López-Murillo Carolina, Hinestroza-Morales Santiago, Henny Pablo, Toledo Jorge, Cardona-Gómez Gloria Patricia, Rivera-Gutiérrez Héctor, Posada-Duque Rafael
Área de Neurofisiología Celular, Grupo de Neurociencias de Antioquia, Instituto de Biología, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Medellin, Colombia.
Laboratorio de Neuroanatomía, Departamento de Anatomía, and Centro Interdisciplinario de Neurociencia, NeuroUC, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
Front Neuroanat. 2024 Mar 27;18:1339308. doi: 10.3389/fnana.2024.1339308. eCollection 2024.
The house wren shows complex song, and the rufous-tailed hummingbird has a simple song. The location of vocal brain areas supports the song's complexity; however, these still need to be studied. The astrocytic population in songbirds appears to be associated with change in vocal control nuclei; however, astrocytic distribution and morphology have not been described in these species. Consequently, we compared the distribution and volume of the vocal brain areas: HVC, RA, Area X, and LMAN, cell density, and the morphology of astrocytes in the house wren and the rufous-tailed hummingbird. Individuals of the two species were collected, and their brains were analyzed using serial Nissl- NeuN- and MAP2-stained tissue scanner imaging, followed by 3D reconstructions of the vocal areas; and GFAP and S100β astrocytes were analyzed in both species. We found that vocal areas were located close to the cerebral midline in the house wren and a more lateralized position in the rufous-tailed hummingbird. The LMAN occupied a larger volume in the rufous-tailed hummingbird, while the RA and HVC were larger in the house wren. While Area X showed higher cell density in the house wren than the rufous-tailed hummingbird, the LMAN showed a higher density in the rufous-tailed hummingbird. In the house wren, GFAP astrocytes in the same bregma where the vocal areas were located were observed at the laminar edge of the pallium (LEP) and in the vascular region, as well as in vocal motor relay regions in the pallidum and mesencephalon. In contrast, GFAP astrocytes were found in LEP, but not in the pallidum and mesencephalon in hummingbirds. Finally, when comparing GFAP astrocytes in the LEP region of both species, house wren astrocytes exhibited significantly more complex morphology than those of the rufous-tailed hummingbird. These findings suggest a difference in the location and cellular density of vocal circuits, as well as morphology of GFAP astrocytes between the house wren and the rufous-tailed hummingbird.
家鹪鹩表现出复杂的歌声，而棕尾蜂鸟的歌声则较为简单。发声脑区的位置支持了歌声的复杂性；然而，这些仍有待研究。鸣禽中的星形胶质细胞群体似乎与发声控制核的变化有关；然而，这些物种中星形胶质细胞的分布和形态尚未得到描述。因此，我们比较了家鹪鹩和棕尾蜂鸟发声脑区（HVC、RA、X区和LMAN）的分布和体积、细胞密度以及星形胶质细胞的形态。收集了这两个物种的个体，并使用连续尼氏染色、NeuN染色和MAP2染色的组织扫描仪成像对它们的大脑进行分析，随后对发声区域进行三维重建；并对两个物种中的GFAP和S100β星形胶质细胞进行了分析。我们发现，家鹪鹩的发声区域位于大脑中线附近，而棕尾蜂鸟的发声区域位置更偏向外侧。LMAN在棕尾蜂鸟中占据更大的体积，而RA和HVC在家鹪鹩中更大。虽然X区在家鹪鹩中的细胞密度高于棕尾蜂鸟，但LMAN在棕尾蜂鸟中的密度更高。在家鹪鹩中，在发声区域所在的相同脑区水平，在大脑皮层的层状边缘（LEP）、血管区域以及苍白球和中脑的发声运动中继区域观察到了GFAP星形胶质细胞。相比之下，在棕尾蜂鸟的LEP中发现了GFAP星形胶质细胞，但在苍白球和中脑中未发现。最后，当比较两个物种LEP区域中的GFAP星形胶质细胞时，家鹪鹩的星形胶质细胞形态比棕尾蜂鸟的明显更复杂。这些发现表明，家鹪鹩和棕尾蜂鸟在发声回路的位置和细胞密度以及GFAP星形胶质细胞的形态方面存在差异。
