Quantification of gait parameters in freely walking wild type and sensory deprived Drosophila melanogaster.
Quantification of gait parameters in freely walking wild type and sensory deprived Drosophila melanogaster.
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DOI：
10.7554/elife.00231
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发表时间：
2013-01-08
期刊：
影响因子：
7.7
通讯作者：
Mann RS
中科院分区：
文献类型：
--
作者：
Mendes CS;Bartos I;Akay T;Márka S;Mann RS
脊椎动物和多足无脊椎动物（如黑腹果蝇）的协调行走需要一个复杂的神经网络与感觉反馈耦合。对这个网络的理解将受益于果蝇等具有遗传操纵神经活动能力的系统。然而，苍蝇的小尺寸使得在这个系统中分析行走具有挑战性。为了克服这一限制，我们开发了一种光学方法，结合高速成像，允许跟踪和量化的步态参数在自由行走的苍蝇具有高的时间和空间分辨率。使用这种方法，我们提出了一个全面的描述，许多运动参数，如步态，跗骨定位，节间和左右协调野生型果蝇。令人惊讶的是，我们发现，在苍蝇的腿感觉神经元的失活，以阻止本体感受反馈，导致缺乏步精度，但腿间协调和执行三脚架步态的能力不受影响。http://dx.doi.org/10.7554/eLife.00231.001大多数动物需要能够移动才能生存。没有四肢的动物，如蛇，通过沿着它们的身体产生波浪状收缩来移动，而有四肢的动物，如脊椎动物和节肢动物，通过协调多关节的手臂和腿的运动来行走。四肢动物的运动包括以协调的方式弯曲每个手臂或腿内的每个关节，同时还确保所有肢体的运动彼此协调。例如，在诸如人类的两足动物中，当另一条腿处于摆动阶段时，一条腿处于站立阶段是至关重要的。支配四肢协调的规则也取决于步态，因此步行的规则与跑步的规则不同。两足动物和其他行走动物的神经系统通过使用协调相关运动神经元放电的复杂神经回路来解决这些问题。两种一般机制用于协调运动神经元的放电。在一种机制中，中枢神经系统内的局部中间神经元协调运动神经元的活动：在脊椎动物中，这些中间神经元存在于脊髓中。第二种机制，称为本体感受，依赖于感觉神经元，这些感觉神经元将手臂和腿的负荷和关节角度报告回中枢神经系统，从而影响运动神经元的放电。值得注意的是，这两种机制，以及构成运动神经元回路的神经元类型，从节肢动物到脊椎动物都是保守的。门德斯等人描述了一种新的方法，可以用来分析果蝇D.黑腹动物在表面行走他们使用光学触摸传感器和高速视频成像的组合来跟踪苍蝇行走的身体，并记录它在移动时将六只脚放在表面的时间和位置。然后，使用一个名为FlyWalker的软件包，他们能够提取大量的参数，这些参数可用于描述成年果蝇的运动，具有很高的时间和空间分辨率。其中许多参数以前从未被测量或研究过。门德斯等人表明，果蝇不会表现出通常在脊椎动物中观察到的步态突然转变。然而，它们确实会根据自己的速度来修改它们的神经回路：事实上，苍蝇在慢速、中速和快速行走时使用的神经回路似乎略有不同。此外，当基因方法被用来阻止感官反馈时，苍蝇仍然能够行走，尽管协调性和精确性有所降低。此外，数据表明，当苍蝇走得更快时，本体感觉不如走得更慢时重要。这项研究的下一步将是联合收割机，将这种分析果蝇运动的新方法与可用于果蝇研究的广泛遗传工具相结合：这将使研究人员能够更详细地探索运动神经元回路的组成部分及其在协调行走中的作用。DOI：http://dx.doi.org/10.7554/eLife.00231.002网站
Coordinated walking in vertebrates and multi-legged invertebrates such as Drosophila melanogaster requires a complex neural network coupled to sensory feedback. An understanding of this network will benefit from systems such as Drosophila that have the ability to genetically manipulate neural activities. However, the fly's small size makes it challenging to analyze walking in this system. In order to overcome this limitation, we developed an optical method coupled with high-speed imaging that allows the tracking and quantification of gait parameters in freely walking flies with high temporal and spatial resolution. Using this method, we present a comprehensive description of many locomotion parameters, such as gait, tarsal positioning, and intersegmental and left-right coordination for wild type fruit flies. Surprisingly, we find that inactivation of sensory neurons in the fly's legs, to block proprioceptive feedback, led to deficient step precision, but interleg coordination and the ability to execute a tripod gait were unaffected. DOI: http://dx.doi.org/10.7554/eLife.00231.001 Most animals need to be able to move to survive. Animals without limbs, such as snakes, move by generating by wave-like contractions along their bodies, whereas limbed animals, such as vertebrates and arthropods, walk by coordinating the movements of multi-jointed arms and legs. Locomotion in limbed animals involves bending each joint within each arm or leg in a coordinated manner, while also ensuring that the movements of all the limbs are coordinated with each other. In bipeds such as humans, for example, it is critical that one leg is in the stance phase when the other leg is in the swing phase. The rules that govern the coordination of limbs also depend on the gait, so the rules for walking are not the same as the rules for running. The nervous systems of bipeds and other animals that walk solve these problems by using complex neural circuits that coordinate the firing of the relevant motor neurons. Two general mechanisms are used to coordinate the firing of motor neurons. In one mechanism, local interneurons within the central nervous system coordinate motor neuron activities: in vertebrates these interneurons are found in the spinal cord. A second mechanism, termed proprioception, relies on sensory neurons that report the load and joint angles from the arms and legs back to the central nervous system, and thereby influence the firing of the motor neurons. Remarkably, both of these mechanisms, and also the types of neurons that comprise motor neuron circuits, are conserved from arthropods to vertebrates. Mendes et al. describe a new approach that can be used to analyze how the fruit fly, D. melanogaster, walks on surfaces. They use a combination of an optical touch sensor and high-speed video imaging to follow the body of the fly as it walks, and also to record when and where it places each of its six feet on the surface as it moves. Then, using a software package called FlyWalker, they are able to extract a large of number of parameters that can be used to describe locomotion in adult fruit flies with high temporal and spatial resolution. Many of these parameters have never been measured or studied before. Mendes et al. show that fruit flies do not display the abrupt transitions in gait that are typically observed in vertebrates. However, they do modify their neural circuits depending on their speed: indeed it appears that flies use subtly different neural circuitry for walking at slow, medium and fast speeds. Moreover, when genetic methods are used to block sensory feedback, the fly is still able to walk, albeit with reduced coordination and precision. Further, the data suggest that proprioception is less important when flies walk faster compared to when they walk more slowly. The next step in this research will be to combine this new method for analyzing locomotion in flies with the wide range of genetic tools that are available for the study of Drosophila: this will allow researchers to explore in greater detail the components of the motor neuron circuitry and their role in coordinated walking. DOI: http://dx.doi.org/10.7554/eLife.00231.002