Dataset for: Processing of interaural phase differences in components of harmonic and mistuned complexes in the inferior colliculus of the Mongolian gerbil

Harmonicity as well as spatial location provide eminent cues for the perceptual grouping of sounds. In general, harmonicity is a strong grouping cue. In contrast, spatial cues such as interaural phase or time difference provide for strong grouping of stimulus sequences but weak grouping for simultaneously presented sounds. By studying the neuronal basis underlying the interaction of these cues in processing simultaneous sounds using van Rossum spike train distance measures, we aim at explaining the interaction observed in psychophysical experiments. Responses to interaural phase differences imposed on single components of harmonic and mistuned complex tones as well as noise delay functions were recorded as multiunit responses from the inferior colliculus of Mongolian gerbils. Results revealed a better representation of interaural phase differences if imposed on a harmonic rather than a mistuned frequency component of a complex tone. The representation of interaural phase differences was better for long integration-time windows approximately reflecting firing rates rather than short integration-time windows reflecting the temporal pattern of the stimulus-driven response. We found only a weak impact of interaural phase differences if combined with mistuning of a component in a harmonic tone complex.

和声性（harmonicity）与空间位置均可为声音的知觉分组（perceptual grouping）提供显著线索。一般而言，和声性是一种强有力的分组线索。与之相对，耳间相位差（interaural phase difference）或时间差等空间线索可对刺激序列形成强分组效应，但对同时呈现的声音仅产生弱分组效果。本研究借助范罗森峰电位序列距离（van Rossum spike train distance）分析法，探究同时呈现声音加工中这些线索交互作用的神经基础，旨在解释心理物理实验中观测到的交互效应。研究记录了蒙古沙鼠（Mongolian gerbils）下丘（inferior colliculus）的多单位反应（multiunit responses），该响应对应于对和声复合音与失谐复合音的单个成分施加耳间相位差，以及噪声延迟函数时的神经活动。实验结果显示，相较于对失谐的复合音频率成分施加耳间相位差，当耳间相位差施加于和声复合音的成分时，其耳间相位差的神经表征更为清晰。此外，相较于反映刺激驱动响应时间模式的短整合时间窗，长整合时间窗（其近似对应放电率（firing rates））下的耳间相位差表征效果更优。我们发现，当耳间相位差与和声复合音的某一成分失谐相结合时，其对神经响应的影响仅表现为微弱的改变。