Summary

急性<em>体内</em>麻醉大鼠超导途径局部场电位和多单位活动的电生理记录

Published: June 22, 2017
doi:

Summary

在本研究中,介绍了如何在尿烷麻醉下从超直接途径进行多位点体内电生理记录的方法。

Abstract

融合证据表明,许多神经精神疾病应被理解为大规模神经元网络的紊乱。为了更好地了解这些疾病的病理生理基础,有必要精确地表征电路的不同神经元部分之间的信息处理在哪种方式的干扰。使用细胞外体内电生理记录,可以精确地描绘神经元网络内的神经元活动。该方法的应用与替代技术相比具有几个优点, 例如功能磁共振成像和钙成像,因为它允许独特的时间和空间分辨率,并且不依赖于遗传工程生物体。然而,细胞外体内记录的使用是有限的,因为它是不能普遍应用的侵入性技术。在本文中,介绍一种简单易用的方法可以在网络的多个位置同时记录细胞外电位,例如局部场电位和多单元活动。详细说明如何使用立体定向手术和多单位记录的在线分析来实现皮质下核的精确定位。因此,证明了在麻醉动物体内如何研究完整的网络如超直肠皮质基底神经节环。

Introduction

最近关于不同神经精神障碍如帕金森病(PD)和精神分裂症的累积证据强烈地表明,他们的病理生理学是基于经常涉及皮层和皮质下结构1,2,3的延长的神经元回路的关键功能障碍。根据这一理论,疾病的临床表现是由于细胞网络的信息处理能力受损,而不是单个细胞或特定神经元素1,2,3的结果 。为了增强对这种复杂的神经精神疾病组的了解,并找到新的治疗方案,必须非常详细地描述人类患者和动物模型中无序网络的神经元动力学。优秀研究生物科目大规模网络的方法是细胞外电位的多位点电生理记录4 。使用这种方法,可以同时评估局部场电位(LFP),其主要表示由突触前电位5产生的兴奋性和抑制性突触后电流和多单位活性(MUA)的时间总和。细胞外电位的记录与研究网络的其他方法( 例如功能性磁共振成像和钙成像)相比具有几个优点,因为它提供了更高的时间和空间分辨率,并且因为它不依赖于遗传工程生物体5 。然而,细胞外体内记录的使用是有限的,因为它是不能普遍应用的侵入性技术。

体内电生理记录可以在清醒和麻醉的动物中执行排序6 。这两种方法都伴随着具体的利弊。清醒动物的研究允许在执行定义的行为任务期间记录大脑信号,但容易发生运动相关和其他工件7,8 。另一方面,麻醉动物的记录提供了在高度定义的皮层同步状态下用最少的人造物评估LFP和MUA的机会,但是结果在一定程度上也与清醒对象9,10,11中可以发现的有所不同。

近年来,已经证明,LFP的抽样对于描绘网络活动的病理变化特别有用。其中一个突出的例子是人类患者PD的病理生理学研究和动物模型,其中可以显示皮质基底节神经节循环中增强的β振荡与帕金森症运动症状12,13相关 。作为这一研究的结果,目前正在研究β振荡是否可以用作闭环深层脑刺激的在线反馈生物标志物14,15

在本研究中,提供了用氨基甲酸酯麻醉的大鼠中LFP和MUA的急性多位点体内电生理记录的详细描述。证明如何通过电生理学使用标准和定制的电极以及如何构建这些电极来完整的网络,例如超直接皮层 – 基底神经节途径。特别强调如何通过co实现基底节神经核的精确靶向将立体定向手术与MUAs的在线注册相结合。

Protocol

实验程序按照德国“动物福利法”(2014年最后修订)和欧洲条例(2010/63 / EU)进行。实验由当地动物福利机构(LaGeSo,Berlin)批准,符合当地部门和国际准则。 注意:在所提出的方法中,使用两个模型的电极从连接主运动皮质(M1)与底丘核(STN)和黑质基质(SNr)连接的超直接皮质基底神经节途径记录。对于使用M1定制低阻抗Ag / AgCl电极的硬膜外皮质电图(ECoG)记录。来?…

