Neuronal Mechanism for Critical Period Unit, Okinawa Institute of Science and Technology (OIST) Graduate University, Okinawa, Japan.
WPI-IRCN, The University of Tokyo, Tokyo, Japan.
Nat Commun. 2022 Aug 16;13(1):4442. doi: 10.1038/s41467-022-32207-1.
Social interactions are essential when learning to communicate. In human speech and bird song, infants must acquire accurate vocalization patterns and learn to associate them with live tutors and not mimetic sources. However, the neural mechanism of social reality during vocal learning remains unknown. Here, we characterize a neural circuit for social authentication in support of accurate song learning in the zebra finch. We recorded neural activity in the attention/arousal state control center, the locus coeruleus (LC), of juvenile birds during song learning from a live adult tutor. LC activity increased with real, not artificial, social information during learning that enhanced the precision and robustness of the learned song. During live social song learning, LC activity regulated long-term song-selective neural responsiveness in an auditory memory region, the caudomedial nidopallium (NCM). In accord, optogenetic inhibition of LC presynaptic signaling in the NCM reduced NCM neuronal responsiveness to live tutor singing and impaired song learning. These results demonstrate that the LC-NCM neural circuit integrates sensory evidence of real social interactions, distinct from song acoustic features, to authenticate song learning. The findings suggest a general mechanism for validating social information in brain development.
社会互动在学习交流中至关重要。在人类言语和鸟类鸣唱中，婴儿必须习得准确的发声模式，并学会将其与真实的导师而非模仿源联系起来。然而，在发声学习过程中，社会现实的神经机制尚不清楚。本研究在支持斑马雀准确鸣唱学习的过程中，鉴定了一个支持社会认证的神经回路。在从活体成年导师处学习鸣唱的过程中，我们记录了幼鸟注意力/唤醒状态控制中心蓝斑核（LC）的神经活动。LC 活动在学习过程中随真实而非人工的社会信息而增加，从而提高了学习歌曲的精度和稳健性。在活体社交鸣唱学习过程中，LC 活动调节了听觉记忆区尾侧中脑隔核（NCM）中对鸣唱具有长期选择性的神经元反应性。相应地，NCM 中 LC 突触前信号的光遗传学抑制降低了 NCM 神经元对活体导师鸣唱的反应性，并损害了鸣唱学习。这些结果表明，LC-NCM 神经回路整合了真实社会互动的感官证据，与鸣唱声学特征不同，以验证鸣唱学习。该发现表明了大脑发育中验证社会信息的一般机制。
