Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan.
Advanced Comprehensive Research Organization, Teikyo University, 2-21-1 Kaga, Itabashi-ku, Tokyo 173-0003, Japan.
Neurosci Res. 2022 Aug;181:66-73. doi: 10.1016/j.neures.2022.03.008. Epub 2022 Mar 24.
Male songbirds are highly motivated to sing undirected song (US) as juveniles during song learning, and as adults. Given that singing US is a self-driven, elaborated behavior, we would expect to see preparatory activity in the striatal area prior to vocalization, and this preparatory activity could have different characteristics compared to activity driven by calls. In general, songs are longer, complex and influenced by learning while calls are shorter, simpler, and less influenced by experience. The present study recorded neural activity in Area X, a nucleus of the basal ganglia, in male Java sparrows (Lonchura oryzivora) in a sound-proof box and analyzed differences in activity change before US and trill-calls. Trill-calls were often emitted in social arousal, but occasionally emitted when alone. We saw a gradual increase in firing rate for about 2.3 s prior to the onset of US, and a shorter increase of about 1.3 s in firing rate prior to the onset of trill-calls. The results reveal that initiating US may be influenced by a prolonged and specific activity increase in the extent that is not seen with trill-calls. Results suggest that direct or indirect projections to Area X, which may reflect motivational state, could be the cause of this activity change.
雄性鸣禽在幼年学习期间和成年后都非常热衷于自发地唱未经指导的歌曲（US）。鉴于唱 US 是一种自我驱动的、精心制作的行为，我们预计在发声前纹状体区域会有预备活动，而这种预备活动与由叫声驱动的活动可能具有不同的特征。一般来说，歌曲比叫声更长、更复杂，受学习的影响更大，而叫声则更短、更简单，受经验的影响更小。本研究在隔音箱中记录了雄性 Java 麻雀（Lonchura oryzivora）的基底神经节核团 X 区的神经活动，并分析了 US 和颤音呼叫前的活动变化差异。颤音呼叫通常在社交唤醒时发出，但偶尔也会在独处时发出。我们发现，在 US 开始前，大约有 2.3 秒的时间，放电率逐渐增加，在颤音呼叫开始前，放电率的增加时间约为 1.3 秒。结果表明，发起 US 可能受到延长和特定活动增加的影响，而这种影响在颤音呼叫中并不明显。结果表明，可能反映动机状态的直接或间接投射到 X 区，可能是这种活动变化的原因。
