving primates. The recording system called HermesB, is self-contained, autonomous, programmable, and capable of recording broadband neural (sampled at 30 kS/s) and acceleration data to a removable compact flash card for up to 48 h. We have collected long-duration data sets with HermesB from an adult macaque monkey which provide insight into time scales and free behaviors inaccessible under traditional experiments. Variations in action potential shape and root-mean square (RMS) noise are observed across a range of time scales. The peak-to-peak voltage of action potentials varied by up to 30% over a 24-h period including step changes in waveform amplitude (up to 25%) coincident with high acceleration movements of the head. These initial results suggest that spike-sorting algorithms can no longer assume stable neural signals and will need to transition to adaptive signal processing methodologies to maximize performance. During physically active periods (defined by head-mounted accelerometer), significantly reduced 5-25-Hz local field potential (LFP) power and increased firing rate variability were observed. Using a threshold fit to LFP power, 93% of 403 5-min recording blocks were correctly classified as active or inactive, potentially providing an efficient tool for identifying different behavioral contexts in prosthetic applications. These results demonstrate the utility of the HermesB system and motivate using this type of system to advance neural prosthetics and electrophysiological experiments.