The authors would like to thank the George Washington University Facilitating Fund for financial support of the project. Mr. Patel is grateful the George Washington University School of Engineering and Applied Science Summer Undergraduate Program in Engineering Research and the Undergraduate Research award for financial support. Finally, we are grateful to the GWU Center for Biomemetics and Bioinspired Engineering (COBRE) for use of facilities controlled by the center.

1.数字化海狮Foreflipper的标本<ol><li>扫描海狮foreflipper的标本。 <ol><li>获取海狮的鳍状肢的从死者的个人（ 图1a）的标本。 注:在我们的例子中，他们从史密森动物园在华盛顿特区，获得</li><li>从基（其中foreflipper重视动物的身体）垂直悬挂的foreflipper。这既可以在扫描时导板是直的，并公开在整个表面进行扫描。 </li><li>扫描导板用高分辨率结构光扫描仪，具有约0.5mm的精确度，以及大约0.1mm的错误（ 图1b）。 </li></ol></li><li>导入点云到CAD软件，并使其作为表面。要做到这一点，点击"打开"，然后选择所需obj文件。点击"导入"将文件导入到CAD软件。 </li><li>使用操作生成点云计算机辅助设计（CAD）单击"剪切挤压"和裁剪扫描的肉部分（不需要的部分）的软件。接下来，点击"规模"获得了机器人的鳍状肢（全尺寸的68％），适当的缩放。通过比较试样原始（ 图2）检查是否有足够的细节捕获脚蹼。 </li><li>创建围绕挡板的模具。 <ol><li>在CAD软件中，使用导板表面，以形成通过创建围绕导板表面上的周围体积的模具。通过点击"草图"绘制一个矩形挤出矩形块，然后将其挤出超过挡板的高度，以完全包围它做到这一点。 </li><li>点击"大会"和进口两部分（鳍和矩形块）进入工作区。点击"伴侣"和使导板和模具既作为重合的前部和顶部平面。这会自动将模具内的鳍状肢。 </li><li>塞莱CT从设计树模，然后单击"编辑零件"。一旦零件被选定后，点击"插入&gt;特征&gt;腔&#39;，使模具内的鳍状肢的空腔。在矩形模具中心绘制一条线，然后点击"分割"成相同的模具两部分组成。 </li><li>单击"剪切部分"周围的量分成两部分，方便鳍提取。将卷的各占一半龋齿和钉并将其保存为第一部分和两个鳍模具（ 图3）。 </li><li>转换模具".STL&#39;的&#39;.SLDRPT"文件。这些文件导入到3D打印机的专用软件，然后点击"打印"来生成3D打印的模具。 </li></ol></li></ol> 2.设计的骨骼结构<ol><li>打开数字foreflipper在CAD软件并获得海狮foreflipper骨骼结构作为参考的图像（如 数字1在英国，1977年19）。 </li><li>设计了三种不同的部分，模仿骨结构将适合的foreflipper的数字模型内。贯穿此过程，"碱"是指一个部分的末端更靠近foreflipper和"尖端"的基础是指部分更靠近foreflipper的尖端的端部。 <ol><li>底座块<ol><li>让这片的长度成正比，肩关节和海狮的鳍状肢的腕间的距离（测量使用卷尺获得）。为此通过点击&#39;素描&#39;和设计的基片的形状（ 图4）使用CAD软件。 </li><li>通过点击"素描"和绘画两个圆形添加在部分的两端关节。点击&#39;凸台拉伸&#39;从基片的平面挤出所需的长度。通过单击"剪切挤压"，使点击小圆圈切入拉伸的草图空间轴。为了加强这个联合，点击"圆角"来平滑锐利关节。 注意:圆的尺寸取决于轴的大小在安装导板的水槽的顶部期间使用。在我们的情况下，较小的圆的直径为0.5英寸，更大的圆为1英寸。基端会坐在挡板皮肤几何外面，所以指关节的大小不皮肤的约束下落。 </li></ol></li><li>中段<ol><li>让这片的长度成正比，腕关节和海狮的万向接头之间的距离。通过点击"草图"和在一个平面上绘制所希望的形状（ 如图4b中所示）执行此操作。一旦几何设计，点击"挤出"，以获得中间片的基本的三维形状。输入挤压长度0.1650英寸。 注意:中间片的所希望的形状在我们的实验是为2.25英寸的高度和两个基地分别1.625和0.850英寸长度的梯形。 </li><li>加入两端关节。如步骤2.2.1.2所述做到这一点。挤出的切割的直径为0.125英寸。连接的基端向基片与阿克塞尔的前端的关节，以形成表示该腕关节的铰链。 注:关节需要适应foreflipper的体积内，所以相应的设计。 </li><li>添加一个塔的高度大约1cm到片两侧的前端。 <ol><li>要添加一个塔，点击"素描"和模型的基础上绘制一个矩形。通过选择草图并单击"凸台拉伸"拉伸草图。在这个特殊的情况下，塔的厚度为0.165英寸。 </li><li>点击"圆角"，并选择该模型和挤出的塔的一个边缘。这加强了尖锐的接合处的塔和巴中间一块本身相连。它是好的，如果塔从皮肤的几何形状突出。塔应该足够厚，以承受导板拍手期间产生的力。参见图4，以供参考。 </li></ol></li></ol></li><li>提示件<ol><li>让这片的长度成正比关节关节和海狮的最长的手指骨的尖端之间的距离。通过点击"素描"，并在一个平面上草绘所需形状做到这一点。一旦几何设计，点击拉伸得到的尖端件的基本的三维形状。 </li><li>加入两端关节。如步骤2.2.1.2所述做到这一点。挤出的切口的直径应等于车轴，在该实验中为0.125英寸的直径。在基端指关节将被连接到中间片有一轴的前端，以形成表示该叉形接头的铰链。这些KNU的几何形状ckles需要以适合foreflipper皮肤的几何形状内，因此设计相应。 </li><li>添加一个塔的高度大约1cm到片两侧的基端部。执行此步骤2.2.2.3所述。在这个特殊的情况下，塔的厚度为0.165英寸。它是好的，如果塔从皮肤的几何形状突出。塔应该足够厚，以承受导板拍手期间产生的力。参见图5，以供参考。 </li></ol></li></ol></li></ol> 3.创建一个翻转<ol><li> 3D打印的鳍状肢的骨架（基地，中部和尖端件）。从CAD转换".SLDRPT&#39;文件&#39;.STL"，并将其导入到打印机的专用软件，然后点击"打印"。 注:打印指令是为每个打印机不同。 <ol><li>加强中间和末梢段的关节用粘合剂（环氧树脂）和碳线程。要做到这一点，削减碳水化合物对长0.750英寸线程。胶粘剂应用到3D打印骨骼结构打下了指关节的线程。这是没有必要加强在基片（ 图5a）的大关节。 </li><li>在每个底部钻孔塔芳纶字符串（字符串，将用于致动关节）的直径。 </li><li>从基本组装所有骨片共同使用车轴给小费。通过放置在平坦的表中的所有组件， 如图4所示做到这一点。连接的基极和中间片，对准零件的转向节并插入轴。使用相同的技术到中间和顶端件连接在一起。每个轮轴的每个端部使用粘合剂以确保车轴不移动横向（ 图5b）。 </li><li>切割塑料管，以下列长度。切四个管子的基骨片（L 1 = 8厘米），两个管的中间片（L 2 = 6厘米）的长度的长度。 </li><li>切4片千电子伏拉尔串，每次3英尺长。 </li><li>通过L 1管那么L 2管幻灯片一根弦。通过L 1管滑到另一个字符串。重复此过程，其余管和串。 </li><li>放置在骨骼结构的顶部的管，并使用一透明胶带，以暂时保持它们在适当的位置。使用粘合剂，坚持管到骨骼结构，然后取出磁带。 注意:没有在其中管具有被置于特定位置，关键方面是只要坚持他们的结构的表面上。使用图5c作为指导。 </li><li>如在步骤3.1.2所述螺纹由L 1管和L 2管钻通到尖端和中间片孔中的芳纶串。做一个小而安全的结，一旦字符串是通过孔（ 图5d）。 </li></ol></li><li>加入导板的皮肤以创建最终脚蹼。 <ol><li>测量200毫升的SILIC上，并在两个不同的容器中的硅介质。 </li><li>既倒这些液体入钢碗。添加漆稀释剂（不超过总重量的混合物的10％），以该混合物为容易倾倒和混合。 </li><li>使用一台搅拌机混合彻底为3混合 - 4分钟。颜色可以在这一步骤以获得所需的视觉效果添加。如果一台搅拌机不可用，用打蛋器混合，小心刮容器的侧面和底部。 </li><li>插入杆插入基部的关节和与导板模具的指关节对齐。当栓装配到模具的空腔中，骨骼结构在导板模具完全对齐。同时按住上模具的两部分，通过使用夹具为增加压缩（该步骤是关键的，以使硅混合物不会从两部分之间的间隙泄漏）固定的部分。 </li><li>一旦该混合物混合，小心地倒在模具直到最上面的指关节的骨结构。的从模具中的底部孔液体渗出是混合物的标志得到均匀分布的。在此开始时，孔堵塞，以避免液体的进一步流动。离开液体从模具中取出挡板机器人之前固化四小时（参见图6）。 </li></ol></li></ol> 4.安装<ol><li>为安装在水槽（ 图7）的硅foreflipper，创建的安装结构。成品组装的CAD形式呈现。 （ 图8）。 <ol><li>设计一个板用CAD软件精心拉伸切除。点击"素描"，并绘制尺寸的矩形14×19英寸（如激光切割机采用了.dwg文件的高度并不重要）。使用钢材的矩形板为基数，以制造这种板。载连接到一个钢激光切割器以获得所需的削减的计算机上从CAD软件的二维绘图。 注:氏盘子里的房子电机和它允许滑轮系统工作晋级。板的宽度是相等的水槽的宽度，从而使得更容易地将板在水槽滑动。这种类型的安置在方便拆卸安装组件的帮助，以取代部分或foreflipper模式。 </li><li>修复foreflipper和滑轮到轴上，这滑入三角桁架。 注:三个滑轮系统被实施为从电机到杆传送的扭矩/功率。 </li><li>使用两侧轴承帮助杆转动平稳。限制杆的在左右方向的移动，放置轴环在轴的各端。 </li></ol></li><li>通过在驱动程序中选择点动功能设置的鳍状肢的运动。按"上"键鳍顺时针旋转和"向下"按钮旋转脚蹼逆时针。该驱动程序允许改变电动机每分钟转数根据在手册20的说明轴上。 </li><li>插入在水中的直角染料端口和增加该染料体系上的压力。调整染料的速度到水的自由流速度，以便该染料显示为一个单一的平滑长丝。旋转挡板使染料相互作用并获取被困产生所得涡流。 </li></ol>

