Summary

在头固定小鼠胡须信号眨眼经典条件反射

Published: March 30, 2016
doi:

Summary

The preparation presented here for whisker-signaled eyeblink conditioning in head-fixed mice precisely stimulates specific whiskers while allowing mice to ambulate on a cylindrical treadmill. A whisker stimulation conditioned stimulus (CS) paired with a periorbital shock unconditioned stimulus (US) results in reliable associative learning on this apparatus.

Abstract

Eyeblink conditioning is a common paradigm for investigating the neural mechanisms underlying learning and memory. To better utilize the extensive repertoire of scientific techniques available to study learning and memory at the cellular level, it is ideal to have a stable cranial platform. Because mice do not readily tolerate restraint, they are usually trained while moving about freely in a chamber. Conditioned stimulus (CS) and unconditioned stimulus (US) information are delivered and eyeblink responses recorded via a tether connected to the mouse’s head. In the head-fixed apparatus presented here, mice are allowed to run as they desire while their heads are secured to facilitate experimentation. Reliable conditioning of the eyeblink response is obtained with this training apparatus, which allows for the delivery of whisker stimulation as the CS, a periorbital electrical shock as the US, and analysis of electromyographic (EMG) activity from the eyelid to detect blink responses.

Introduction

眨眼调理巴甫洛夫条件反射的一种形式,调查联想学习和记忆的神经机制的模型系统。它已在各种物种,包括人类,兔,猫,大鼠和小鼠中进行了研究。该模式包括两个配对的刺激的呈现:中性条件刺激(CS; 例如 ,一个音,一道闪光,或晶须刺激),以及一个突出的非条件刺激(US; 例如 ,吹气的眼睛,或眶周震)。美国引发的无条件的,反身眨眼反应( ,UR)。最终,经过配对的CS-美国的一些演讲,主题学习到CS与美国相关联。这个学习表现为一个条件反应(CR),仅由在CS在先于美国的演示引起一个眨眼的形式。

在跟踪的形式眨眼调理包括一些H的无刺激间隔undred毫秒分隔CS和美国( 图1)。跟踪空调是声明学习的一种形式,因为它需要刺激偶然性1意识。颞间隙要求动物保持CS的神经'跟踪'前脑区域如海马,以便美国和CS成为相关1-6。随着前脑区域,痕迹条件也依赖于小脑7。

眨眼调理,因此,对于存储器的多个方面,包括采集,合并,和检索的调查一个有用的范例。期间眨眼空调,动物的对照组呈现不成对的刺激以随机顺序来测试pseudoconditioning或致敏反应到CS可以由美国介绍单独而不是学习的CS-US关联而引起的。

常用的appara土族的眨眼调理的啮齿类动物的调查是其中啮齿动物被允许在训练过程中8-10自由行动室。与这种类型的装置中,系绳通常附连到被固定在啮齿动物的头骨头饰。系绳允许与美国(有时在CS)的递送和用于发送动物的对这些刺激( 眨眼反应)10的响应。系绳本身可以基于刺激的类型来修改递送和眨眼响应如何被记录。

之所以使用“自由移动”拴小鼠眨眼条件是,对小鼠克制斗争。虽然其他物种可能是更适合的约束,在眨眼调理实验使用的小鼠的主要优点是,大多数可用的遗传修饰的突变体菌株的是小鼠品系。除了挣扎,完整的资源小鼠traint导致急性窘迫。最大限度地减少应力的头固定鼠标准备将增加可眨眼调理过程中获得的生理信息。例如,该系统将允许用2-光子显微镜11的皮层神经元的成像。

头固定制剂已在以前的实验用于通过可拆卸颅植入的皮质光学成像被使用, 啮齿类动物的脑与四极管阵列,双光子钙成像的体内电生理记录,也可作为在小鼠中11为眨眼调理的平台-16。

