Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
Departments of Physiology and Psychiatry, University of California-San Francisco, San Francisco, CA 94158, USA.
Science. 2021 Feb 12;371(6530). doi: 10.1126/science.abd9704.
Birds display advanced behaviors, including vocal learning and problem-solving, yet lack a layered neocortex, a structure associated with complex behavior in mammals. To determine whether these behavioral similarities result from shared or distinct neural circuits, we used single-cell RNA sequencing to characterize the neuronal repertoire of the songbird song motor pathway. Glutamatergic vocal neurons had considerable transcriptional similarity to neocortical projection neurons; however, they displayed regulatory gene expression patterns more closely related to neurons in the ventral pallium. Moreover, while γ-aminobutyric acid-releasing neurons in this pathway appeared homologous to those in mammals and other amniotes, the most abundant avian class is largely absent in the neocortex. These data suggest that songbird vocal circuits and the mammalian neocortex have distinct developmental origins yet contain transcriptionally similar neurons.
鸟类表现出高级行为，包括声乐学习和解决问题，但缺乏与哺乳动物复杂行为相关的分层新皮质。为了确定这些行为相似性是源于共同的还是不同的神经回路，我们使用单细胞 RNA 测序来描述鸣禽歌曲运动通路的神经元图谱。谷氨酸能发声神经元与新皮质投射神经元具有相当大的转录相似性；然而，它们表现出的调节基因表达模式与腹侧苍白球中的神经元更为密切相关。此外，尽管该通路中的γ-氨基丁酸释放神经元与哺乳动物和其他羊膜动物中的神经元同源，但在新皮质中，最丰富的鸟类类群却大量缺失。这些数据表明，鸣禽发声回路和哺乳动物新皮质具有不同的发育起源，但包含转录相似的神经元。