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The authors have nothing to disclose.

机器人脚蹼设备将使我们能够理解游泳加州海狮的流体力学。这包括基本推力产生行程（即&#39;霹&#39;），以及动物研究不能调查非物理变化。机器人起落已被设计为实验的多功能性，从而，步骤3，其中本身挡板制成-是在获得所期望的结果是至关重要的。尽管这种装置是，很显然，仅有活系统的模型， 在加州海狮的原位研究是极其困难的和可能的数据的范围是相当有限的。 <p clas...

虽然科学家已经研究了海狮游泳（热力学，运输成本，风阻系数，线性速度和加速度1-3的基本特征，我们缺乏对系统的流体动力学的信息。如果没有这个知识，我们限制潜在的高速，高机动性工程应用到身体的尾鳍（BCF）运动款4。通过表征不同的游泳范式，我们希望扩大我们的设计工具目录，特别是那些有潜力实现更安静，游泳的隐秘的形式。因此，我们使用机器人海狮foreflipper 5,6通过加州海狮和实验室调查的直接观察研究海狮游泳的基本机制。 要做到这一点，我们会聘请探索复杂的生物系统中常用的技术:机器人平台7。一些运动的研究，机器人步行8,9和游泳10 -具备h的是基于对动物的任何复杂的11或高度简化的12机械模型。通常情况下，机器人平台保留了模型系统的精髓，同时让研究人员能够探索大型参数空间13-15。虽然不总是表征整个系统，多是通过这些平台，隔离机车系统的单个组分了解到。例如，不稳定推进器的基本功能的，比如背部和往复扫carangiform游泳时的尾鳍，已通过激烈投球和/或起伏板12,16,17,18的实验研究探讨。在这种情况下，我们可以隔离的方式，基于动物研究不能这种复杂的运动的某些模式。推进的那些基本方面然后可以在不需要生物复杂性进化提供车辆的设计中使用。 （Zalophus californianus）标本的生物扫描准确的。该roboflipper被致动以复制从以前的研究1衍生的动物的运动。这个机器人脚蹼将用于调查游泳海狮的水动力性能，并探索比动物研究中，尤其是那些大的水生哺乳动物更宽参数空间，可以产生。

