在所有哺乳动物中,上橄榄复合体(SOC)包括一组对声音定位很重要的听觉脑干核。它的主要原子核,外侧上橄榄(LSO)和内侧上橄榄(MSO)过程的耳间时间和强度差异,这是声音在水平面定位的主要线索。齿鲸(齿形鲸)严重依赖听觉和回声定位来觅食,定位,以及通信和定位声音的敏锐度。对齿骨中SOC的研究提供了对水下听力和回声定位的适应的见解。然而,目前缺乏牙切齿的定量解剖学数据。我们量化了体积,神经元总数,使用卡瓦列里原理和无偏立体光学分馏器,六只普通海豚(Delphinusdelphis)的LSO的神经元密度。我们的结果表明,德尔菲斯的LSO体积为150+(SD=27)mm3,平均比人类的LSO大69(SEM=19)倍,或比人类LSO和MSO总和大37倍(SEM=11)。delphis的LSO包含20,876±(SD=3300)个神经元。相比之下,人类脑干报告的数据表明,LSO只有大约1/4这个数字,但LSO和MSO的总和大约是相同的数字(21,100)。LSO神经元的横截面范围为21至25μm(短轴)和44至61μm(长轴)。LSO神经元堆积密度为1080±(SD=204)个神经元/mm3,大约是人类LSO神经元密度的一半。SMI-32免疫组织化学用于可视化LSO中的投影神经元,并揭示了主要的存在,边缘,和横切面上的多极神经元。LSO的独特形态可能反映了普通海豚对超高频的出色敏感性,以及检测和分析声音及其位置的能力,这是其水下空间定位和回声定位任务的一部分。
In all mammals, the superior olivary complex (SOC) comprises a group of auditory brainstem nuclei that are important for sound localization. Its principal nuclei, the lateral superior olive (LSO) and the medial superior olive (MSO) process interaural time and intensity differences, which are the main cues for sound localization in the horizontal plane. Toothed whales (odontocetes) rely heavily on hearing and echolocation for foraging, orientation, and communication and localize sound with great acuity. The investigation of the SOC in odontocetes provides insight into adaptations to underwater hearing and echolocation. However, quantitative anatomical data for odontocetes are currently lacking. We quantified the volume, total neuron number, and neuron density of the
LSO of six common dolphins (Delphinus delphis) using the Cavalieri principle and the unbiased stereology optical fractionator. Our results show that the LSO in D. delphis has a volume of 150 + (SD = 27) mm3 , which is on average 69 (SEM = 19) times larger than the
LSO in human, or 37 (SEM = 11) times larger than the human
LSO and MSO combined. The
LSO of D. delphis contains 20,876 ± (SD = 3300) neurons. In comparison, data reported for the human brainstem indicate the LSO has only about ¼ that number but about the same number for the
LSO and MSO combined (21,100). LSO neurons range from 21 to 25 μm (minor axis) and from 44 to 61 μm (major axis) in transverse sections. The
LSO neuron packing density is 1080 ± (SD = 204) neurons/mm3 , roughly half of the
LSO neuron density in human. SMI-32-immunohistochemistry was used to visualize projection neurons in the LSO and revealed the presence of principal, marginal, and multipolar neurons in transverse sections. The distinct morphology of the LSO likely reflects the common dolphin\'s superb sensitivity to ultra-high frequencies and ability to detect and analyze sounds and their location as part of its underwater spatial localization and echolocation tasks.