在头部固定系统,可靠的刺激和录音,确保没有鼠标( 图2)完全克制。像中的自由移动系统中使用的一项所述的头盔固定到小鼠的颅骨。在训练期间,头状被固定到被连接到棒上的连接器为了一圆柱形的跑步机,以稳定的啮齿动物的头部( 图2A)。圆柱形跑步机允许鼠标舒适休息,但如果鼠标愿意,也允许其运行或行走。与使用该系统,小鼠可以用晶须振动作为CS和温和的眶周触电,因为美国的( 图1)进行培训。美国正在通过导线手术放置在皮肤侧至眼睛下方输送。在CS经由附加到一个2层为矩形的弯曲致动器( 图2B)的梳递送。梳子和弯曲致动器,然后附着到正在训练期间移动到适当的位置,并调整为每个单独的动物的最佳递送的磁性底座。梳子被定位成跨在所选晶须。期间交付的CS,一个信号被发送到弯曲致动器位移的梳子和导致晶须17的振动。

<p class=“jove_content”>其他刺激如音调或光的闪光灯已被用作在小鼠中有效条件刺激过去16,18,19。究其原因晶须刺激选择了CS这个实验范式是鼠类动物的勘探过程中他们的触须对躯体感觉信息输入的依赖。晶须刺激已被证明是可靠的和有效的CS 20。此外,鉴于触须系统( ,桶皮质),晶须刺激的成熟和有组织的皮质衬底作为CS提供映射与学习眨眼空调20,21相关的皮层变化和可塑性优雅的工具。头部固定系统允许对选定的晶须的精确刺激比较刺激神经元和非刺激晶须接收输入神经元之间的反应。最后,小鼠多株表现出与年龄相关的听力损失是相对年轻的成年人<su在空调闪烁期间P> 22,且眼睑闭合改变一个可视化的CS(虽然视觉CS确实改善问题与惊跳反应16)。晶须刺激不受任一这些并发症。

这里介绍的是在对方头部固定筹备眨眼空调,包括CS和美国交付方式独特而重要的修改,并收购了眨眼反应。此装置和在眨眼调理训练模式的可靠性通过学习从空调小鼠和从pseudoconditioned对照动物( 图7A)的相对平坦的学习曲线的曲线证明。

Protocol

所有涉及小鼠程序按照批准的西北大学的机构动物护理和使用委员会基于美国国立卫生研究院颁布了准则的协议进行。 1.缸(图2A) 如由Chettih 等人和Heiney 等人描述构建圆柱体。从长泡沫圆柱体14-15。切割滚筒的10cm的长度,并通过中心钻一个孔,以适应轴,直径金属杆12.7毫米(0.5英寸)。如Heiney 等或其他支持( 如有机玻璃<s…

Representative Results

8-10周龄雄性C57BL6 / J小鼠接受了关于头部固定圆柱形跑步机设备跟踪眨眼空调。 8小鼠配对CS-美国演讲(条件组)和9只小鼠进行了培训未成对CS和美国的演讲(pseudoconditioned组)进行了培训。 从调节的小鼠的条件性响应的示例肌电图记录示于图3和4。肌电图记录每次试验的进行整流,并用10毫秒的时间?…

Discussion

经典眨眼调理联想学习有助于理解基础的学习和记忆的神经基板的有用工具的一种形式。如小鼠在啮齿类眨眼调理采用以前的方法涉及,允许用于动物至约自由移动的腔室。用于在小鼠中眨眼调理的磁头固定制剂,使用在西格尔等人在光诱发痕量眨眼调理由Chettih 人和Heiney 等人 ,最近利用所描述的装置提供了几个优点,如允许某些眨眼调理该没有可能或在过去已被限制( <e…

Disclosures

The authors have nothing to disclose.

Acknowledgements

这项工作是由美国国防部(W81XWH-13-01-0243)和美国国立卫生研究院(R37 AG008796)的资助。我们感谢艾伦·贝克在美国西北大学的机械加工车间建设头固定筒设备。我们感谢Shoai服部博士,他在MATLAB和Solidworks指导。我们感谢约翰功率博士对于控制实验中的LabVIEW软件。