<table><tbody><tr><td>Dragon Skin 20</td><td>Smooth-on</td><td></td><td></td></tr><tr><td>Dragon Skin 20 medium</td><td>Smooth-on</td><td></td><td></td></tr><tr><td>Object24</td><td>Stratasys</td><td></td><td>3D printer</td></tr><tr><td>Stand Mixer</td><td>Hamilton</td><td></td><td></td></tr><tr><td>PKS-PRO-E-10 System</td><td>Anaheim Automation</td><td>PKS-PRO-E-10-A-LP22</td><td>Controller and Servo Motor</td></tr><tr><td>Artec Eva</td><td>Artec 3D</td><td></td><td>3D light scanner with resolution of 0.1 mm</td></tr><tr><td>Artec Spider</td><td>Artec 3D</td><td></td><td>3D light scanner with resolution of 0.5 mm</td></tr><tr><td>Steel plate</td><td>Mcmaster</td><td></td><td></td></tr><tr><td>Carbon Tow</td><td>Fibreglast</td><td>2393-A</td><td></td></tr><tr><td>Hardened Precision 440C Stainless Steel Shaft</td><td>Mcmaster</td><td>6253K49</td><td></td></tr><tr><td>Tygon PVC Clear Tubing</td><td>Mcmaster</td><td>6546T23</td><td></td></tr><tr><td>Kevlar Thread</td><td>Mcmaster</td><td></td><td></td></tr></tbody></table>

a robotic platform to study the foreflipper of the california sea lion

加州海狮（Zalophus californianus），是一种敏捷和强大的游泳运动员。与许多成功的游泳（海豚，金枪鱼），它们产生与大foreflippers大部分推力。本协议描述旨在研究游泳加州海狮（Zalophus californianus）的水动力性能的机器人平台。机器人是动物的foreflipper的模型是由电机致动以复制其推进冲程（即&#39;霹&#39;）的运动。海狮的推进行程的运动是由史密森动物园（SNZ）无人盯防，非研究海狮的视频数据中提取。这些数据构成这里提出的机器人导板的致动运动的基础。机器人的鳍状肢的几何形状是根据一个成年雌性海狮的foreflipper，扩展到全尺寸的鳍状肢的60％左右的高清晰度激光扫描。铰接式模型有3Ĵoints，模仿海狮foreflipper的肘，腕关节和关节。该机器人平台，从静止加速时动力匹配性能雷诺数和小费动物速度的。机器人脚蹼可用来确定性能（力和力矩）和所得的流场。

上述过程产生了加州海狮foreflipper的机器人模型。该模型可以用两种不同的方式使用。一个是由仅在根目录（ 图 6a）致动导板。在这种情况下，驱动马达设置第一关节的旋转速度，但所得到的挡板的运动由弹性导板和周围的水之间的流体 - 结构交互来确定。此外，我们可以创建在两个下接头除了根（ 图 6b）致动机器人脚?...

Watch this Scientific Journal Video about A Robotic Platform to Study the Foreflipper of the California Sea Lion at JoVE.com

A Robotic Platform to Study the Foreflipper of the California Sea Lion

一个机器人平台描述将被用于研究水动力性能，力量和游泳加州海狮-的流场。机器人是动物的foreflipper的模型是由电机致动以复制其推进冲程（即&#39;霹&#39;）的运动。

机器人平台研究加州海狮的Foreflipper

The California sea lion (Zalophus californianus), is an agile and powerful swimmer. Unlike many successful swimmers (dolphins, tuna), they generate most ...

a-robotic-platform-to-study-the-foreflipper-of-the-california-sea-lion

Research

JoVE Journal

Engineering

7.9K 次观看.  The George Washington University. 一个机器人平台描述将被用于研究水动力性能，力量和游泳加州海狮-的流场。机器人是动物的foreflipper的模型是由电机致动以复制其推进冲程（即'霹'）的运动。 

视频: A Robotic Platform to Study the Foreflipper of the California Sea Lion

A Novel Method for Assessing Proximal and Distal Forelimb Function in the Rat: the Irvine, Beatties and Bresnahan (IBB) Forelimb Scale

