Abnormal auditory experience induces frequency-specific adjustments in unit tuning for binaural localization cues in the optic tectum of juvenile owls
Abnormal auditory experience induces frequency-specific adjustments in unit tuning for binaural localization cues in the optic tectum of juvenile owls
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DOI：
10.1523/jneurosci.20-02-00862.2000
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发表时间：
2000-01-15
影响因子：
5.3
通讯作者：
Knudsen, EI
中科院分区：
文献类型：
--
作者：
Gold, JI;Knudsen, EI
早期的听觉经验以一种频率依赖的方式塑造了谷仓猫头鹰视顶盖神经元的听觉空间调谐。我们考察了这种适应性可塑性的基础，根据频率特定的耳间时间差(ITD)和水平差异(ILDS)的调谐变化，这是主要的声音定位线索。我们对正常猫头鹰和单耳饲养的猫头鹰的宽带和窄带ITD和ILD调谐进行了研究，这些猫头鹰的单耳声学过滤装置会导致声音时序和声级的频率依赖变化。在正常猫头鹰中，单位被调谐到特定频率的ITD和ILD值，这些值与位于其视觉接受野的声源产生的值相匹配。相比之下，在设备饲养的猫头鹰中，对于4 kHz的刺激，大多数部位的ITD调谐从正常向开耳导联移动了约55µs，对于8 kHz的刺激，ITD向对侧耳导联的方向移动了15mU秒，反映了设备的声学效应。ILD调谐在自适应方向上的漂移与4 kHz刺激时的3分贝和8 kHz刺激时的8分贝相似，但根据设备的声学效应，这些漂移比预期的要小得多。大多数部位也表现出明显的频率反应功能异常，包括对刺激ITD的强烈依赖，以及对6 kHz刺激的正常强健反应减少。结果表明，视顶盖高阶听神经元的反应特性在发育过程中被调整，以反映个体经历的双耳定位线索的频率特定特征的影响。
Early auditory experience shapes the auditory spatial tuning of neurons in the barn owl's optic tectum in a frequency-dependent manner. We examined the basis for this adaptive plasticity in terms of changes in tuning for frequency-specific interaural time differences (ITDs) and level differences (ILDs), the dominant sound localization cues. We characterized broadband and narrowband ITD and ILD tuning in normal owls and in owls raised with an acoustic filtering device in one ear that caused frequency-dependent changes in sound timing and level. In normal owls, units were tuned to frequency-specific ITD and ILD values that matched those produced by sound sources located in their visual receptive fields. In contrast, in device-reared owls, ITD tuning at most sites was shifted from normal by similar to 55 mu sec toward open-ear leading for 4 kHz stimuli and 15 mu sec toward the opposite-ear leading for 8 kHz stimuli, reflecting the acoustic effects of the device. ILD tuning was shifted in the adaptive direction by similar to 3 dB for 4 kHz stimuli and 8 dB for 8 kHz stimuli, but these shifts were substantially smaller than expected based on the acoustic effects of the device. Most sites also exhibited conspicuously abnormal frequency- response functions, including a strong dependence on stimulus ITD and a reduction of normally robust responses to 6 kHz stimuli. The results demonstrate that the response properties of high-order auditory neurons in the optic tectum are adjusted during development to reflect the influence of frequency- specific features of the binaural localization cues experienced by the individual.