Department of Biology, Wesleyan University, Middletown, Connecticut, USA.
Program in Neuroscience and Behavior, Wesleyan University, Middletown, Connecticut, USA.
J Comp Neurol. 2022 Apr;530(5):792-803. doi: 10.1002/cne.25245. Epub 2021 Nov 15.
Adult male zebra finches (Taeniopygia guttata) continually incorporate adult-born neurons into HVC, a telencephalic brain region necessary for the production of learned song. These neurons express activity-dependent immediate early genes (e.g., zenk and c-fos) following song production, suggesting that these neurons are active during song production. Half of these adult-born HVC neurons (HVC NNs) can be backfilled from the robust nucleus of the arcopallium (RA) and are a part of the vocal motor pathway underlying learned song production, but the other half do not backfill from RA, and they remain to be characterized. Here, we used cell birth-dating, retrograde tract tracing, and immunofluorescence to demonstrate that half of all HVC NNs express the phosphoprotein DARPP-32, a protein associated with dopamine receptor expression. We also demonstrate that DARPP-32+ HVC NNs are contacted by tyrosine hydroxylase immunoreactive fibers, suggesting that they receive catecholaminergic input, have transiently larger nuclei than DARPP-32-neg HVC NNs, and do not backfill from RA. Taken together, these findings help characterize a group of HVC NNs that have no apparent projections to RA and so far have eluded positive identification other than HVC NN status.
成年雄性斑马雀（Taeniopygia guttata）不断将成年新生神经元整合到 HVC 中，HVC 是大脑前额叶区域，是产生习得性歌曲所必需的。这些神经元在产生歌曲后表达活性依赖性即时早期基因（如 zenk 和 c-fos），表明这些神经元在产生歌曲时是活跃的。这些成年新生 HVC 神经元（HVC NNs）的一半可以从弓状核的粗壮核（RA）回溯填充，并且是习得性歌曲产生的发声运动途径的一部分，但另一半不能从 RA 回溯填充，它们仍有待表征。在这里，我们使用细胞出生标记、逆行轨迹追踪和免疫荧光技术证明，所有 HVC NNs 的一半表达磷酸化蛋白 DARPP-32，这是一种与多巴胺受体表达相关的蛋白。我们还证明 DARPP-32+HVC NNs 被酪氨酸羟化酶免疫反应性纤维接触，这表明它们接收儿茶酚胺能输入，细胞核比 DARPP-32-HVC NNs 暂时更大，并且不能从 RA 回溯填充。总之，这些发现有助于表征一组 HVC NNs，它们没有明显的投射到 RA，并且除了 HVC NN 状态外，迄今尚未得到明确识别。