Several experimental models of cervical spinal cord injury (SCI) have been developed recently to assess the consequences of damage to this level of the spinal cord (Pearse et al., 2005, Gensel et al., 2006, Anderson et al., 2009), as the majority of human SCI occur here (Young, 2010; www.sci-info-pages.com). Behavioral deficits include loss of forelimb function due to damage to the white matter affecting both descending motor and ascending sensory systems, and to the gray matter containing the segmental circuitry for processing sensory input and motor output for the forelimb. Additionally, a key priority for human patients with cervical SCI is restoration of hand/arm function (Anderson, 2004). Thus, outcome measures that assess both proximal and distal forelimb function are needed. Although there are several behavioral assays that are sensitive to different aspects of forelimb recovery in experimental models of cervical SCI (Girgis et al., 2007, Gensel et al., 2006, Ballerman et al., 2001, Metz and Whishaw, 2000, Bertelli and Mira, 1993, Montoya et al., 1991, Whishaw and Pellis, 1990), few techniques provide detailed information on the recovery of fine motor control and digit movement.
The current measurement technique, the Irvine, Beatties and Bresnahan forelimb scale (IBB), can detect recovery of both proximal and distal forelimb function including digit movements during a naturally occurring behavior that does not require extensive training or deprivation to enhance motivation. The IBB was generated by observing recovery after a unilateral C6 SCI, and involves video recording of animals eating two differently shaped cereals (spherical and doughnut) of a consistent size. These videos were then used to assess features of forelimb use, such as joint position, object support, digit movement and grasping technique.
The IBB, like other forelimb behavioral tasks, shows a consistent pattern of recovery that is sensitive to injury severity. Furthermore, the IBB scale could be used to assess recovery following other types of injury that impact normal forelimb function.

A Novel Method for Assessing Proximal and Distal Forelimb Function in the Rat: the Irvine, Beatties and Bresnahan IBB Forelimb Scale

Here we will describe a rodent behavioral assay that can detect recovery of both proximal and distal forelimb function including digit movements during a naturally occurring behavior that does not require extensive training or deprivation to enhance motivation.

一个评估在大鼠近端和远端的前肢功能的新方法：欧文，Beatties和布雷斯纳汉（IBB）前肢规模

Several experimental models of cervical spinal cord injury (SCI) have been developed recently to assess the consequences of damage to this level of the ...

科研

神经科学

Flat-floored Air-lifted Platform: A New Method for Combining Behavior with Microscopy or Electrophysiology on Awake Freely Moving Rodents

It is widely acknowledged that the use of general anesthetics can undermine the relevance of electrophysiological or microscopical data obtained from a living animal&#8217;s brain. Moreover, the lengthy recovery from anesthesia limits the frequency of repeated recording/imaging episodes in longitudinal studies. Hence, new methods that would allow stable recordings from non-anesthetized behaving mice are expected to advance the fields of cellular and cognitive neurosciences. Existing solutions range from mere physical restraint to more sophisticated approaches, such as linear and spherical treadmills used in combination with computer-generated virtual reality. Here, a novel method is described where a head-fixed mouse can move around an air-lifted mobile homecage and explore its environment under stress-free conditions. This method allows researchers to perform behavioral tests (e.g., learning, habituation or novel object recognition) simultaneously with two-photon microscopic imaging and/or patch-clamp recordings, all combined in a single experiment. This video-article describes the use of the awake animal head fixation device (mobile homecage), demonstrates the procedures of animal habituation, and exemplifies a number of possible applications of the method.

This method creates a tangible, familiar environment for the mouse to navigate and explore during microscopic imaging or single-cell electrophysiological recordings, which require firm fixation of the animal&#8217;s head.

平地板的空气解禁平台:一种新方法与显微镜或电对清醒结合行为自由移动鼠害

It is widely acknowledged that the use of general anesthetics can undermine the relevance of electrophysiological or microscopical data obtained from a ...

