Meitzen John, Thompson Christopher K, Choi Heejung, Perkel David J, Brenowitz Eliot A
Graduate Program in Neurobiology and Behavior, University of Washington, Seattle, WA 98195, USA.
Horm Behav. 2009 Jan;55(1):217-27. doi: 10.1016/j.yhbeh.2008.10.006. Epub 2008 Nov 1.
Seasonal changes in behavior and in its underlying neural substrate are common across animal taxa. These changes are often triggered by steroid sex hormones. Song in seasonally breeding songbirds provides an excellent example of this phenomenon. In these species, dramatic seasonal changes mediated by testosterone and its metabolites occur in adult song behavior and in the neural circuitry controlling song. While song rate can quickly change in response to seasonal breeding cues, it is unknown how quickly other aspects of song change, particularly the stereotypy of song phonology and syntax. In this study we determined whether and how quickly song rate, phonology, and syntax change in response to breeding and non-breeding physiological cues. We asked these questions using Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii), a closed-ended learner with well-characterized changes in the neural circuitry controlling song behavior. We exposed ten photosensitive sparrows to long-day photoperiod and implanted them with subcutaneous testosterone pellets (day 0) to simulate breeding conditions. We continuously recorded song and found that song rate increased quickly, reaching maximum around day 6. The stereotypy of song phonology changed more slowly, reaching maximum by day 10 or later. Song syntax changed minimally after day 6, the earliest time point examined. After 21 days, we transitioned five birds from breeding to non-breeding condition. Song rate declined precipitously. These results suggest that while song rate changes quickly, song phonology changes more slowly, generally following or in parallel with previously investigated changes in the neural substrate.
行为及其潜在神经基质的季节性变化在动物类群中很常见。这些变化通常由类固醇性激素触发。季节性繁殖鸣禽的鸣叫就是这一现象的一个很好的例子。在这些物种中，由睾酮及其代谢物介导的显著季节性变化发生在成年鸣叫行为以及控制鸣叫的神经回路中。虽然鸣叫速率可以根据季节性繁殖线索迅速变化，但鸣叫的其他方面变化有多快尚不清楚，特别是鸣叫音系和句法的刻板性。在这项研究中，我们确定了鸣叫速率、音系和句法是否以及多快会因繁殖和非繁殖生理线索而变化。我们用甘贝尔氏白冠雀（Zonotrichia leucophrys gambelii）来研究这些问题，这是一种封闭式学习者，其控制鸣叫行为的神经回路变化特征明确。我们让十只对光敏感的麻雀暴露在长日照光周期下，并给它们皮下植入睾酮丸剂（第0天）以模拟繁殖条件。我们持续记录鸣叫，发现鸣叫速率迅速增加，在第6天左右达到最大值。鸣叫音系的刻板性变化较慢，在第10天或更晚达到最大值。鸣叫句法在第6天（最早检查的时间点）之后变化最小。21天后，我们将五只鸟从繁殖状态转变为非繁殖状态。鸣叫速率急剧下降。这些结果表明，虽然鸣叫速率变化迅速，但鸣叫音系变化较慢，通常跟随或与先前研究的神经基质变化并行。
