Processing of fast amplitude modulations in bat auditory cortex matches communication call-specific sound features
Processing of fast amplitude modulations in bat auditory cortex matches communication call-specific sound features
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DOI：
10.1152/jn.00748.2018
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发表时间：
2019-04-01
影响因子：
2.5
通讯作者：
Firzlaff, Uwe
中科院分区：
文献类型：
--
作者：
Hoerpel, Stephen Gareth;Firzlaff, Uwe
蝙蝠使用大量的叫声进行社会交流。在蝙蝠Phyllostomus discolor，社会通信呼叫的特点往往是正弦振幅和频率调制的调制频率在100-130赫兹的范围内。然而，哺乳动物听觉皮层调制传递函数的峰值通常限于低于100 Hz的调制频率。通过构建频率和时间调制传递函数，研究了变色龙听皮层神经元对正弦振幅调制声音的编码。此外，还记录了神经元对回放各种通信呼叫的反应，并与神经元对正弦振幅调制声音的反应进行了比较。听觉皮层后背场的皮层神经元被调谐到异常高的调制频率：速率调制传递函数通常在130 Hz左右达到峰值（中位数：87 Hz），引起显著锁相的最高调制频率的中位数也是130 Hz。这两个值都远高于其他哺乳动物的听觉皮层，超过51%的单位更喜欢调制频率超过100赫兹。显然，神经元偏好的快速调制与变色拟步行虫亲社会性（主要是攻击性）通信呼叫的快速幅度和频率调制相匹配。我们认为，在P. discolor背侧听觉皮层的快速幅度调制的偏好，可靠地编码的快速调制中看到他们的通信calls.NEW &值得注意的时间声音功能的神经处理是至关重要的通信呼叫的分析。在蝙蝠中，这些呼叫的特点往往是快速的时间包络调制。由于听觉皮层神经元通常只编码低调制频率，目前还不清楚物种特异性发声是如何处理的。我们发现，听觉皮层神经元的蝙蝠Phyllostomus变色编码快速的时间包络调制。这种特性提高了对通信呼叫的响应特异性，因此可能支持物种特异性通信。
Bats use a large repertoire of calls for social communication. In the bat Phyllostomus discolor, social communication calls are often characterized by sinusoidal amplitude and frequency modulations with modulation frequencies in the range of 100-130 Hz. However, peaks in mammalian auditory cortical modulation transfer functions are typically limited to modulation frequencies below 100 Hz. We investigated the coding of sinusoidally amplitude modulated sounds in auditory cortical neurons in P. discolor by constructing rate and temporal modulation transfer functions. Neuronal responses to playbacks of various communication calls were additionally recorded and compared with the neurons' responses to sinusoidally amplitude-modulated sounds. Cortical neurons in the posterior dorsal field of the auditory cortex were tuned to unusually high modulation frequencies: rate modulation transfer functions often peaked around 130 Hz (median: 87 Hz), and the median of the highest modulation frequency that evoked significant phase-locking was also 130 Hz. Both values are much higher than reported from the auditory cortex of other mammals, with more than 51% of the units preferring modulation frequencies exceeding 100 Hz. Conspicuously, the fast modulations preferred by the neurons match the fast amplitude and frequency modulations of prosocial, and mostly of aggressive, communication calls in P. discolor. We suggest that the preference for fast amplitude modulations in the P. discolor dorsal auditory cortex serves to reliably encode the fast modulations seen in their communication calls.NEW & NOTEWORTHY Neural processing of temporal sound features is crucial for the analysis of communication calls. In bats, these calls are often characterized by fast temporal envelope modulations. Because auditory cortex neurons typically encode only low modulation frequencies, it is unclear how species-specific vocalizations are cortically processed. We show that auditory cortex neurons in the bat Phyllostomus discolor encode fast temporal envelope modulations. This property improves response specificity to communication calls and thus might support species-specific communication.