行为学

Automated Interactive Video Playback for Studies of Animal Communication

Video playback is a widely-used technique for the controlled manipulation and presentation of visual signals in animal communication. In particular, parameter-based computer animation offers the opportunity to independently manipulate any number of behavioral, morphological, or spectral characteristics in the context of realistic, moving images of animals on screen. A major limitation of conventional playback, however, is that the visual stimulus lacks the ability to interact with the live animal. Borrowing from video-game technology, we have created an automated, interactive system for video playback that controls animations in response to real-time signals from a video tracking system. We demonstrated this method by conducting mate-choice trials on female swordtail fish, Xiphophorus birchmanni. Females were given a simultaneous choice between a courting male conspecific and a courting male heterospecific (X. malinche) on opposite sides of an aquarium. The virtual male stimulus was programmed to track the horizontal position of the female, as courting males do in the wild. Mate-choice trials on wild-caught X. birchmanni females were used to validate the prototype's ability to effectively generate a realistic visual stimulus.

Video playback is a widely used technique in animal behavior. We created and evaluated a program that applies rules-based, interactive playback of 3-D computer animations in response to real-time, automated data on subject behavior.

自动化研究动物交流的交互式视频播放

Video playback is a widely-used technique for the controlled manipulation and presentation of visual signals in animal communication. In particular, ...

Investigating Motor Skill Learning Processes with a Robotic Manipulandum

Skilled reaching tasks are commonly used in studies of motor skill learning and motor function under healthy and pathological conditions, but can be time-intensive and ambiguous to quantify beyond simple success rates. Here, we describe the training procedure for reach-and-pull tasks with ETH Pattus, a robotic platform for automated forelimb reaching training that records pulling and hand rotation movements in rats. Kinematic quantification of the performed pulling attempts reveals the presence of distinct temporal profiles of movement parameters such as pulling velocity, spatial variability of the pulling trajectory, deviation from midline, as well as pulling success. We show how minor adjustments in the training paradigm result in alterations in these parameters, revealing their relation to task difficulty, general motor function or skilled task execution. Combined with electrophysiological, pharmacological and optogenetic techniques, this paradigm can be used to explore the mechanisms underlying motor learning and memory formation, as well as loss and recovery of function (e.g. after stroke).

A paradigm is presented for training and analysis of an automated skilled reaching task in rats. Analysis of pulling attempts reveals distinct subprocesses of motor learning.

调查运动技能的学习过程与机器人Manipulandum

Skilled reaching tasks are commonly used in studies of motor skill learning and motor function under healthy and pathological conditions, but can be ...

The Knob Supination Task: A Semi-automated Method for Assessing Forelimb Function in Rats

Tasks that accurately measure dexterity in animal models are critical to understand hand function. Current rat behavioral tasks that measure dexterity largely use video analysis of reaching or food manipulation. While these tasks are easy to implement and are robust across disease models, they are subjective and laborious for the experimenter. Automating traditional tasks or creating new automated tasks can make the tasks more efficient, objective, and quantitative. Since rats are less dexterous than primates, central nervous system (CNS) injury produces more subtle deficits in dexterity, however, supination is highly affected in rodents and crucial to hand function in primates. Therefore, we designed a semi-automated task that measures forelimb supination in rats. Rats are trained to reach and grasp a knob-shaped manipulandum and turn the manipulandum in supination to receive a reward. Rats can acquire the skill within 20 &plusmn; 5 days. While the early part of training is highly supervised, much of the training is done without direct supervision. The task reliably and reproducibly captures subtle deficits after injury and shows functional recovery that accurately reflects clinical recovery curves. Analysis of data is performed by specialized software through a graphical user interface that is designed to be intuitive. We also give solutions to common problems encountered during training, and show that minor corrections to behavior early in training produce reliable acquisition of supination. Thus, the knob supination task provides efficient and quantitative evaluation of a critical movement for dexterity in rats.

This manuscript describes a semi-automated task that quantifies supination in rats. Rats reach, grasp, and supinate a spherical manipulandum. The rat is rewarded with a pellet if the turn angle exceeds a criterion set by the user. This task increases throughput, sensitivity to injury, and objectivity compared to traditional tasks.

旋钮旋任务: 一种半自动评估大鼠前肢功能的方法

Tasks that accurately measure dexterity in animal models are critical to understand hand function. Current rat behavioral tasks that measure dexterity ...

