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).