Control of Reafference in Posture and Locomotion

抵抗反射帮助动物对抗会移动其肢体的外力，因此它们有助于保持稳定的姿势。在自主运动中，这些相同的抵抗反射必须被禁用或逆转，以允许运动发生。这项研究探讨了抵抗反射是如何组织起来，使动物保持静止的姿势，以及它们是如何在开始自主运动时被禁用并转化为辅助反射的。虽然这些问题已经在脊椎动物、昆虫和甲壳类动物中得到了解决，但答案还远远不够完整。当前研究中的问题将在小龙虾中得到解决，因为腿部运动的相关电路已经被描述为一组已识别的感觉神经元、中间神经元和运动神经元，以及它们的突触相互作用。研究者将使用三种方法：(i)体内运动分析和神经记录；（ii）体外制备/神经力学混合模型；（三）小龙虾身体和神经系统的神经力学模拟。这种方法将揭示动物是如何控制它的反射来帮助稳定姿势和协助水下和陆地上的自主运动的，这两个地方的外力是非常不同的。这里发现的机制很可能被其他有腿的动物使用。该方法采用了由首席研究员实验室开发的两种新工具，AnimatLab神经力学模拟软件和将模型与实验准备的神经系统连接起来的混合神经力学接口。AnimatLab可以在www.animatlab.com上免费获得，混合接口将被制成商业级电子仪器。这项研究将为本科生和研究生提供神经生理学、行为分析和计算神经科学方面的培训，其中包括代表性不足的人群。这些学生将参与乔治亚州立大学为来自全国各地的优秀本科生开设的夏季B.R.A.I.N.课程的相关教学。

Resistance reflexes help an animal to counter external forces that would move its limbs, thus they help maintain a stable posture. During voluntary movement, those same resistance reflexes must be disabled or reversed to allow the movement to occur. This study asks how the resistance reflexes are organized to allow an animal to maintain a static posture, and how they are disabled and transformed into assistance reflexes at the onset of voluntary movements. While these questions have been approached in vertebrates, insects and crustaceans, answers are far from complete. The questions in the current study will be addressed in the crayfish because relevant circuitry for leg movements has been described in terms of a set of identified sensory neurons, interneurons and motor neurons, and their synaptic interactions. The investigators will use three approaches: (i) in vivo motion analysis and nerve recordings; (ii) a hybrid in vitro preparation/neuromechanical model; and (iii) a neuromechanical simulation of the crayfish body and nervous system. This approach will reveal how the animal controls its reflexes to help stabilize posture and assist voluntary movements underwater and on land, where the set of external forces are very different. The mechanisms discovered here are likely to be used by other legged animals. The approach employs two new tools developed by the principal investigator's laboratory, the AnimatLab neuromechanical simulation software and the hybrid neuromechanical interface that links a model to the nervous system of the experimental preparation. AnimatLab is freely available at www.animatlab.com, and the hybrid interface will be made into a commercial-grade electronic instrument. The research will provide training in neurophysiology, behavioral analysis and computational neuroscience to undergraduate and graduate students who include members of underrepresented populations. Those students will participate in helping to teach relevant portions of the summer B.R.A.I.N. course at Georgia State University for outstanding undergraduates from around the country.