Durr Volker, Matheson Thomas
Abteilung für Biologische Kybernetik und Theoretische Biologie, Fakultät für Biologie, Universität Bielefeld, D-33501 Bielefeld, Germany.
J Neurophysiol. 2003 Sep;90(3):1754-65. doi: 10.1152/jn.00416.2003. Epub 2003 May 28.
Grooming responses are movements of a multi-jointed limb that are targeted toward a stimulus site on the body. To be successful, they require a continuous transformation of stimulus location into a corresponding motor pattern or selection and blending of a subset of cardinal motor patterns. Tactile stimulation of one forewing of a locust elicits characteristic grooming movements of the ipsilateral hind leg. An initial targeted trajectory that moves the tarsus toward the site of stimulation is followed by a cyclic trajectory in the region of the stimulus. We have analyzed both components of this behavior to quantify the relative effects of somatotopic stimulus position and leg start posture on three parameters: initial movement direction, accuracy, and grooming distribution. Accuracy and grooming distribution were significantly affected by the stimulus location but were not influenced by the initial leg posture. Both cues systematically shifted the initial movement direction from the onset of the response. The subsequent cyclic component of grooming movements forms a behavioral continuum with no clustering in joint angle space. We therefore conclude that forewing grooming in locusts is generated by a single movement pattern that is continuously shifted by a sensory cue signaling position on the forewing surface. Both vertebrates and invertebrates can switch between distinct movement forms to groom different parts of their bodies. Our data provide the first evidence that invertebrates, like vertebrates, also have graded control of limb targeting within the somatosensory receptive field of a single form of motor response.
梳理反应是多关节肢体朝向身体上刺激部位的运动。要成功完成梳理反应，需要将刺激位置持续转换为相应的运动模式，或者选择并组合基本运动模式的一个子集。对蝗虫一只前翅进行触觉刺激会引发同侧后腿的特征性梳理运动。最初将跗节移向刺激部位的目标轨迹之后是刺激区域内的循环轨迹。我们分析了这种行为的两个组成部分，以量化躯体感觉刺激位置和腿部起始姿势对三个参数的相对影响：初始运动方向、准确性和梳理分布。准确性和梳理分布受刺激位置的显著影响，但不受腿部初始姿势的影响。这两个线索都系统地改变了反应开始时的初始运动方向。梳理运动随后的循环部分形成了一个行为连续体，在关节角度空间中没有聚类。因此，我们得出结论，蝗虫的前翅梳理是由单一运动模式产生的，该模式通过前翅表面位置的感觉线索不断变化。脊椎动物和无脊椎动物都可以在不同的运动形式之间切换，以梳理身体的不同部位。我们的数据提供了首个证据，表明无脊椎动物与脊椎动物一样，在单一运动反应形式的躯体感觉感受野内，对肢体定位也有分级控制。
