Tonotopic distribution and inferior colliculus projection pattern of inhibitory and excitatory cell types in the lateral superior olive of mice.
Tonotopic distribution and inferior colliculus projection pattern of inhibitory and excitatory cell types in the lateral superior olive of mice.
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小鼠外侧上橄榄抑制性和兴奋性细胞类型的音位分布和下丘投射模式。
DOI：
10.1002/cne.25515
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Winters,BradleyD
中科院分区：
文献类型：
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作者：
Haragopal,Hariprakash;Mellott,JeffreyG;Dhar,Matasha;Kanel,Alinea;Mafi,Amir;Tokar,Nick;Winters,BradleyD
外侧上级橄榄核（LSO）的主要神经元（PN）是哺乳动物脑干回路的重要组成部分，比较两耳之间的活动，并提取用于声音定位的强度和时间差异。有两种LSO PN递质类型，甘氨酸能和谷氨酸能，它们也具有不同的向下丘（IC）的上行投射模式。甘氨酸能LSO PN同侧投射，而谷氨酸能LSO PN的投射因物种而异。在具有良好低频听力（<3 kHz）的动物（如猫和沙鼠）中，听觉能LSO PN具有同侧和对侧投射;然而，缺乏这种能力的大鼠只有对侧通路。此外，在沙鼠中，脑干同侧投射LSO PN偏向LSO的低频分支，表明该通路可能是对低频听力的适应。为了进一步验证这一前提，我们通过结合原位杂交和逆行示踪剂注射，使用小鼠检查了另一种高频特化物种中LSO PN的分布和IC投射模式。我们观察到甘氨酸能和谷氨酸能LSO PN之间没有重叠，证实它们在小鼠中也是不同的细胞群。我们发现，小鼠也缺乏同侧的LSO到IC的神经元投射，并且它们的LSO PN类型没有表现出明显的tonotopic偏见。这些数据提供了对上级橄榄复合体的细胞组织及其向更高处理中心的输出的见解，这可能是信息功能分离的基础。
The principal neurons (PNs) of the lateral superior olive nucleus (LSO) are an important component of mammalian brainstem circuits that compare activity between the two ears and extract intensity and timing differences used for sound localization. There are two LSO PN transmitter types, glycinergic and glutamatergic, which also have different ascending projection patterns to the inferior colliculus (IC). Glycinergic LSO PNs project ipsilaterally while glutamatergic one's projections vary in laterality by species. In animals with good low‐frequency hearing (<3 kHz) such as cats and gerbils, glutamatergic LSO PNs have both ipsilateral and contralateral projections; however, rats that lack this ability only have the contralateral pathway. Additionally, in gerbils, the glutamatergic ipsilateral projecting LSO PNs are biased to the low‐frequency limb of the LSO suggesting this pathway may be an adaptation for low‐frequency hearing. To further test this premise, we examined the distribution and IC projection pattern of LSO PNs in another high‐frequency specialized species using mice by combining in situ hybridization and retrograde tracer injections. We observed no overlap between glycinergic and glutamatergic LSO PNs confirming they are distinct cell populations in mice as well. We found that mice also lack the ipsilateral glutamatergic projection from LSO to IC and that their LSO PN types do not exhibit pronounced tonotopic biases. These data provide insights into the cellular organization of the superior olivary complex and its output to higher processing centers that may underlie functional segregation of information.