Kostarakos Konstantinos, Römer Heiner
Institute of Zoology, University of Graz, Universitaetsplatz 2, 8010, Graz, Austria.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2018 Apr;204(4):353-367. doi: 10.1007/s00359-018-1251-7. Epub 2018 Feb 19.
Males of the katydid Sphagniana sphagnorum maintain inter-male distances from one another using agonistic song interactions with a frequency-modulated song that consists of alternating audio and ultrasonic parts. We studied the neuronal representation of this song in auditory receptors and interneurons of receivers, using playbacks of songs that mimicked the absolute and relative sound pressure levels of the two song modes varying with distance. The tuning and sensitivity of both receptors and interneurons strongly determine their responses to the two song modes at different distances. Low-frequency interneurons respond preferentially to the audio mode of the song at larger distances. High-frequency (HF) interneurons respond preferentially to the HF component of the song at close range. 'Switch interneurons' are sensitive to both spectral song components, but exhibit a typical activity switch towards the high-frequency mode at distances nearer than 3-6 m. The activity of the latter two groups of interneurons correlates with the distance in the field at which males begin to interact acoustically with their neighbours. Important information about the rate of changes in the song mode is represented by the afferent activity despite the influence of the masking song produced by a sympatric katydid species.
泥炭藓叶螽的雄性个体通过发出由音频和超声波部分交替组成的调频鸣声，进行争斗性鸣声互动，以此来保持彼此之间的雄性间距。我们使用模仿两种鸣声模式的绝对和相对声压水平随距离变化的鸣声回放，研究了这种鸣声在听觉感受器和接收者中间神经元中的神经表征。感受器和中间神经元的调谐和敏感性在很大程度上决定了它们在不同距离对两种鸣声模式的反应。低频中间神经元在较远的距离优先对鸣声的音频模式做出反应。高频（HF）中间神经元在近距离优先对鸣声的高频成分做出反应。“转换中间神经元”对鸣声的两种频谱成分都敏感，但在距离小于3-6米时，会表现出向高频模式的典型活动转换。后两组中间神经元的活动与雄性个体在野外开始与邻居进行声学互动的距离相关。尽管有同域叶螽物种产生的掩蔽鸣声的影响，但传入活动仍代表了关于鸣声模式变化速率的重要信息。
