Temperate zone songbird species, such as the canary (Serinus canaria), can serve as model systems to investigate adult seasonal plasticity in brain and behavior. An increase in day length, experienced by canaries in the early spring stimulates gonadal recrudescence and an associated increase in circulating testosterone concentrations. This increase in plasma testosterone results in marked morphological changes in well-defined neural circuitry regulating reproductive behaviors including birdsong as well as behavioral changes such as increases in song length and complexity. An obvious measure of plasticity in neural morphology can be assessed via changes in brain nuclei volume and testosterone actions on a number of cellular features including the integration and incorporation of new neurons in the adult canary brain. Previous work in our lab suggests that there may be systematic intraspecific variability within canaries in testosterone-induced adult neuroplasticity. For example, the song nucleus HVC increases in size in response to testosterone in male canaries but we found that males of the American Singer strain exhibited minimal and variable responses as compared to other canary strains such as the Border canary strain, which is thought to be closer to wild type canaries. In this study, we systematically compared the effects of testosterone on the volume of song nuclei and the number of new neurons as assessed with the neurogenesis marker doublecortin in American Singer and Border canaries. We found more pronounced testosterone-induced neuroplasticity in the Border strain than the American Singer. These data suggest that the process of selection for certain strain phenotypes is also associated with significant changes in hormone-regulated brain plasticity.

中文翻译：

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两个金丝雀菌株中睾丸激素诱导的神经可塑性的种内变异。

温带区的鸣鸟物种，例如金丝雀（Serinus canaria），可以作为模型系统来研究成年人大脑和行为的季节性可塑性。金丝雀在早春经历的日长的增加会刺激性腺的复发，并随之增加循环睾丸激素的浓度。血浆睾丸激素的这种增加导致明确定义的神经回路的形态发生显着变化，该神经回路调节包括鸟鸣声在内的生殖行为，以及诸如歌曲长度和复杂性增加之类的行为变化。可以通过改变大脑核体积和睾丸激素对许多细胞功能的作用来评估神经形态学可塑性的一种明显方法，这些功能包括在成年金丝雀脑中新神经元的整合和整合。我们实验室以前的工作表明，在睾丸激素诱导的成人神经可塑性中，金丝雀内可能存在系统内种内变异性。例如，在男性金丝雀中，响应于睾丸激素，歌核HVC的大小会增加，但我们发现，与其他金丝雀菌株（例如Border金丝雀菌株）相比，美国歌手歌手的男性表现出最小且可变的响应。更接近野生型金丝雀。在这项研究中，我们系统地比较了睾丸激素对歌曲核的体积和新神经元数量的影响，并用神经发生标记doublecortin在美国歌手和边境金丝雀中进行了评估。我们发现Border菌株中的睾丸激素诱导的神经可塑性比American Singer更明显。