Motor control of auditory steering in crickets

神经科学在理解神经元和神经元网络的功能方面取得了巨大进展。对运动系统或感觉通路的分析揭示了动物如何产生运动模式或处理来自环境的感觉信息的基本原理。然而，感觉-运动接口（sensory-to-motor interfaces），即处理感觉信号并产生适当运动命令的中枢神经系统网络，很少被研究，因为重点是运动系统或感觉系统。该项目的目的是考虑这两个方面，并分析潜在的听觉诱发的女性蟋蟀转向反应的运动活动。这些动物利用雄性的叫声来定位唱歌的雄性。在神经生物学中，它们是多年来分析听觉处理神经机制的模型系统。蟋蟀听觉通路的神经元被很好地描述了，我们对动物在神经系统的早期阶段如何处理声音模式有了很好的理解。然而，我们仍然缺乏关键的信息，他们如何真正认识到男性的呼唤歌曲，以及他们如何设法转向唱歌的伴侣。在许多以前的实验中，听觉处理通常是在被限制的动物中进行分析的。在这些实验中，没有迹象表明感觉信号是否被识别并产生适当的运动命令。在我们的实验中，被拴着的蟋蟀将在轨迹球上行走，并将朝着一个声音模式转向。因此，该项目将通过监测动物的行走行为来克服以前方法的基本实验问题。这将是一个可靠的指标，趋声性引起的，相应的处理听觉信号已经启动。这对于我们的方法来证明和理解神经元到运动通路的神经机制至关重要。与行走行为一起，我们将记录特定运动神经元和中间神经元的活动，这些神经元控制前腿的转向运动。这些实验将告诉我们，什么样的听觉诱发命令从大脑发送到运动神经元，以控制转向运动。他们还将展示听觉模式识别过程如何将听觉中间神经元的反应转化为控制腿部运动的运动命令。分析这个模型系统将揭示听觉处理的原理，并将有助于行为神经科学的一个关键目标，即了解从感觉处理到运动模式生成的动物行为的神经组织。

Neuroscience has made enormous progress in understanding the function of neurons and neuronal networks. The analysis of motor systems or sensory pathways has revealed fundamental principles of how animals generate motor patterns or process sensory information from their environment. However, sensory-to-motor interfaces, the networks of the central nervous system where sensory signals are processed and appropriate motor commands are generated, have rarely been studied, as the focus is either on motor systems or on sensory systems. The aim of the project is to consider both aspects and to analyse the motor activity underlying auditory evoked steering responses in female crickets. These animals orient towards singing males using the male's calling song for orientation. In neurobiology they are model systems for analysing the neural mechanisms of auditory processing since many years. The neurons of the cricket auditory pathway are well described and we have a very good understanding, how the animals process sound patterns at the early stages of their nervous system. However, we still lack the crucial information, how they actually recognise the calling songs of the males and how they then manage to steer towards the singing mate. In many previous experiments auditory processing was generally analysed in restrained animals. In those experiments there was no indication, if the sensory signals were recognised and appropriate motor commands were generated. In our experiments tethered crickets will be walking on a trackball and will steer towards a sound pattern. The project will therefore overcome a fundamental experimental problem of previous approaches by monitoring the walking behaviour of the animals. This will be a reliable indicator that phonotaxis is elicited and that the corresponding processing of auditory signals has been initiated. This is crucial for our approach to demonstrate and understand the neural mechanisms underlying the auditory-to-motor pathway. Together with the walking behaviour we will record the activity of specific motoneurons, and interneurons, which control the steering movements of the front legs. These experiments will tell us, what type of auditory evoked commands are send to the motoneurons from the brain, in order to control the steering movements. They will also demonstrate how an auditory pattern recognition process, transforms responses of auditory interneurons into motor commands controlling leg movements. Analysing this model system will reveal principles of auditory processing and will contribute to a pivotal aim of behavioural neuroscience that is to understand the neural organisation of animal behaviour from sensory processing to motor pattern generation.