Representative Results

使用本文使用的记录电极,可以从STN和SNr从初级运动皮层,下丘脑核和黑质分布样本LFPs和网状细胞。最初,LFP和多单元活动一起记录在宽带信号中。此后,LFP和MUA被带通滤波器分离(LFP为0.05-250Hz,MUA为300-4,000Hz)。 为了正确定位皮质下核,特别是小结构如STN,有利的是将计划的立体坐标与在线记录的MUA信号对齐。对于可以记?…

Discussion

在本研究中,该方法证明了如何使用连接M1与啮齿动物的STN和SNr的超直接皮层 – 基底神经节途径的实例同时从给定网络的多个位点记录细胞外电生理信号。

记录小皮质结构如STN的关键步骤是将记录电极精确地引导到靶中。在所提出的方法中,注意两个关键步骤确保了目标的高准确性。在将电极引入大脑之前,在立体定向装置中制备动物时,绝对必须确保将头骨带入“平头颅骨…

Declarações

The authors have nothing to disclose.

Acknowledgements

我们感谢德意志民主共和国(DFG),KFO 247,为我们的研究提供资金。

Materials

Ag/AgCl custom epidural electrodes Goodfellow GmbH
D-61213 Bad Nauheim, Germany
info@goodfellow.com
Product-ID AG005127 for 99.99% silver wire Ag/AgCl electrodes will allow for better signal quality, but may only be used in acute experiments. Possible replacement: Stainless steel electrodes
Stereotaxic holder with acrylic block David Kopf Instruments,
7324 Elmo Street, Tujunga, CA 91042, USA
Product ID Model 1770 Standard Electrode Holder Make sure the acrylic block has recesses which suit the electrode setup for the desired target. Acrylic blocks can easily be modified with a file to obtain the desired configuration. Possible replacement: Self-constructed electrode holders
Tungsten microwire electrodes 1.5 MΩ impedance Microprobes.com
18247-D Flower Hill Way  Gaithersburg, Maryland, 20879 USA
Product-ID WE3ST31.5A5-250um The 1.5 MΩ is necessary to record MUA and LFP at the same time. Possible replacement: Microelectrodes of different materials can be used. The electrodes have to be straight, robust and as thin as possible.
Rat alignment tool David Kopf Instruments,
7324 Elmo Street, Tujunga, CA 91042, USA
Product ID Model 944 Rat Alignment Tool Allows the exact orientation of the brain to match stereotaxic atlases. Possible replacement: Stereotaxic holder with a cannula
Two-component dental acrylic Associated Dental Products Ltd.
Kemdent Works, Purton, Swindon
Wiltshire, SN5 4HT, United Kingdom
Simplex Rapid Powder Clear 225g, Product code: ACR803; Simplex Rapid Liquid 150ml, Product code: ACR920 Depending in the electrodes used, superglue might be an easy alternative, if the electrodes are small and lightweight. Possible replacement: Superglue (Cyanacrylate-based)
Faraday cage Self-construction A proper Faraday cage will be the best protection from electromagnetic artifacts, but everything which can be formed into a box shape or applied to a frame and is made of conductive material may help. Possible replacement: Aluminum foil or copper mesh
Electrophysiological setup with recording software and online spike-sorting capabilities OmniPlex® Neural Data Acquisition System
Plexon Inc
6500 Greenville Avenue, Suite 700
Dallas, Texas 75206
USA
Offline sorting software is a potential alternative, multiple scripts and softwares can be found for free in the open source community.

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Haumesser, J. K., Kühn, J., Güttler, C., Nguyen, D., Beck, M. H., Kühn, A. A., van Riesen, C. Acute In Vivo Electrophysiological Recordings of Local Field Potentials and Multi-unit Activity from the Hyperdirect Pathway in Anesthetized Rats. J. Vis. Exp. (124), e55940, doi:10.3791/55940 (2017).

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