Different Tonotopic Regions of the Lateral Superior Olive Receive a Similar Combination of Afferent Inputs
Different Tonotopic Regions of the Lateral Superior Olive Receive a Similar Combination of Afferent Inputs
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DOI：
10.1002/cne.23942
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发表时间：
2016-08-01
影响因子：
2.5
通讯作者：
Saldana, Enrique
中科院分区：
文献类型：
--
作者：
Gomez-Alvarez, Marcelo;Saldana, Enrique
哺乳动物的侧上橄榄（LSO）通过整合同侧兴奋和对侧抑制来编码到达两耳的声音强度的差异，但目前尚不清楚是哪种特定的神经元类型将声音信息传递给细胞核。也不确定已知的明显的形态功能差异和沿LSO同质轴的梯度是否与传入神经的定性和/或定量区域差异有关。为了澄清这些问题，我们将生物素化右旋糖酐胺（BDA）的神经解剖示踪剂注射到白化大鼠LSO的不同tonote区域，并分析了脑干听核逆行标记的神经元。我们发现，LSO受四种脑干神经元类型的局部神经支配：同侧耳蜗腹侧核的球形丛状细胞和平面多极神经元，同侧梯形体内侧核的主神经元，以及对侧梯形体腹侧核的小多极神经元。出乎意料的是，在所有情况下，每种类型的标记神经元的比例几乎相同，这表明LSO的所有张力区域都接受了相似的输入组合。更令人惊讶的是，我们的数据还表明，LSO中的频率表示与支配它的核的频率表示不同：与后一种核相比，LSO似乎拥有相对较大的体积用于处理频谱中低部分的频率，而相对较小的部分用于处理高频。(C) 2015 Wiley期刊公司
The mammalian lateral superior olive (LSO) codes disparities in the intensity of the sound that reaches the two ears by integrating ipsilateral excitation and contralateral inhibition, but it remains unclear what particular neuron types convey acoustic information to the nucleus. It is also uncertain whether the known conspicuous morphofunctional differences and gradients along the tonotopic axis of the LSO relate to qualitative and/or quantitative regional differences in its afferents. To clarify these issues, we made small, single injections of the neuroanatomical tracer biotinylated dextran amine (BDA) into different tonotopic regions of the LSO of albino rats and analyzed the neurons labeled retrogradely in brainstem auditory nuclei. We demonstrate that the LSO is innervated tonotopically by four brainstem neuron types: spherical bushy cells and planar multipolar neurons of the ipsilateral ventral cochlear nucleus, principal neurons of the ipsilateral medial nucleus of the trapezoid body, and small multipolar neurons of the contralateral ventral nucleus of the trapezoid body. Unexpectedly, the proportion of labeled neurons of each type was virtually identical in all cases, thus indicating that all tonotopic regions of the LSO receive a similar combination of inputs. Even more surprisingly, our data also suggest that the representation of frequencies in the LSO differs from that of the nuclei that innervate it: compared to the latter nuclei, the LSO seems to possess a relatively larger portion of its volume devoted to processing frequencies in the lower-middle part of the spectrum, and a relative smaller portion devoted to higher frequencies. (C) 2015 Wiley Periodicals, Inc.