光遗传学无线光刺激器与闭环调控系统研制

	光遗传学无线光刺激器与闭环调控系统研制
其他题名	Wireless Optical Stimulator and Closed-loopModulation System for Optogenetics Research
	袁明军
学位类型	硕士
导师	王守岩
	2015-10
学位授予单位	中国科学院大学
学位专业	光学工程
关键词	光遗传学光刺激器脑电采集调控系统在体验证实验
摘要	光遗传学技术是一种具有精确靶向性，高时空分辨率，毫秒级快速响应等优点的新兴神经调控手段。传统的光遗传调控系统主要是依赖激光器、有线光纤以及电生理记录仪。首先，庞大的激光器和光纤的有线连接限制了自由活动小动物的在体光遗传神经调控研究，尤其是涉及到观察动物大范围行为的情形，这就需要无线控制的微型化光刺激器。其次，随着光遗传技术向智能闭环调控发展，亟需研发集成光刺激和神经电活动记录的调控系统，为闭环策略研究提供支持。因此光调控系统的微型化和无线化对于促进光遗传技术在活体动物神经调控领域的应用具有重要意义。本文针对微型化和无线控制技术需求及在体自由活动和闭环调控研究需求，研制基于uLED 的微型无线程控光刺激器和闭环光刺激-电记录神经调控系统。首先，研制具有多通道输出、微型化、参数无线程控可调等优点的无线程控光刺激器。该刺激器系统包括(1) 上位机软件：采用LabVIEW 图形化语言编写，用于调节刺激参数。(2)无线发送模块：以微控制器nRF51822 为核心，接插在PC 的USB 口，负责将上位机的控制指令无线发送至刺激器。(3) 刺激器：选用集成无线通信模块的微控制器nRF51822，实现系统控制、各模块驱动以及接收上位机控制指令，提高集成度减小尺寸重量。LED 驱动模块选用恒流驱动芯片 MBI5036 实现64 阶亮度调节。(4)植入式神经刺激光极，在其尖端焊接波长460 nm 的蓝光uLED 实现对神经元的光刺激。其次，研制具有集成度高，光刺激-电记录，无线传输，实时处理，存储数据等特点的闭环调控系统。该闭环系统包括(1)上位机软件：采用LabVIEW 编写，用于调节刺激参数，脑电波形显示和数据存储。(2) 无线收发模块：作为上位机与刺激传感模块通信的中间点，与PC 上位机的通信采用芯片CP2102 实现，和刺激传感模块的通信采用nRF24L01。 (3)刺激传感模块：选用STM32F417 芯片作为处理器，主频高达168M，集成DSP 指令，提升实时处理能力；选用TI 公司的24 位8 通道采样的低噪声芯片ADS1299，实现脑电多靶点的电记录检测；选用nRF24L01 传输脑电数据至上位机；LED 驱动模块用MBI5036。(4)集成LED 和记录电极的光电神经接口。最后，将光极埋置到转基因(Thy1-ChR-EYFP)小鼠M2 脑区，完成三个验证实验：对比无线光刺激器与激光器的刺激效应，验证无线光刺激器的重量尺寸适用于自由活动小鼠的行为调控实验，验证闭环调控系统刺激和同步脑电采集存储功能。结果表明：微型无线光刺激器尺寸为20 mm × 16 mm，重3 g，输出光功率1.5 mW~4.5 mW，无线距离10 米，刺激效应与激光器相似，30 Hz 光刺激增强小鼠运动情况，适用于小鼠自由活动的光遗传神经调控实验。闭环系统给予小鼠30Hz 光刺激时以1 kSPS 的采样率记录到与刺激相对应的脑电活动变化。本文针对光遗传学科学实验需求，研制微型无线光刺激器和闭环神经调控系统。系统参数测试和动物在体实验表明两套设备满足光遗传学中激活离子通道和记录脑电信号的要求，且具有微型化、低成本、可扩展等优点，为小动物行为相关的神经调控搭建光遗传学实验平台，有利于促进光遗传技术在小动物在体神经环路研究、疾病模型探索等领域的应用。
其他摘要	Optogenetics has become a novel neuromodulation technology by providing precise stimulation with high spatiotemporal resolution. Traditional research of optogenetics mainly based on laser, fiber and electroencephalogram (EEG) acquisition system. However, these tethered fiber-optic approaches have restricted the applications of the technique on neuromodulation on small freely moving animal in vivo. Moreover, as the trend of modulation related optogenetics developing toward closed-loop control, there was an urgent need for integrated system combining optical simulation and EEG acquisition, which could provide rich data for closed-loop strategy. Thus, this paper presented a miniaturized, wirelessly optical stimulator and a closed-loop system integrating simulation and recording. Firstly, a multi-channel, miniaturized and wirelessly programmed optical stimulator was developed, which consisted of 4 components. (1) Software developed in LabVIEW for adjusting stimulation parameter. (2) A wireless transmitter based on nRF51822 used for connecting software and the stimulator. (3) The stimulator was implemented by nRF51822, an ultra-low power 2.4 GHz wireless system on chip, which was suitable for little data transform and small size model. LED was derived by MBI5036 with 64-order brightness adjustment. (4) An implantable optrode assembled with 460nm uLED for stimulation. Secondly, we developed a closed-loop system combining optical stimulating and EEG recording, to transmit EEG data to software which was then stored on PC. The system was composed of four components. (1) Software for EEG displaying and data storing. (2) Wireless module based on CP2102 and nRF24L01 for connecting software and simulating-sensing module. (3) Stimulating and sensing module developed with high performance MCU STM32F417 was used for controlling other modules, such as EEG acquisition module based on ADS1299, wireless module and LED driving module. (4) Optrode integrated LED and electrode. Finally, we implanted the optrode into the secondary motor cortex of the ChR2 transfected mice to implement three verify experiments. (1) Compared the stimulation effect of laser and this stimulator. (2) Verified the stimulator by the behavior modulation on mice. (3) Confirmed that the closed-loop system was capable of simulating and EEG recording simultaneously. As the results showed, with size of 20 mm×16 mm, weight of 3g, the stimulator could be wirelessly controlled up to 10 meters and provide maximum optical power of 4.5 mW. The stimulator has equal effect to fiber, 30Hz stimulation enhanced the movement of the mice, which demonstrated that the stimulator was qualified for behavior modulation on mice. The closed-loop system could provide 30Hz optical stimulation to the mice and record the EEG fluctuated according to the stimulating frequency with 2KSPS sampling rate, which was important for making closed-loop strategy. In conclusion, according to the requirement of neuromodulation on small freely moving animal in vivo, this paper developed a wireless optical stimulator and a closedloop neuromodulation system. Performance tests and experiments on mice showed that both optical devices were competent to activate ion channel, which established a miniaturized optogenetics system for behavior modulation on freely moving animal. This work will help facilitate the application of optogenetics on the study of neural circuit and mechanisms of nerve disease.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/49270
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	袁明军. 光遗传学无线光刺激器与闭环调控系统研制[D]. 中国科学院大学,2015.

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