Alhelo Hasan, Dogiparthi Jaswanthi, Baizer Joan S, Hof Patrick R, Sherwood Chet C, Kulesza Randy
Department of Anatomy, Lake Erie College of Osteopathic Medicine, 1858 West Grandview Blvd, Erie, PA 16509, USA.
Department of Physiology and Biophysics, University of Buffalo, Buffalo, NY, USA.
Hear Res. 2023 Mar 15;430:108698. doi: 10.1016/j.heares.2023.108698. Epub 2023 Jan 23.
The superior olivary complex (SOC) is a collection of nuclei in the hindbrain of mammals with numerous roles in hearing, including localization of sound sources in the environment, encoding temporal and spectral elements of sound, and descending modulation of the cochlea. While there have been several investigations of the SOC in primates, there are discrepancies in the descriptions of nuclear borders and even the presence of certain cell groups among studies and species. Herein, we aimed to clarify some of these issues by characterizing the SOC from chimpanzees using Nissl staining, quantitative morphometry and immunohistochemistry. We found the medial superior olive (MSO) to be the largest of the SOC nuclei and the arrangement of its neurons and peri-MSO to be very similar to humans. Additionally, we found neurons in the medial nucleus of the trapezoid body (MNTB) to be immunopositive for the calcium binding protein calbindin. Further, most neurons in the MNTB, and some neurons in the lateral nucleus of the trapezoid body were associated with large, calretinin-immunoreactive calyx terminals. Together, these findings indicate the organization of the SOC of chimpanzees is organized very similar to the SOC in humans and suggests modifications to this region among species consistent with differences in head/body size, restricted hearing range and sensitivity to low frequency sounds.
上橄榄复合体（SOC）是哺乳动物后脑的一组核团，在听觉中具有多种作用，包括在环境中定位声源、编码声音的时间和频谱成分以及对耳蜗的下行调制。虽然对灵长类动物的上橄榄复合体已经有多项研究，但在核边界的描述甚至不同研究和物种中某些细胞群的存在方面存在差异。在此，我们旨在通过使用尼氏染色、定量形态测量和免疫组织化学对黑猩猩的上橄榄复合体进行特征描述来澄清其中一些问题。我们发现内侧上橄榄核（MSO）是上橄榄复合体中最大的核，其神经元和内侧上橄榄核周围的排列与人类非常相似。此外，我们发现梯形体内侧核（MNTB）中的神经元对钙结合蛋白钙结合蛋白呈免疫阳性。此外，MNTB中的大多数神经元以及梯形体外侧核中的一些神经元与大型、钙视网膜蛋白免疫反应性花萼终末相关。总之，这些发现表明黑猩猩的上橄榄复合体的组织结构与人类的上橄榄复合体非常相似，并表明该区域在不同物种之间的变化与头/身体大小、有限的听力范围和对低频声音的敏感性差异一致。
