Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley California 94720.
Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, Berkeley California 94720.
J Neurosci. 2023 Apr 5;43(14):2579-2596. doi: 10.1523/JNEUROSCI.0643-22.2023. Epub 2023 Mar 1.
Many social animals can recognize other individuals by their vocalizations. This requires a memory system capable of mapping incoming acoustic signals to one of many known individuals. Using the zebra finch, a social songbird that uses songs and distance calls to communicate individual identity (Elie and Theunissen, 2018), we tested the role of two cortical-like brain regions in a vocal recognition task. We found that the rostral region of the Cadomedial Nidopallium (NCM), a secondary auditory region of the avian pallium, was necessary for maintaining auditory memories for conspecific vocalizations in both male and female birds, whereas HVC (used as a proper name), a premotor areas that gates auditory input into the vocal motor and song learning pathways in male birds (Roberts and Mooney, 2013), was not. Both NCM and HVC have previously been implicated for processing the tutor song in the context of song learning (Sakata and Yazaki-Sugiyama, 2020). Our results suggest that NCM might not only store songs as templates for future vocal imitation but also songs and calls for perceptual discrimination of vocalizers in both male and female birds. NCM could therefore operate as a site for auditory memories for vocalizations used in various facets of communication. We also observed that new auditory memories could be acquired without intact HVC or NCM but that for these new memories NCM lesions caused deficits in either memory capacity or auditory discrimination. These results suggest that the high-capacity memory functions of the avian pallial auditory system depend on NCM. Many aspects of vocal communication require the formation of auditory memories. Voice recognition, for example, requires a memory for vocalizers to identify acoustical features. In both birds and primates, the locus and neural correlates of these high-level memories remain poorly described. Previous work suggests that this memory formation is mediated by high-level sensory areas, not traditional memory areas such as the hippocampus. Using lesion experiments, we show that one secondary auditory brain region in songbirds that had previously been implicated in storing song memories for vocal imitation is also implicated in storing vocal memories for individual recognition. The role of the neural circuits in this region in interpreting the meaning of communication calls should be investigated in the future.
许多社交动物可以通过声音来识别其他个体。这需要一个记忆系统，能够将传入的声信号映射到许多已知个体之一。我们使用斑胸草雀，一种使用歌曲和距离叫声来传达个体身份的社交鸣禽（Elie 和 Theunissen，2018），在一个声音识别任务中测试了两个皮质样脑区的作用。我们发现，中脑背侧冠部（NCM）的喙部，一个禽类大脑皮层的次级听觉区，对于维持雄性和雌性鸟类对同种声音的听觉记忆是必要的，而 HVC（用作专有名词），一个门控听觉输入到雄性鸟类的发声运动和歌曲学习途径的前运动区（Roberts 和 Mooney，2013），则不是。NCM 和 HVC 以前都被认为是在歌曲学习的背景下处理导师歌曲的（Sakata 和 Yazaki-Sugiyama，2020）。我们的结果表明，NCM 不仅可能存储歌曲作为未来声音模仿的模板，而且还可能存储歌曲和叫声，用于雄性和雌性鸟类中声音发声者的感知辨别。因此，NCM 可能作为一个用于各种交流方面声音的听觉记忆的站点。我们还观察到，即使没有完整的 HVC 或 NCM，也可以获得新的听觉记忆，但对于这些新的记忆，NCM 损伤会导致记忆容量或听觉辨别能力的缺陷。这些结果表明，禽类大脑皮层听觉系统的高容量记忆功能依赖于 NCM。许多声音交流方面都需要形成听觉记忆。例如，声音识别需要对声音发声者的记忆来识别声音特征。在鸟类和灵长类动物中，这些高级记忆的位置和神经相关物仍然描述得很差。以前的工作表明，这种记忆形成是由高级感觉区域介导的，而不是传统的记忆区域，如海马体。通过损伤实验，我们表明，在以前被认为参与存储用于声音模仿的歌曲记忆的鸣禽的一个次级听觉脑区，也参与存储用于个体识别的声音记忆。未来应该研究该区域中的神经回路在解释交流叫声的意义方面的作用。