Materials

Exervo TeraNova Foam Roller 36" x 6"  Amazon B002ONUM0E For cylinder
Plexiglas Custom-made; 1 cm thick
Metal Rods (12.7mm diameter) Custom-made
4-40 machine screw (.25 in long) Amazon Supply  B00F33Q8QO For cylinder
Classic Design Hair Comb Conair 93505WG-320 For whisker stimulation
2-Layer Rectangular Bending Actuator Piezo Systems T220-A4-303X  For whisker stimulation
Solder and Flux Kit Piezo Systems MSF-003-NI For whisker stimulation
Magnetic Base Thor Labs MB175 For whisker stimulation
Threaded rod for magnetic base Custom-made
Strips based on 221 series nylon strip connectors from Electronic Connector Corp. Custom-made, based on Weiss and Disterhoft, 2008
TO-220 Style Transistor Amazon Supply B0002ZPZYO  For connector; for the wings
Relia-Tac Sockets Electronic Connector Corp. 220-S02 For connector
Relia-Tac Pins Electronic Connector Corp. 220-P02 For headpiece
0-80 stainless steel machine screw (1 in. long) Amazon Supply B000FN68EE Locking Screw
0-80 stainless steel machine screw hex nut (5/32 in. thick) Amazon Supply B000N2TK7Y Locking Screw Head
Loctite Super Glue-Liquid Loctite 1365896 Cyanoacrylic glue; for the locking screw
Quick Setting Epoxy Ace Hardware 18613 For connector and whisker stimulation system
Ethernet Cable Wires Ethernet cable can be taken apart to use the individual wires for the connector
Polyimide coated stainless steel wires (2 in. long, .005 in. diameter) PlasticsOne 005sw/2.0 37365 S-S  For headpiece, EMG and shock wires
Stainless steel uncoated wire (.005 in. diameter) AM Systems 792800 For headpiece, ground wires
Tenma Variable Autotransformer Tenma 72-110 For the whisker stimulation; rheostat to adjust current to the bending actuator
Amplifier A-M Systems 1700 Amplifier for filtering and amplifying EMG signals
WPI A385R stimulus isolator World Precision Instruments 31405 For the electrical shock
Isothesia (Isoflurane) Henry Schein: Animal Health 50031 For surgery; anesthesia
Buprenex Injectable CIII Reckett Benckiser Pharmaceuticals Inc NDC 12496-0757-1 For surgery; analgesic
Akwa Tears: Lubricant Ophthalmic Ointment  Akorn NDC 17478-062-35 Artificial tear ointment to prevent dry eyes while under anesthesia
Povidine-Iodine Prep Pads PDI NDC 10819-3883-1 For surgery; antiseptic
Alcohol Prep Pads May be purchased from any standard pharmacy
Stainless steel surgical scalpel handles (no.3) Integra Miltex  4-7. For surgery
Stainless steel surgical scalpel blades Integra Miltex 4-310 or 4-315 For surgery; number 10 or 15 scalpel blade
3% Hydrogen Peroxide May be purchased from any standard pharmacy
Micro Clip Roboz RS-5459 For surgery, to hold back skin
00-90 stainless steel machine screw (0.0625 in. long)  Amazon Supply B002SG89X4  For surgery, to wrap ground wire around
Professional Rotary Tool Walnut Hollow 29637 Hand drill for surgery, to drill holes in skull
Inverted Cone Burr Roboz RS-6282C-34 Inverted cone burr size 34; for surgery, to drill holes in skull
Engraving Cutter Drill Bit Dremel 106 Engraving cutter; 1.6 mm bit; for surgery, to drill holes in skull
C&B Metabond-Quick! Cement System "B" Quick Base Parkell S398 For surgery; adhesive luting cement system; important to prevent headpiece avulsion
C&B Metabond-Quick! Cement System Clear L-Powder Parkell S399 For surgery; adhesive luting cement system; important to prevent headpiece avulsion
C&B Metabond-Quick! Cement System "C" Universal TBB Catalyst 0.7 ml Parkell S371 For surgery; adhesive luting cement system; important to prevent headpiece avulsion
C&B Metabond-Quick! Cement System Ceramic Mixing Dish with temperature strip Parkell S387 For surgery; adhesive luting cement system; important to prevent headpiece avulsion
Swiss Tweezers, style #5 World Precision Instruments 504506 For surgery
Puritan Cotton-Tipped Applicators VWR International 10806-005  For surgery
Dental Caulk Grip Cement Kit Dentsply 675570 For surgery; dental cement

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Cite This Article
Lin, C., Disterhoft, J., Weiss, C. Whisker-signaled Eyeblink Classical Conditioning in Head-fixed Mice. J. Vis. Exp. (109), e53310, doi:10.3791/53310 (2016).

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