Auditory responses in the cochlear nucleus of awake mustached bats: Precursors to spectral integration in the auditory midbrain
Auditory responses in the cochlear nucleus of awake mustached bats: Precursors to spectral integration in the auditory midbrain
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DOI：
10.1152/jn.00634.2005
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发表时间：
2006-01-01
影响因子：
2.5
通讯作者：
Wenstrup, JJ
中科院分区：
文献类型：
--
作者：
Marsh, RA;Nataraj, K;Wenstrup, JJ
在耳蜗核（CN）清醒的胡子蝙蝠，单，双音刺激被用来研究如何在主要CN分区的反应有助于在下丘（IC）的spectrotemporal整合功能。在CN各分区中，频率的比例代表性不同。一个惊人的结果是大量的单位调谐到频率< 23千赫。在不同频段，时间响应模式，潜伏期和自发放电不同。例如，23- 30-kHz的代表，其中包括声纳呼叫的基本，有一个不寻常的高比例的单位与起始反应（39%）和低自发率（53%）。调谐到58-59 kHz的单位，对应于急剧调谐的耳蜗共振，具有比其他频带稍长但明显更长的低频。在频率> 30 kHz的单位中，31%显示出第二个兴奋峰，通常在10和22 kHz之间。对于某些单位，次级峰可能起源于耳蜗机制，但在其他单位中，它可能是由CN神经元上的会聚输入引起的。在20%的单位测试与双音刺激，抑制最佳频率（BF）的反应被调谐至少一个八度以下BF。这些特性可能是类似IC响应的基础。然而，其他形式的光谱相互作用存在于IC中不存在于CN中：我们发现没有促进组合敏感的相互作用和非常少的组合敏感的抑制性相互作用的主导IC类型，其中抑制被调谐到23-30 kHz。这种相互作用出现在CN之上。因此，不同形式的频谱整合起源于上行听觉通路的不同层次。
In the cochlear nucleus (CN) of awake mustached bats, single- and two-tone stimuli were used to examine how responses in major CN subdivisions contribute to spectrotemporal integrative features in the inferior colliculus (IC). Across CN subdivisions, the proportional representation of frequencies differed. A striking result was the substantial number of units tuned to frequencies < 23 kHz. Across frequency bands, temporal response patterns, latency, and spontaneous discharge differed. For example, the 23- to 30-kHz representation, which comprises the fundamental of the sonar call, had an unusually high proportion of units with onset responses (39%) and low spontaneous rates (53%). Units tuned to 58-59 kHz, corresponding to the sharply tuned cochlear resonance, had slightly but significantly longer latencies than other bands. In units tuned to frequencies > 30 kHz, 31% displayed a secondary excitatory peak, usually between 10 and 22 kHz. The secondary peak may originate in cochlear mechanisms for some units, but in others it may result from convergent input onto CN neurons. In 20% of units tested with two-tone stimuli, suppression of best frequency (BF) responses was tuned at least an octave below BF. These properties may underlie similar IC responses. However, other forms of spectral interaction present in IC were absent in CN: we found no facilitatory combination-sensitive interactions and very few combination-sensitive inhibitory interactions of the dominant IC type in which inhibition was tuned to 23-30 kHz. Such interactions arise above CN. Distinct forms of spectral integration thus originate at different levels of the ascending auditory pathway.