Animal Physiology and Behavior Group, Department for Neuroscience, School for Medicine and Health Sciences, Carl-von-Ossietzky University Oldenburg, 26111, Oldenburg, Germany.
Cluster of Excellence Hearing4all, Carl-von-Ossietzky University Oldenburg, 26111, Oldenburg, Germany.
Eur J Neurosci. 2018 May;47(10):1242-1251. doi: 10.1111/ejn.13922. Epub 2018 Apr 16.
Harmonicity and 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.
和谐度和空间位置为声音的知觉分组提供了显著的线索。一般来说，和谐度是一个很强的分组线索。相比之下，空间线索，如两耳间相位或时间差，为刺激序列的强分组提供了条件，但对同时呈现的声音的分组作用较弱。通过使用 van Rossum 尖峰时间距离测量来研究这些线索在处理同时呈现的声音时相互作用的神经基础，我们旨在解释在心理物理实验中观察到的相互作用。记录了来自蒙古沙鼠下丘的多单位反应，以研究施加于谐波和失谐复音的单个分量以及噪声延迟函数的两耳间相位差对响应的影响。结果表明，如果施加于复音的谐波分量而不是失谐频率分量，那么两耳间相位差的表示会更好。对于大约反映放电率的长积分时间窗口，而不是反映刺激驱动响应的时间模式的短积分时间窗口，对两耳间相位差的表示更好。如果将其与谐波音复合体中的一个分量的失谐相结合，则发现两耳间相位差的影响很弱。