An In Vitro Preparation for Eliciting and Recording Feeding Motor Programs with Physiological Movements in Aplysia californica

Multifunctionality, the ability of one peripheral structure to generate multiple, distinct behaviors1, allows animals to rapidly adapt their behaviors to changing environments. The marine mollusk Aplysia californica provides a tractable system for the study of multifunctionality. During feeding, Aplysia generates several distinct types of behaviors using the same feeding apparatus, the buccal mass. The ganglia that control these behaviors contain a number of large, identified neurons that are accessible to electrophysiological study. The activity of these neurons has been described in motor programs that can be divided into two types, ingestive and egestive programs, based on the timing of neural activity that closes the food grasper relative to the neural activity that protracts or retracts the grasper2. However, in isolated ganglia, the muscle movements that would produce these behaviors are absent, making it harder to be certain whether the motor programs observed are correlates of real behaviors. In vivo, nerve and muscle recordings have been obtained corresponding to feeding programs2,3,4, but it is very difficult to directly record from individual neurons5. Additionally, in vivo, ingestive programs can be further divided into bites and swallows1,2, a distinction that is difficult to make in most previously described in vitro preparations.
The suspended buccal mass preparation (Figure 1) bridges the gap between isolated ganglia and intact animals. In this preparation, ingestive behaviors - including both biting and swallowing - and egestive behaviors (rejection) can be elicited, at the same time as individual neurons can be recorded from and stimulated using extracellular electrodes6. The feeding movements associated with these different behaviors can be recorded, quantified, and related directly to the motor programs. The motor programs in the suspended buccal mass preparation appear to be more similar to those observed in vivo than are motor programs elicited in isolated ganglia. Thus, the motor programs in this preparation can be more directly related to in vivo behavior; at the same time, individual neurons are more accessible to recording and stimulation than in intact animals. Additionally, as an intermediate step between isolated ganglia and intact animals, findings from the suspended buccal mass can aid in interpretation of data obtained in both more reduced and more intact settings. The suspended buccal mass preparation is a useful tool for characterizing the neural control of multifunctionality in Aplysia.

An In Vitro Preparation for Eliciting and Recording Feeding Motor Programs with Physiological Movements in Aplysia californica

We describe a technique to extracellularly record and stimulate from nerves, muscles, and individual identified neurons in vitro while eliciting and observing different types of feeding behaviors in the feeding apparatus of Aplysia.

一个<em在体外</em制备与生理变动，为激发和记录进给电机程序<em&gt;海兔夜蛾</em

Multifunctionality, the ability of one peripheral  structure to generate multiple, distinct behaviors1, allows animals  to rapidly adapt their behaviors ...

Recordings of Neural Circuit Activation in Freely Behaving Animals

The relationship between patterns of neural activity and corresponding behavioral expression is difficult to establish in unrestrained animals. Traditional non-invasive methods require at least partially restrained research subjects, and they only allow identification of large numbers of simultaneously activated neurons. On the other hand, small ensembles of neurons or individual neurons can only be measured using single-cell recordings obtained from largely reduced preparations. Since the expression of natural behavior is limited in restrained and dissected animals, the underlying neural mechanisms that control such behavior are difficult to identify. 
Here, I present a non-invasive physiological technique that allows measuring neural circuit activation in freely behaving animals. Using a pair of wire electrodes inside a water-filled chamber, the bath electrodes record neural and muscular field potentials generated by juvenile crayfish during natural or experimentally evoked escape responses. The primary escape responses of crayfish are mediated by three different types of tail-flips which move the animals away from the point of stimulation. Each type of tail-flip is controlled by its own neural circuit; the two fastest and most powerful escape responses require activation of different sets of large &#8220;command&#8221; neurons. In combination with behavioral observations, the bath electrode recordings allow unambiguous identification of these neurons and the associated neural circuits. Thus activity of neural circuitry underlying naturally occurring behavior can be measured in unrestrained animals and in different behavioral contexts.

Non-invasive measurements of neural activity patterns in freely behaving animals are obtained by combining neurophysiological recordings with high speed videography.

自由表现动物的神经回路活化的录音

The relationship between patterns of neural activity and corresponding behavioral expression is difficult to establish in unrestrained animals. ...

生物学

Automated Rat Single-Pellet Reaching with 3-Dimensional Reconstruction of Paw and Digit Trajectories

Rodent skilled reaching is commonly used to study dexterous skills, but requires significant time and effort to implement the task and analyze the behavior. Several automated versions of skilled reaching have been developed recently. Here, we describe a version that automatically presents pellets to rats while recording high-definition video from multiple angles at high frame rates (300 fps). The paw and individual digits are tracked with DeepLabCut, a machine learning algorithm for markerless pose estimation. This system can also be synchronized with physiological recordings, or be used to trigger physiologic interventions (e.g., electrical or optical stimulation).

