Data from: Developmental fine-tuning of MSO neurons mitigates their predisposition to contralateral sound sources

ABSTRACT. Having two ears enables us to localize sound sources by exploiting interaural time differences (ITDs) in sound arrival. Principal neurons of the medial superior olive (MSO) are sensitive to ITD, and each MSO neuron responds optimally to a best ITD (bITD). In many cells, especially those tuned to low sound frequencies, these bITDs correspond to ITDs for which the contralateral ear leads, and are often larger than the ecologically relevant range, defined by the ratio of the interaural distance and the speed of sound. Using in vivo recordings in gerbils, we found that shortly after hearing onset the bITDs were even more contralaterally leading than found in adult gerbils, and travel latencies for contralateral sound-evoked activity clearly exceeded those for ipsilateral sounds. During the following weeks, both these latencies and their interaural difference decreased. A computational model indicated that spike timing-dependent plasticity can underlie this fine-tuning. Our results suggest that MSO neurons start out with a strong predisposition toward contralateral sounds due to their longer neural travel distances, but that, especially in high-frequency neurons, this predisposition is subsequently mitigated by differential developmental fine-tuning of the travel latencies. This repository includes the in vivo recordings of MSO cells in Mongolian gerbils and the code for the simulation of spike timing-dependent development. Filenames (e.g. MG211015a_U24_BINZW) indicate the recording date (MG/*YYYYMMDD/*), which gerbil (a/b), the recorded unit (U#), and the sound stimulus (BINZW: binaural zwuis with different ITDs, ClickSPL: monaural clicks with different click intensities, ClickITD: binaural click with different ITDs, DZW: double zwuis presented either binaural, ipsilateral or contralateral). Recordings with spike times and stimulus information are stored in .mat-files. Visual output of the analysis can be viewed as .fig and .pdf-files. The suffix 'EPSP' in the filename indicates the analysis of the EPSP that preceded the spike. Statistics and statistical testing is available as .xlsx-file. Code for the simulations can be found as .m-file (MATLAB R2019a).摘要 双耳听觉可通过利用声音到达时的双耳时间差（interaural time differences, ITDs）实现声源定位。内侧上橄榄核（medial superior olive, MSO）的主神经元对双耳时间差具有敏感性，且每个MSO神经元均会对最优双耳时间差（best ITD, bITD）产生最佳响应。在多数神经元（尤其是对低声频率敏感的神经元）中，这类最优双耳时间差对应于对侧耳领先的双耳时间差，且其数值通常超出由双耳间距与声速之比定义的生态相关范围。通过对蒙古沙鼠的在体记录，我们发现，在听觉功能发育初期，最优双耳时间差比对成年沙鼠的观测结果更偏向对侧耳领先；且对侧声诱发活动的传导时延显著长于同侧声诱发活动。在后续的数周内，上述传导时延及其双耳间差值均出现下降。计算模型表明，脉冲时序依赖可塑性（spike timing-dependent plasticity）可作为这类精细调控的基础。我们的研究结果显示，MSO神经元最初因神经传导距离更长，表现出对侧声的强烈偏好；但尤其在高频敏感神经元中，这种偏好会随后通过传导时延的差异化发育精细调控而被削弱。 本数据集仓库包含蒙古沙鼠内侧上橄榄核神经元的在体记录数据，以及脉冲时序依赖可塑性发育模拟的代码。文件名格式（例如MG211015a_U24_BINZW）可反映以下信息：记录日期（MG_YYYYMMDD，即MG/*YYYYMMDD/*）、受试沙鼠编号（a/b）、记录单元编号（U#）以及声音刺激类型：BINZW指携带不同双耳时间差的双耳zwuis声刺激，ClickSPL指声强各异的单声咔哒刺激，ClickITD指携带不同双耳时间差的双耳咔哒刺激，DZW指以双耳、同侧或对侧方式呈现的双声zwuis刺激。包含锋电位时序与刺激信息的记录数据存储于.mat格式文件中。分析所得的可视化结果可通过.fig与.pdf格式文件查看。文件名后缀“EPSP”表示该文件针对锋电位前驱的兴奋性突触后电位（excitatory postsynaptic potential, EPSP）进行分析。统计数据与统计检验结果存储于.xlsx格式文件中。模拟代码以.m格式文件形式提供（适配MATLAB R2019a版本）。