构建局部场势微电极，用于同时从多个脑结构 进行体内 记录
Summary
本方案描述了定制微电极阵列的构建，以同时记录来自多个大脑结构 的体内 局部场电位。
Abstract
研究人员通常需要同时记录来自几种大脑结构的局部场电位（LFP）。从多个所需的大脑区域进行记录需要不同的微电极设计，但市售的微电极阵列通常不提供这种灵活性。在这里，本协议概述了定制微电极阵列的简单设计，以在不同深度同时记录来自多个大脑结构的LFP。这项工作描述了双侧皮质，纹状体，腹外侧丘脑和黑质微电极的构造作为示例。概述的设计原理提供了灵活性，微电极可以通过计算立体定位坐标并相应地快速更改结构以针对自由移动或麻醉小鼠中的不同大脑区域进行修改和定制，以记录任何结构中的LFP。微电极组件需要标准工具和耗材。这些定制的微电极阵列使研究人员能够轻松设计任何配置的微电极阵列来跟踪神经元活动，从而提供毫秒级分辨率的LFP记录。
Introduction
局部场电位（LFP）是从大脑细胞外空间记录的电势。它们由神经元外部的离子浓度失衡产生，代表一小群局部神经元的活动，与宏观尺度的脑电图记录相比，可以精确地监测特定大脑区域的活动1。据估计，相隔1毫米的LFP微电极对应于两个完全不同的神经元群体。脑电图信号由脑组织、脑脊液、颅骨、肌肉和皮肤过滤，而LFP信号是局部神经元活动的可靠标志物1。
研究人员通常需要同时记录来自几种大脑结构的LFP，但市售的微电极阵列通常不提供这种灵活性。在这里，本方案描述了完全可定制，易于构建的微电极，以同时记录来自不同深度的任何所需大脑区域的LFP。虽然LFPs已被广泛用于记录特定大脑区域2，3，4，5，6，7，8，9的神经元活动，但当前易于定制的设计允许记录来自任何多个浅表或深部大脑区域的LFP11，12.还可以修改该协议，通过确定大脑区域的立体定位坐标并相应地组装阵列来构建任何所需的微电极阵列。这些微电极具有10 kHz采样率和60-70 kΩ电阻（2 cm长度），使我们能够以毫秒级精度记录LFP。然后，数据可以通过16通道放大器放大，滤波（低通1 Hz，高通5 kHz）并数字化。
Protocol
Representative Results
Discussion
从历史上看，微电极阵列已被广泛用于记录来自感兴趣的特定大脑区域2，3，4，5，6，7，8，9，13的神经元活动。但是，我们简单的微电极设计允许同时从多个结构记录<s…
Disclosures
The authors have nothing to disclose.
Acknowledgements
这项工作得到了美国国立卫生研究院（RO1 NS120945，R37NS119012至JK）和UVA脑研究所的支持。
Materials
| Amplifier 16-Channel | A-M Systems | Model 3600 | Amplifier |
| Cranioplasty cement | Coltene | Perm Reeline/Repair Resin Type II Class I Shade – Clear | Cement to hold microelectrodes |
| Cryostat Microtome | Precisionary | CF-6100 | To slice brain |
| Diamel-coatednickel-chromium wire | Johnson Matthey Inc. | 50 µm | Microelectrode wire |
| Dremel | Dremel | 300 Series | To drill holes in mouse skull |
| Epoxy | CEC Corp | C-POXY 5 | Fast setting adhesive |
| Hemostat | Any | To hold the headset | |
| Forceps | Any | To hold microelectrodes | |
| Light microscope | Nikon | SMZ-10 | To see alignment |
| Ohmmeter | Any | To measurre resistance | |
| Pins (Headers and matching Sockets) | Mill-Max | Interconnects, 833 series, 2 mm grid gull wing surface mount headers and sockets | To attach microelectrodes to |
| Polymicro Tubing Kit | Neuralynx | ID 100 ± 04 µm, OD 164 ± 06 µm, coating thickness 12 µm | Glass tubes |
| Pulse Stimulator | A-M Systems | Model 2100 | To mark the microelectrode location at the end of the recordings |
| Scissors | Any | To cut microelectrodes | |
| Superglue | Gorilla | Adhesive | |
| Thick wire 0.008 in. – 0.011 in. | A-M Systems | 791900 | Tick wire to hold the microelectrode array |
| Thin wire 0.005 in. – 0.008 in. | A-M Systems | 791400 | Thin wire for reference and ground |
References
- Buzsáki, G., Anastassiou, C. A., Koch, C. The origin of extracellular fields and currents-EEG, ECoG, LFP and spikes. Nature Reviews Neuroscience. 13, 407-420 (2012).
- Hubel, D. H., Wiesel, T. N. Receptive fields of single neurones in the cat’s striate cortex. The Journal of Physiology. 148 (3), 574-591 (1959).
- O’Keefe, J. Place units in the hippocampus of the freely moving rat. Experimental Neurology. 51 (1), 78-109 (1976).
- Fyhn, M., Molden, S., Witter, M. P., Moser, E. I., Moser, M. B. Spatial representation in the entorhinal cortex. Science. 305 (5688), 1258-1264 (2004).
- Buzsáki, G. Large-scale recording of neuronal ensembles. Nature Neuroscience. 7, 446-451 (2004).
- Buckmaster, P. S., Edward Dudek, F. In vivo intracellular analysis of granule cell axon reorganization in epileptic rats. Journal of Neurophysiology. 81 (2), 712-721 (1999).
- Driscoll, N., et al. Multimodal in vivo recording using transparent graphene microelectrodes illuminates spatiotemporal seizure dynamics at the microscale. Communications Biology. 4, 1-14 (2021).
- Roy, D. S., et al. Memory retrieval by activating engram cells in mouse models of early Alzheimer’s disease. Nature. 531, 508-512 (2016).
- Igarashi, K. M., Lu, L., Colgin, L. L., Moser, M. B., Moser, E. I. Coordination of entorhinal-hippocampal ensemble activity during associative learning. Nature. 510, 143-147 (2014).
- Gage, G. J., Kipke, D. R., Shain, W. Whole animal perfusion fixation for rodents. Journal of Visualized Experiments. (65), e3564 (2012).
- Brodovskaya, A., Shiono, S., Kapur, J. Activation of the basal ganglia and indirect pathway neurons during frontal lobe seizures. Brain. 144 (7), 2074-2091 (2021).
- Ren, X., Brodovskaya, A., Hudson, J. L., Kapur, J. Connectivity and neuronal synchrony during seizures. The Journal of Neuroscience. 41 (36), 7623-7635 (2021).
- Chang, E. H., Frattini, S. A., Robbiati, S., Huerta, P. T. Construction of microdrive arrays for chronic neural recordings in awake behaving mice. Journal of Visualized Experiments. (77), e50470 (2013).