Rodent skilled reaching is commonly used to study dexterous skills, but requires significant time and effort to implement the task and analyze the behavior. We describe an automated version of skilled reaching with motion tracking and three-dimensional reconstruction of reach trajectories.

自动大鼠单丸到达与3维重建的爪子和数字轨迹

Rodent skilled reaching is commonly used to study dexterous skills, but requires significant time and effort to implement the task and analyze the ...

Cardiac Muscle-cell Based Actuator and Self-stabilizing Biorobot - PART 1

Biological machines often referred to as biorobots, are living cell- or tissue-based devices that are powered solely by the contractile activity of living components. Due to their inherent advantages, biorobots are gaining interest as alternatives to traditional fully artificial robots. Various studies have focused on harnessing the power of biological actuators, but only recently studies have quantitatively characterized the performance of biorobots and studied their geometry to enhance functionality and efficiency. Here, we demonstrate the development of a self-stabilizing swimming biorobot that can maintain its pitch, depth, and roll without external intervention. The design and fabrication of the PDMS scaffold for the biological actuator and biorobot followed by the functionalization with fibronectin is described in this first part. In the second part of this two-part article, we detail the incorporation of cardiomyocytes and characterize the biological actuator and biorobot function. Both incorporate a base and tail (cantilever) which produce fin-based propulsion. The tail is constructed with soft lithography techniques using PDMS and laser engraving. After incorporating the tail with the device base, it is functionalized with a cell adhesive protein and seeded confluently with cardiomyocytes. The base of the biological actuator consists of a solid PDMS block with a central glass bead (acts as a weight). The base of the biorobot consists of two composite PDMS materials, Ni-PDMS and microballoon-PDMS (MB-PDMS). The nickel powder (in Ni-PDMS) allows magnetic control of the biorobot during cells seeding and stability during locomotion. Microballoons (in MB-PDMS) decrease the density of MB-PDMS, and enable the biorobot to float and swim steadily. The use of these two materials with different mass densities, enabled precise control over the weight distribution to ensure a positive restoration force at any angle of the biorobot. This technique produces a magnetically controlled self-stabilizing swimming biorobot.

In this two-part study, a biological actuator was developed using highly flexible polydimethylsiloxane (PDMS) cantilevers and living muscle cells (cardiomyocytes), and characterized. The biological actuator was incorporated with a base made of modified PDMS materials to build a self-stabilizing, swimming biorobot.

心肌肌细胞基致动器和自稳定Biorobot  - 第1部分

Biological machines often referred to as biorobots, are living cell- or tissue-based devices that are powered solely by the contractile activity of living ...

生物工程

Flapping Soft Fin Deformation Modeling using Planar Laser-Induced Fluorescence Imaging

Propulsive mechanisms inspired by the fins of various fish species have been increasingly researched, given their potential for improved maneuvering and stealth capabilities in unmanned vehicle systems. Soft materials used in the membranes of these fin mechanisms have proven effective at increasing thrust and efficiency compared with more rigid structures, but it is essential to measure and model the deformations in these soft membranes accurately. This study presents a workflow for characterizing the time-dependent shape deformation of flexible underwater flapping fins using planar laser-induced fluorescence (PLIF). Pigmented polydimethylsiloxane fin membranes with varying stiffnesses (0.38 MPa and 0.82 MPa) are fabricated and mounted to an assembly for actuation in two degrees of freedom: pitch and roll. PLIF images are acquired across a range of spanwise planes, processed to obtain fin deformation profiles, and combined to reconstruct time-varying 3D deformed fin shapes. The data are then used to provide high-fidelity validation for fluid-structure interaction simulations and improve the understanding of the performance of these complex propulsion systems.

The present protocol involves the measurement and characterization of 3D shape deformation in underwater flapping fins built with polydimethylsiloxane (PDMS) materials. Accurate reconstruction of these deformations is essential for understanding the propulsive performance of compliant flapping fins.

基于平面激光诱导荧光成像的拍打软鳍变形建模

Propulsive mechanisms inspired by the fins of various fish species have been increasingly researched, given their potential for improved maneuvering and ...